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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 static call update from Thomas Gleixner:
"A single fix for static calls to make the trampoline patching more
robust by placing explicit signature bytes after the call trampoline
to prevent patching random other jumps like the CFI jump table
entries"
* tag 'locking-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
static_call,x86: Robustify trampoline patching
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Borislav Petkov:
- Avoid touching ~100 config files in order to be able to select the
preemption model
- clear cluster CPU masks too, on the CPU unplug path
- prevent use-after-free in cfs
- Prevent a race condition when updating CPU cache domains
- Factor out common shared part of smp_prepare_cpus() into a common
helper which can be called by both baremetal and Xen, in order to fix
a booting of Xen PV guests
* tag 'sched_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
preempt: Restore preemption model selection configs
arch_topology: Fix missing clear cluster_cpumask in remove_cpu_topology()
sched/fair: Prevent dead task groups from regaining cfs_rq's
sched/core: Mitigate race cpus_share_cache()/update_top_cache_domain()
x86/smp: Factor out parts of native_smp_prepare_cpus()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Add the model number of a new, Raptor Lake CPU, to intel-family.h
- Do not log spurious corrected MCEs on SKL too, due to an erratum
- Clarify the path of paravirt ops patches upstream
- Add an optimization to avoid writing out AMX components to sigframes
when former are in init state
* tag 'x86_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Add Raptor Lake to Intel family
x86/mce: Add errata workaround for Skylake SKX37
MAINTAINERS: Add some information to PARAVIRT_OPS entry
x86/fpu: Optimize out sigframe xfeatures when in init state
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Add model ID for Raptor Lake.
[ dhansen: These get added as soon as possible so that folks doing
development can leverage them. ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20211112182835.924977-1-tony.luck@intel.com
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* Fix misuse of gfn-to-pfn cache when recording guest steal time / preempted status
* Fix selftests on APICv machines
* Fix sparse warnings
* Fix detection of KVM features in CPUID
* Cleanups for bogus writes to MSR_KVM_PV_EOI_EN
* Fixes and cleanups for MSR bitmap handling
* Cleanups for INVPCID
* Make x86 KVM_SOFT_MAX_VCPUS consistent with other architectures
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Add support for AMD SEV and SEV-ES intra-host migration support. Intra
host migration provides a low-cost mechanism for userspace VMM upgrades.
In the common case for intra host migration, we can rely on the normal
ioctls for passing data from one VMM to the next. SEV, SEV-ES, and other
confidential compute environments make most of this information opaque, and
render KVM ioctls such as "KVM_GET_REGS" irrelevant. As a result, we need
the ability to pass this opaque metadata from one VMM to the next. The
easiest way to do this is to leave this data in the kernel, and transfer
ownership of the metadata from one KVM VM (or vCPU) to the next. In-kernel
hand off makes it possible to move any data that would be
unsafe/impossible for the kernel to hand directly to userspace, and
cannot be reproduced using data that can be handed to userspace.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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KVM_CAP_NR_VCPUS is used to get the "recommended" maximum number of
VCPUs and arm64/mips/riscv report num_online_cpus(). Powerpc reports
either num_online_cpus() or num_present_cpus(), s390 has multiple
constants depending on hardware features. On x86, KVM reports an
arbitrary value of '710' which is supposed to be the maximum tested
value but it's possible to test all KVM_MAX_VCPUS even when there are
less physical CPUs available.
Drop the arbitrary '710' value and return num_online_cpus() on x86 as
well. The recommendation will match other architectures and will mean
'no CPU overcommit'.
For reference, QEMU only queries KVM_CAP_NR_VCPUS to print a warning
when the requested vCPU number exceeds it. The static limit of '710'
is quite weird as smaller systems with just a few physical CPUs should
certainly "recommend" less.
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211111134733.86601-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Currently when kvm_update_cpuid_runtime() runs, it assumes that the
KVM_CPUID_FEATURES leaf is located at 0x40000001. This is not true,
however, if Hyper-V support is enabled. In this case the KVM leaves will
be offset.
This patch introdues as new 'kvm_cpuid_base' field into struct
kvm_vcpu_arch to track the location of the KVM leaves and function
kvm_update_kvm_cpuid_base() (called from kvm_set_cpuid()) to locate the
leaves using the 'KVMKVMKVM\0\0\0' signature (which is now given a
definition in kvm_para.h). Adjustment of KVM_CPUID_FEATURES will hence now
target the correct leaf.
NOTE: A new for_each_possible_hypervisor_cpuid_base() macro is intoduced
into processor.h to avoid having duplicate code for the iteration
over possible hypervisor base leaves.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Message-Id: <20211105095101.5384-3-pdurrant@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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KVM_GUESTDBG_BLOCKIRQ relies on interrupts being injected using
standard kvm's inject_pending_event, and not via APICv/AVIC.
Since this is a debug feature, just inhibit APICv/AVIC while
KVM_GUESTDBG_BLOCKIRQ is in use on at least one vCPU.
Fixes: 61e5f69ef0837 ("KVM: x86: implement KVM_GUESTDBG_BLOCKIRQ")
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211108090245.166408-1-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In commit b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is
not missed") we switched to using a gfn_to_pfn_cache for accessing the
guest steal time structure in order to allow for an atomic xchg of the
preempted field. This has a couple of problems.
Firstly, kvm_map_gfn() doesn't work at all for IOMEM pages when the
atomic flag is set, which it is in kvm_steal_time_set_preempted(). So a
guest vCPU using an IOMEM page for its steal time would never have its
preempted field set.
Secondly, the gfn_to_pfn_cache is not invalidated in all cases where it
should have been. There are two stages to the GFN->PFN conversion;
first the GFN is converted to a userspace HVA, and then that HVA is
looked up in the process page tables to find the underlying host PFN.
Correct invalidation of the latter would require being hooked up to the
MMU notifiers, but that doesn't happen---so it just keeps mapping and
unmapping the *wrong* PFN after the userspace page tables change.
In the !IOMEM case at least the stale page *is* pinned all the time it's
cached, so it won't be freed and reused by anyone else while still
receiving the steal time updates. The map/unmap dance only takes care
of the KVM administrivia such as marking the page dirty.
Until the gfn_to_pfn cache handles the remapping automatically by
integrating with the MMU notifiers, we might as well not get a
kernel mapping of it, and use the perfectly serviceable userspace HVA
that we already have. We just need to implement the atomic xchg on
the userspace address with appropriate exception handling, which is
fairly trivial.
Cc: stable@vger.kernel.org
Fixes: b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <3645b9b889dac6438394194bb5586a46b68d581f.camel@infradead.org>
[I didn't entirely agree with David's assessment of the
usefulness of the gfn_to_pfn cache, and integrated the outcome
of the discussion in the above commit message. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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For SEV to work with intra host migration, contents of the SEV info struct
such as the ASID (used to index the encryption key in the AMD SP) and
the list of memory regions need to be transferred to the target VM.
This change adds a commands for a target VMM to get a source SEV VM's sev
info.
Signed-off-by: Peter Gonda <pgonda@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Message-Id: <20211021174303.385706-3-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add guest api and guest kernel support for SEV live migration.
Introduces a new hypercall to notify the host of changes to the page
encryption status. If the page is encrypted then it must be migrated
through the SEV firmware or a helper VM sharing the key. If page is
not encrypted then it can be migrated normally by userspace. This new
hypercall is invoked using paravirt_ops.
Conflicts: sev_active() replaced by cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT).
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feature.
The guest support for detecting and enabling SEV Live migration
feature uses the following logic :
- kvm_init_plaform() checks if its booted under the EFI
- If not EFI,
i) if kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL), issue a wrmsrl()
to enable the SEV live migration support
- If EFI,
i) If kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL), read
the UEFI variable which indicates OVMF support for live migration
ii) the variable indicates live migration is supported, issue a wrmsrl() to
enable the SEV live migration support
The EFI live migration check is done using a late_initcall() callback.
Also, ensure that _bss_decrypted section is marked as decrypted in the
hypervisor's guest page encryption status tracking.
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Steve Rutherford <srutherford@google.com>
Message-Id: <b4453e4c87103ebef12217d2505ea99a1c3e0f0f.1629726117.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Invoke a hypercall when a memory region is changed from encrypted ->
decrypted and vice versa. Hypervisor needs to know the page encryption
status during the guest migration.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Message-Id: <0a237d5bb08793916c7790a3e653a2cbe7485761.1629726117.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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KVM hypercall framework relies on alternative framework to patch the
VMCALL -> VMMCALL on AMD platform. If a hypercall is made before
apply_alternative() is called then it defaults to VMCALL. The approach
works fine on non SEV guest. A VMCALL would causes #UD, and hypervisor
will be able to decode the instruction and do the right things. But
when SEV is active, guest memory is encrypted with guest key and
hypervisor will not be able to decode the instruction bytes.
To highlight the need to provide this interface, capturing the
flow of apply_alternatives() :
setup_arch() call init_hypervisor_platform() which detects
the hypervisor platform the kernel is running under and then the
hypervisor specific initialization code can make early hypercalls.
For example, KVM specific initialization in case of SEV will try
to mark the "__bss_decrypted" section's encryption state via early
page encryption status hypercalls.
Now, apply_alternatives() is called much later when setup_arch()
calls check_bugs(), so we do need some kind of an early,
pre-alternatives hypercall interface. Other cases of pre-alternatives
hypercalls include marking per-cpu GHCB pages as decrypted on SEV-ES
and per-cpu apf_reason, steal_time and kvm_apic_eoi as decrypted for
SEV generally.
Add SEV specific hypercall3, it unconditionally uses VMMCALL. The hypercall
will be used by the SEV guest to notify encrypted pages to the hypervisor.
This kvm_sev_hypercall3() function is abstracted and used as follows :
All these early hypercalls are made through early_set_memory_XX() interfaces,
which in turn invoke pv_ops (paravirt_ops).
This early_set_memory_XX() -> pv_ops.mmu.notify_page_enc_status_changed()
is a generic interface and can easily have SEV, TDX and any other
future platform specific abstractions added to it.
Currently, pv_ops.mmu.notify_page_enc_status_changed() callback is setup to
invoke kvm_sev_hypercall3() in case of SEV.
Similarly, in case of TDX, pv_ops.mmu.notify_page_enc_status_changed()
can be setup to a TDX specific callback.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steve Rutherford <srutherford@google.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-Id: <6fd25c749205dd0b1eb492c60d41b124760cc6ae.1629726117.git.ashish.kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Commit 66558b730f25 ("sched: Add cluster scheduler level for x86")
introduced cpu_l2c_shared_map mask which is expected to be initialized
by smp_op.smp_prepare_cpus(). That commit only updated
native_smp_prepare_cpus() version but not xen_pv_smp_prepare_cpus().
As result Xen PV guests crash in set_cpu_sibling_map().
While the new mask can be allocated in xen_pv_smp_prepare_cpus() one can
see that both versions of smp_prepare_cpus ops share a number of common
operations that can be factored out. So do that instead.
Fixes: 66558b730f25 ("sched: Add cluster scheduler level for x86")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/1635896196-18961-1-git-send-email-boris.ostrovsky@oracle.com
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Add a few signature bytes after the static call trampoline and verify
those bytes match before patching the trampoline. This avoids patching
random other JMPs (such as CFI jump-table entries) instead.
These bytes decode as:
d: 53 push %rbx
e: 43 54 rex.XB push %r12
And happen to spell "SCT".
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211030074758.GT174703@worktop.programming.kicks-ass.net
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git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic cleanup from Arnd Bergmann:
"This is a single cleanup from Peter Collingbourne, removing some dead
code"
* tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
arch: remove unused function syscall_set_arguments()
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- a series to speed up the boot of Xen PV guests
- some cleanups in Xen related code
- replacement of license texts with the appropriate SPDX headers and
fixing of wrong SPDX headers in Xen header files
- a small series making paravirtualized interrupt masking much simpler
and at the same time removing complaints of objtool
- a fix for Xen ballooning hogging workqueues for too long
- enablement of the Xen pciback driver for Arm
- some further small fixes/enhancements
* tag 'for-linus-5.16b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (22 commits)
xen/balloon: fix unused-variable warning
xen/balloon: rename alloc/free_xenballooned_pages
xen/balloon: add late_initcall_sync() for initial ballooning done
x86/xen: remove 32-bit awareness from startup_xen
xen: remove highmem remnants
xen: allow pv-only hypercalls only with CONFIG_XEN_PV
x86/xen: remove 32-bit pv leftovers
xen-pciback: allow compiling on other archs than x86
x86/xen: switch initial pvops IRQ functions to dummy ones
x86/xen: remove xen_have_vcpu_info_placement flag
x86/pvh: add prototype for xen_pvh_init()
xen: Fix implicit type conversion
xen: fix wrong SPDX headers of Xen related headers
xen/pvcalls-back: Remove redundant 'flush_workqueue()' calls
x86/xen: Remove redundant irq_enter/exit() invocations
xen-pciback: Fix return in pm_ctrl_init()
xen/x86: restrict PV Dom0 identity mapping
xen/x86: there's no highmem anymore in PV mode
xen/x86: adjust handling of the L3 user vsyscall special page table
xen/x86: adjust xen_set_fixmap()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu updates from Joerg Roedel:
- Intel IOMMU Updates fro Lu Baolu:
- Dump DMAR translation structure when DMA fault occurs
- An optimization in the page table manipulation code
- Use second level for GPA->HPA translation
- Various cleanups
- Arm SMMU Updates from Will
- Minor optimisations to SMMUv3 command creation and submission
- Numerous new compatible string for Qualcomm SMMUv2 implementations
- Fixes for the SWIOTLB based implemenation of dma-iommu code for
untrusted devices
- Add support for r8a779a0 to the Renesas IOMMU driver and DT matching
code for r8a77980
- A couple of cleanups and fixes for the Apple DART IOMMU driver
- Make use of generic report_iommu_fault() interface in the AMD IOMMU
driver
- Various smaller fixes and cleanups
* tag 'iommu-updates-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (35 commits)
iommu/dma: Fix incorrect error return on iommu deferred attach
iommu/dart: Initialize DART_STREAMS_ENABLE
iommu/dma: Use kvcalloc() instead of kvzalloc()
iommu/tegra-smmu: Use devm_bitmap_zalloc when applicable
iommu/dart: Use kmemdup instead of kzalloc and memcpy
iommu/vt-d: Avoid duplicate removing in __domain_mapping()
iommu/vt-d: Convert the return type of first_pte_in_page to bool
iommu/vt-d: Clean up unused PASID updating functions
iommu/vt-d: Delete dev_has_feat callback
iommu/vt-d: Use second level for GPA->HPA translation
iommu/vt-d: Check FL and SL capability sanity in scalable mode
iommu/vt-d: Remove duplicate identity domain flag
iommu/vt-d: Dump DMAR translation structure when DMA fault occurs
iommu/vt-d: Do not falsely log intel_iommu is unsupported kernel option
iommu/arm-smmu-qcom: Request direct mapping for modem device
iommu: arm-smmu-qcom: Add compatible for QCM2290
dt-bindings: arm-smmu: Add compatible for QCM2290 SoC
iommu/arm-smmu-qcom: Add SM6350 SMMU compatible
dt-bindings: arm-smmu: Add compatible for SM6350 SoC
iommu/arm-smmu-v3: Properly handle the return value of arm_smmu_cmdq_build_cmd()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the big set of driver core changes for 5.16-rc1.
All of these have been in linux-next for a while now with no reported
problems.
Included in here are:
- big update and cleanup of the sysfs abi documentation files and
scripts from Mauro. We are almost at the place where we can
properly check that the running kernel's sysfs abi is documented
fully.
- firmware loader updates
- dyndbg updates
- kernfs cleanups and fixes from Christoph
- device property updates
- component fix
- other minor driver core cleanups and fixes"
* tag 'driver-core-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (122 commits)
device property: Drop redundant NULL checks
x86/build: Tuck away built-in firmware under FW_LOADER
vmlinux.lds.h: wrap built-in firmware support under FW_LOADER
firmware_loader: move struct builtin_fw to the only place used
x86/microcode: Use the firmware_loader built-in API
firmware_loader: remove old DECLARE_BUILTIN_FIRMWARE()
firmware_loader: formalize built-in firmware API
component: do not leave master devres group open after bind
dyndbg: refine verbosity 1-4 summary-detail
gpiolib: acpi: Replace custom code with device_match_acpi_handle()
i2c: acpi: Replace custom function with device_match_acpi_handle()
driver core: Provide device_match_acpi_handle() helper
dyndbg: fix spurious vNpr_info change
dyndbg: no vpr-info on empty queries
dyndbg: vpr-info on remove-module complete, not starting
device property: Add missed header in fwnode.h
Documentation: dyndbg: Improve cli param examples
dyndbg: Remove support for ddebug_query param
dyndbg: make dyndbg a known cli param
dyndbg: show module in vpr-info in dd-exec-queries
...
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tl;dr: AMX state is ~8k. Signal frames can have space for this
~8k and each signal entry writes out all 8k even if it is zeros.
Skip writing zeros for AMX to speed up signal delivery by about
4% overall when AMX is in its init state.
This is a user-visible change to the sigframe ABI.
== Hardware XSAVE Background ==
XSAVE state components may be tracked by the processor as being
in their initial configuration. Software can detect which
features are in this configuration by looking at the XSTATE_BV
field in an XSAVE buffer or with the XGETBV(1) instruction.
Both the XSAVE and XSAVEOPT instructions enumerate features s
being in the initial configuration via the XSTATE_BV field in the
XSAVE header, However, XSAVEOPT declines to actually write
features in their initial configuration to the buffer. XSAVE
writes the feature unconditionally, regardless of whether it is
in the initial configuration or not.
Basically, XSAVE users never need to inspect XSTATE_BV to
determine if the feature has been written to the buffer.
XSAVEOPT users *do* need to inspect XSTATE_BV. They might also
need to clear out the buffer if they want to make an isolated
change to the state, like modifying one register.
== Software Signal / XSAVE Background ==
Signal frames have historically been written with XSAVE itself.
Each state is written in its entirety, regardless of being in its
initial configuration.
In other words, the signal frame ABI uses the XSAVE behavior, not
the XSAVEOPT behavior.
== Problem ==
This means that any application which has acquired permission to
use AMX via ARCH_REQ_XCOMP_PERM will write 8k of state to the
signal frame. This 8k write will occur even when AMX was in its
initial configuration and software *knows* this because of
XSTATE_BV.
This problem also exists to a lesser degree with AVX-512 and its
2k of state. However, AVX-512 use does not require
ARCH_REQ_XCOMP_PERM and is more likely to have existing users
which would be impacted by any change in behavior.
== Solution ==
Stop writing out AMX xfeatures which are in their initial state
to the signal frame. This effectively makes the signal frame
XSAVE buffer look as if it were written with a combination of
XSAVEOPT and XSAVE behavior. Userspace which handles XSAVEOPT-
style buffers should be able to handle this naturally.
For now, include only the AMX xfeatures: XTILE and XTILEDATA in
this new behavior. These require new ABI to use anyway, which
makes their users very unlikely to be broken. This XSAVEOPT-like
behavior should be expected for all future dynamic xfeatures. It
may also be extended to legacy features like AVX-512 in the
future.
Only attempt this optimization on systems with dynamic features.
Disable dynamic feature support (XFD) if XGETBV1 is unavailable
by adding a CPUID dependency.
This has been measured to reduce the *overall* cycle cost of
signal delivery by about 4%.
Fixes: 2308ee57d93d ("x86/fpu/amx: Enable the AMX feature in 64-bit mode")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "Chang S. Bae" <chang.seok.bae@intel.com>
Link: https://lore.kernel.org/r/20211102224750.FA412E26@davehans-spike.ostc.intel.com
|
|
Pull drm updates from Dave Airlie:
"Summary below. i915 starts to add support for DG2 GPUs, enables DG1
and ADL-S support by default, lots of work to enable DisplayPort 2.0
across drivers. Lots of documentation updates and fixes across the
board.
core:
- improve dma_fence, lease and resv documentation
- shmem-helpers: allocate WC pages on x86, use vmf_insert_pin
- sched fixes/improvements
- allow empty drm leases
- add dma resv iterator
- add more DP 2.0 headers
- DP MST helper improvements for DP2.0
dma-buf:
- avoid warnings, remove fence trace macros
bridge:
- new helper to get rid of panels
- probe improvements for it66121
- enable DSI EOTP for anx7625
fbdev:
- efifb: release runtime PM on destroy
ttm:
- kerneldoc switch
- helper to clear all DMA mappings
- pool shrinker optimizaton
- remove ttm_tt_destroy_common
- update ttm_move_memcpy for async use
panel:
- add new panel-edp driver
amdgpu:
- Initial DP 2.0 support
- Initial USB4 DP tunnelling support
- Aldebaran MCE support
- Modifier support for DCC image stores for GFX 10.3
- Display rework for better FP code handling
- Yellow Carp/Cyan Skillfish updates
- Cyan Skillfish display support
- convert vega/navi to IP discovery asic enumeration
- validate IP discovery table
- RAS improvements
- Lots of fixes
i915:
- DG1 PCI IDs + LMEM discovery/placement
- DG1 GuC submission by default
- ADL-S PCI IDs updated + enabled by default
- ADL-P (XE_LPD) fixed and updates
- DG2 display fixes
- PXP protected object support for Gen12 integrated
- expose multi-LRC submission interface for GuC
- export logical engine instance to user
- Disable engine bonding on Gen12+
- PSR cleanup
- PSR2 selective fetch by default
- DP 2.0 prep work
- VESA vendor block + MSO use of it
- FBC refactor
- try again to fix fast-narrow vs slow-wide eDP training
- use THP when IOMMU enabled
- LMEM backup/restore for suspend/resume
- locking simplification
- GuC major reworking
- async flip VT-D workaround changes
- DP link training improvements
- misc display refactorings
bochs:
- new PCI ID
rcar-du:
- Non-contiguious buffer import support for rcar-du
- r8a779a0 support prep
omapdrm:
- COMPILE_TEST fixes
sti:
- COMPILE_TEST fixes
msm:
- fence ordering improvements
- eDP support in DP sub-driver
- dpu irq handling cleanup
- CRC support for making igt happy
- NO_CONNECTOR bridge support
- dsi: 14nm phy support for msm8953
- mdp5: msm8x53, sdm450, sdm632 support
stm:
- layer alpha + zpo support
v3d:
- fix Vulkan CTS failure
- support multiple sync objects
gud:
- add R8/RGB332/RGB888 pixel formats
vc4:
- convert to new bridge helpers
vgem:
- use shmem helpers
virtio:
- support mapping exported vram
zte:
- remove obsolete driver
rockchip:
- use bridge attach no connector for LVDS/RGB"
* tag 'drm-next-2021-11-03' of git://anongit.freedesktop.org/drm/drm: (1259 commits)
drm/amdgpu/gmc6: fix DMA mask from 44 to 40 bits
drm/amd/display: MST support for DPIA
drm/amdgpu: Fix even more out of bound writes from debugfs
drm/amdgpu/discovery: add SDMA IP instance info for soc15 parts
drm/amdgpu/discovery: add UVD/VCN IP instance info for soc15 parts
drm/amdgpu/UAPI: rearrange header to better align related items
drm/amd/display: Enable dpia in dmub only for DCN31 B0
drm/amd/display: Fix USB4 hot plug crash issue
drm/amd/display: Fix deadlock when falling back to v2 from v3
drm/amd/display: Fallback to clocks which meet requested voltage on DCN31
drm/amd/display: move FPU associated DCN301 code to DML folder
drm/amd/display: fix link training regression for 1 or 2 lane
drm/amd/display: add two lane settings training options
drm/amd/display: decouple hw_lane_settings from dpcd_lane_settings
drm/amd/display: implement decide lane settings
drm/amd/display: adopt DP2.0 LT SCR revision 8
drm/amd/display: FEC configuration for dpia links in MST mode
drm/amd/display: FEC configuration for dpia links
drm/amd/display: Add workaround flag for EDID read on certain docks
drm/amd/display: Set phy_mux_sel bit in dmub scratch register
...
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Pull KVM updates from Paolo Bonzini:
"ARM:
- More progress on the protected VM front, now with the full fixed
feature set as well as the limitation of some hypercalls after
initialisation.
- Cleanup of the RAZ/WI sysreg handling, which was pointlessly
complicated
- Fixes for the vgic placement in the IPA space, together with a
bunch of selftests
- More memcg accounting of the memory allocated on behalf of a guest
- Timer and vgic selftests
- Workarounds for the Apple M1 broken vgic implementation
- KConfig cleanups
- New kvmarm.mode=none option, for those who really dislike us
RISC-V:
- New KVM port.
x86:
- New API to control TSC offset from userspace
- TSC scaling for nested hypervisors on SVM
- Switch masterclock protection from raw_spin_lock to seqcount
- Clean up function prototypes in the page fault code and avoid
repeated memslot lookups
- Convey the exit reason to userspace on emulation failure
- Configure time between NX page recovery iterations
- Expose Predictive Store Forwarding Disable CPUID leaf
- Allocate page tracking data structures lazily (if the i915 KVM-GT
functionality is not compiled in)
- Cleanups, fixes and optimizations for the shadow MMU code
s390:
- SIGP Fixes
- initial preparations for lazy destroy of secure VMs
- storage key improvements/fixes
- Log the guest CPNC
Starting from this release, KVM-PPC patches will come from Michael
Ellerman's PPC tree"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits)
RISC-V: KVM: fix boolreturn.cocci warnings
RISC-V: KVM: remove unneeded semicolon
RISC-V: KVM: Fix GPA passed to __kvm_riscv_hfence_gvma_xyz() functions
RISC-V: KVM: Factor-out FP virtualization into separate sources
KVM: s390: add debug statement for diag 318 CPNC data
KVM: s390: pv: properly handle page flags for protected guests
KVM: s390: Fix handle_sske page fault handling
KVM: x86: SGX must obey the KVM_INTERNAL_ERROR_EMULATION protocol
KVM: x86: On emulation failure, convey the exit reason, etc. to userspace
KVM: x86: Get exit_reason as part of kvm_x86_ops.get_exit_info
KVM: x86: Clarify the kvm_run.emulation_failure structure layout
KVM: s390: Add a routine for setting userspace CPU state
KVM: s390: Simplify SIGP Set Arch handling
KVM: s390: pv: avoid stalls when making pages secure
KVM: s390: pv: avoid stalls for kvm_s390_pv_init_vm
KVM: s390: pv: avoid double free of sida page
KVM: s390: pv: add macros for UVC CC values
s390/mm: optimize reset_guest_reference_bit()
s390/mm: optimize set_guest_storage_key()
s390/mm: no need for pte_alloc_map_lock() if we know the pmd is present
...
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git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:
- Initial patch set for Hyper-V isolation VM support (Tianyu Lan)
- Fix a warning on preemption (Vitaly Kuznetsov)
- A bunch of misc cleanup patches
* tag 'hyperv-next-signed-20211102' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Protect set_hv_tscchange_cb() against getting preempted
Drivers: hv : vmbus: Adding NULL pointer check
x86/hyperv: Remove duplicate include
x86/hyperv: Remove duplicated include in hv_init
Drivers: hv: vmbus: Remove unused code to check for subchannels
Drivers: hv: vmbus: Initialize VMbus ring buffer for Isolation VM
Drivers: hv: vmbus: Add SNP support for VMbus channel initiate message
x86/hyperv: Add ghcb hvcall support for SNP VM
x86/hyperv: Add Write/Read MSR registers via ghcb page
Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM
x86/hyperv: Add new hvcall guest address host visibility support
x86/hyperv: Initialize shared memory boundary in the Isolation VM.
x86/hyperv: Initialize GHCB page in Isolation VM
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Do not #GP on userspace use of CLI/STI but pretend it was a NOP to
keep old userspace from breaking. Adjust the corresponding iopl
selftest to that.
- Improve stack overflow warnings to say which stack got overflowed and
raise the exception stack sizes to 2 pages since overflowing the
single page of exception stack is very easy to do nowadays with all
the tracing machinery enabled. With that, rip out the custom mapping
of AMD SEV's too.
- A bunch of changes in preparation for FGKASLR like supporting more
than 64K section headers in the relocs tool, correct ORC lookup table
size to cover the whole kernel .text and other adjustments.
* tag 'x86_core_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86/iopl: Adjust to the faked iopl CLI/STI usage
vmlinux.lds.h: Have ORC lookup cover entire _etext - _stext
x86/boot/compressed: Avoid duplicate malloc() implementations
x86/boot: Allow a "silent" kaslr random byte fetch
x86/tools/relocs: Support >64K section headers
x86/sev: Make the #VC exception stacks part of the default stacks storage
x86: Increase exception stack sizes
x86/mm/64: Improve stack overflow warnings
x86/iopl: Fake iopl(3) CLI/STI usage
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Put the definitions of the hypercalls usable only by pv guests inside
CONFIG_XEN_PV sections.
On Arm two dummy functions related to pv hypercalls can be removed.
While at it remove the no longer supported tmem hypercall definition.
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211028081221.2475-3-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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There are some remaining 32-bit pv-guest support leftovers in the Xen
hypercall interface. Remove them.
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211028081221.2475-2-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.
Currently PCI backend implements multiple functionalities at a time,
such as:
1. It is used as a database for assignable PCI devices, e.g. xl
pci-assignable-{add|remove|list} manipulates that list. So, whenever
the toolstack needs to know which PCI devices can be passed through
it reads that from the relevant sysfs entries of the pciback.
2. It is used to hold the unbound PCI devices list, e.g. when passing
through a PCI device it needs to be unbound from the relevant device
driver and bound to pciback (strictly speaking it is not required
that the device is bound to pciback, but pciback is again used as a
database of the passed through PCI devices, so we can re-bind the
devices back to their original drivers when guest domain shuts down)
3. Device reset for the devices being passed through
4. Para-virtualised use-cases support
The para-virtualised part of the driver is not always needed as some
architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
model for PCI device passthrough.
For such use-cases make the very first step in splitting the
xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
drivers.
For that add new configuration options CONFIG_XEN_PCI_STUB and
CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
functionality, e.g. no support for para-virtualised scenario.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
fully featured backend driver.
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211028143620.144936-1-andr2000@gmail.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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The initial pvops functions handling irq flags will only ever be called
before interrupts are being enabled.
So switch them to be dummy functions:
- xen_save_fl() can always return 0
- xen_irq_disable() is a nop
- xen_irq_enable() can BUG()
Add some generic paravirt functions for that purpose.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20211028072748.29862-3-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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xen_pvh_init() is lacking a prototype in a header, add it.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211006061950.9227-1-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- kprobes: Restructured stack unwinder to show properly on x86 when a
stack dump happens from a kretprobe callback.
- Fix to bootconfig parsing
- Have tracefs allow owner and group permissions by default (only
denying others). There's been pressure to allow non root to tracefs
in a controlled fashion, and using groups is probably the safest.
- Bootconfig memory managament updates.
- Bootconfig clean up to have the tools directory be less dependent on
changes in the kernel tree.
- Allow perf to be traced by function tracer.
- Rewrite of function graph tracer to be a callback from the function
tracer instead of having its own trampoline (this change will happen
on an arch by arch basis, and currently only x86_64 implements it).
- Allow multiple direct trampolines (bpf hooks to functions) be batched
together in one synchronization.
- Allow histogram triggers to add variables that can perform
calculations against the event's fields.
- Use the linker to determine architecture callbacks from the ftrace
trampoline to allow for proper parameter prototypes and prevent
warnings from the compiler.
- Extend histogram triggers to key off of variables.
- Have trace recursion use bit magic to determine preempt context over
if branches.
- Have trace recursion disable preemption as all use cases do anyway.
- Added testing for verification of tracing utilities.
- Various small clean ups and fixes.
* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
tracing/histogram: Fix semicolon.cocci warnings
tracing/histogram: Fix documentation inline emphasis warning
tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
tracing: Show size of requested perf buffer
bootconfig: Initialize ret in xbc_parse_tree()
ftrace: do CPU checking after preemption disabled
ftrace: disable preemption when recursion locked
tracing/histogram: Document expression arithmetic and constants
tracing/histogram: Optimize division by a power of 2
tracing/histogram: Covert expr to const if both operands are constants
tracing/histogram: Simplify handling of .sym-offset in expressions
tracing: Fix operator precedence for hist triggers expression
tracing: Add division and multiplication support for hist triggers
tracing: Add support for creating hist trigger variables from literal
selftests/ftrace: Stop tracing while reading the trace file by default
MAINTAINERS: Update KPROBES and TRACING entries
test_kprobes: Move it from kernel/ to lib/
docs, kprobes: Remove invalid URL and add new reference
samples/kretprobes: Fix return value if register_kretprobe() failed
lib/bootconfig: Fix the xbc_get_info kerneldoc
...
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull thread_info update to move 'cpu' back from task_struct from Kees Cook:
"Cross-architecture update to move task_struct::cpu back into
thread_info on arm64, x86, s390, powerpc, and riscv. All Acked by arch
maintainers.
Quoting Ard Biesheuvel:
'Move task_struct::cpu back into thread_info
Keeping CPU in task_struct is problematic for architectures that
define raw_smp_processor_id() in terms of this field, as it
requires linux/sched.h to be included, which causes a lot of pain
in terms of circular dependencies (aka 'header soup')
This series moves it back into thread_info (where it came from)
for all architectures that enable THREAD_INFO_IN_TASK, addressing
the header soup issue as well as some pointless differences in the
implementations of task_cpu() and set_task_cpu()'"
* tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
riscv: rely on core code to keep thread_info::cpu updated
powerpc: smp: remove hack to obtain offset of task_struct::cpu
sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y
powerpc: add CPU field to struct thread_info
s390: add CPU field to struct thread_info
x86: add CPU field to struct thread_info
arm64: add CPU field to struct thread_info
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Export sev_es_ghcb_hv_call() so that HyperV Isolation VMs can use it
too
- Non-urgent fixes and cleanups
* tag 'x86_sev_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV
x86/sev: Allow #VC exceptions on the VC2 stack
x86/sev: Fix stack type check in vc_switch_off_ist()
x86/sme: Use #define USE_EARLY_PGTABLE_L5 in mem_encrypt_identity.c
x86/sev: Carve out HV call's return value verification
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Start checking a CPUID bit on AMD Zen3 which states that the CPU
clears the segment base when a null selector is written. Do the
explicit detection on older CPUs, zen2 and hygon specifically, which
have the functionality but do not advertize the CPUID bit. Factor in
the presence of a hypervisor underneath the kernel and avoid doing
the explicit check there which the HV might've decided to not
advertize for migration safety reasons, or similar.
- Add support for a new X86 CPU vendor: VORTEX. Needed for whitelisting
those CPUs in the hardware vulnerabilities detection
- Force the compiler to use rIP-relative addressing in the fallback
path of static_cpu_has(), in order to avoid unnecessary register
pressure
* tag 'x86_cpu_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Fix migration safety with X86_BUG_NULL_SEL
x86/CPU: Add support for Vortex CPUs
x86/umip: Downgrade warning messages to debug loglevel
x86/asm: Avoid adding register pressure for the init case in static_cpu_has()
x86/asm: Add _ASM_RIP() macro for x86-64 (%rip) suffix
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Borislav Petkov:
"The usual round of random minor fixes and cleanups all over the place"
* tag 'x86_cleanups_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/Makefile: Remove unneeded whitespaces before tabs
x86/of: Kill unused early_init_dt_scan_chosen_arch()
x86: Fix misspelled Kconfig symbols
x86/Kconfig: Remove references to obsolete Kconfig symbols
x86/smp: Remove unnecessary assignment to local var freq_scale
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull generic confidential computing updates from Borislav Petkov:
"Add an interface called cc_platform_has() which is supposed to be used
by confidential computing solutions to query different aspects of the
system.
The intent behind it is to unify testing of such aspects instead of
having each confidential computing solution add its own set of tests
to code paths in the kernel, leading to an unwieldy mess"
* tag 'x86_cc_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide: Replace the use of mem_encrypt_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_es_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_active() with cc_platform_has()
x86/sme: Replace occurrences of sme_active() with cc_platform_has()
powerpc/pseries/svm: Add a powerpc version of cc_platform_has()
x86/sev: Add an x86 version of cc_platform_has()
arch/cc: Introduce a function to check for confidential computing features
x86/ioremap: Selectively build arch override encryption functions
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS updates from Borislav Petkov:
- Get rid of a bunch of function pointers used in MCA land in favor of
normal functions. This is in preparation of making the MCA code
noinstr-aware
- When the kernel copies data from user addresses and it encounters a
machine check, a SIGBUS is sent to that process. Change this action
to either an -EFAULT which is returned to the user or a short write,
making the recovery action a lot more user-friendly
* tag 'ras_core_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Sort mca_config members to get rid of unnecessary padding
x86/mce: Get rid of the ->quirk_no_way_out() indirect call
x86/mce: Get rid of msr_ops
x86/mce: Get rid of machine_check_vector
x86/mce: Get rid of the mce_severity function pointer
x86/mce: Drop copyin special case for #MC
x86/mce: Change to not send SIGBUS error during copy from user
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu updates from Thomas Gleixner:
- Cleanup of extable fixup handling to be more robust, which in turn
allows to make the FPU exception fixups more robust as well.
- Change the return code for signal frame related failures from
explicit error codes to a boolean fail/success as that's all what the
calling code evaluates.
- A large refactoring of the FPU code to prepare for adding AMX
support:
- Distangle the public header maze and remove especially the
misnomed kitchen sink internal.h which is despite it's name
included all over the place.
- Add a proper abstraction for the register buffer storage (struct
fpstate) which allows to dynamically size the buffer at runtime
by flipping the pointer to the buffer container from the default
container which is embedded in task_struct::tread::fpu to a
dynamically allocated container with a larger register buffer.
- Convert the code over to the new fpstate mechanism.
- Consolidate the KVM FPU handling by moving the FPU related code
into the FPU core which removes the number of exports and avoids
adding even more export when AMX has to be supported in KVM.
This also removes duplicated code which was of course
unnecessary different and incomplete in the KVM copy.
- Simplify the KVM FPU buffer handling by utilizing the new
fpstate container and just switching the buffer pointer from the
user space buffer to the KVM guest buffer when entering
vcpu_run() and flipping it back when leaving the function. This
cuts the memory requirements of a vCPU for FPU buffers in half
and avoids pointless memory copy operations.
This also solves the so far unresolved problem of adding AMX
support because the current FPU buffer handling of KVM inflicted
a circular dependency between adding AMX support to the core and
to KVM. With the new scheme of switching fpstate AMX support can
be added to the core code without affecting KVM.
- Replace various variables with proper data structures so the
extra information required for adding dynamically enabled FPU
features (AMX) can be added in one place
- Add AMX (Advanced Matrix eXtensions) support (finally):
AMX is a large XSTATE component which is going to be available with
Saphire Rapids XEON CPUs. The feature comes with an extra MSR
(MSR_XFD) which allows to trap the (first) use of an AMX related
instruction, which has two benefits:
1) It allows the kernel to control access to the feature
2) It allows the kernel to dynamically allocate the large register
state buffer instead of burdening every task with the the extra
8K or larger state storage.
It would have been great to gain this kind of control already with
AVX512.
The support comes with the following infrastructure components:
1) arch_prctl() to
- read the supported features (equivalent to XGETBV(0))
- read the permitted features for a task
- request permission for a dynamically enabled feature
Permission is granted per process, inherited on fork() and
cleared on exec(). The permission policy of the kernel is
restricted to sigaltstack size validation, but the syscall
obviously allows further restrictions via seccomp etc.
2) A stronger sigaltstack size validation for sys_sigaltstack(2)
which takes granted permissions and the potentially resulting
larger signal frame into account. This mechanism can also be used
to enforce factual sigaltstack validation independent of dynamic
features to help with finding potential victims of the 2K
sigaltstack size constant which is broken since AVX512 support
was added.
3) Exception handling for #NM traps to catch first use of a extended
feature via a new cause MSR. If the exception was caused by the
use of such a feature, the handler checks permission for that
feature. If permission has not been granted, the handler sends a
SIGILL like the #UD handler would do if the feature would have
been disabled in XCR0. If permission has been granted, then a new
fpstate which fits the larger buffer requirement is allocated.
In the unlikely case that this allocation fails, the handler
sends SIGSEGV to the task. That's not elegant, but unavoidable as
the other discussed options of preallocation or full per task
permissions come with their own set of horrors for kernel and/or
userspace. So this is the lesser of the evils and SIGSEGV caused
by unexpected memory allocation failures is not a fundamentally
new concept either.
When allocation succeeds, the fpstate properties are filled in to
reflect the extended feature set and the resulting sizes, the
fpu::fpstate pointer is updated accordingly and the trap is
disarmed for this task permanently.
4) Enumeration and size calculations
5) Trap switching via MSR_XFD
The XFD (eXtended Feature Disable) MSR is context switched with
the same life time rules as the FPU register state itself. The
mechanism is keyed off with a static key which is default
disabled so !AMX equipped CPUs have zero overhead. On AMX enabled
CPUs the overhead is limited by comparing the tasks XFD value
with a per CPU shadow variable to avoid redundant MSR writes. In
case of switching from a AMX using task to a non AMX using task
or vice versa, the extra MSR write is obviously inevitable.
All other places which need to be aware of the variable feature
sets and resulting variable sizes are not affected at all because
they retrieve the information (feature set, sizes) unconditonally
from the fpstate properties.
6) Enable the new AMX states
Note, this is relatively new code despite the fact that AMX support
is in the works for more than a year now.
The big refactoring of the FPU code, which allowed to do a proper
integration has been started exactly 3 weeks ago. Refactoring of the
existing FPU code and of the original AMX patches took a week and has
been subject to extensive review and testing. The only fallout which
has not been caught in review and testing right away was restricted
to AMX enabled systems, which is completely irrelevant for anyone
outside Intel and their early access program. There might be dragons
lurking as usual, but so far the fine grained refactoring has held up
and eventual yet undetected fallout is bisectable and should be
easily addressable before the 5.16 release. Famous last words...
Many thanks to Chang Bae and Dave Hansen for working hard on this and
also to the various test teams at Intel who reserved extra capacity
to follow the rapid development of this closely which provides the
confidence level required to offer this rather large update for
inclusion into 5.16-rc1
* tag 'x86-fpu-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
Documentation/x86: Add documentation for using dynamic XSTATE features
x86/fpu: Include vmalloc.h for vzalloc()
selftests/x86/amx: Add context switch test
selftests/x86/amx: Add test cases for AMX state management
x86/fpu/amx: Enable the AMX feature in 64-bit mode
x86/fpu: Add XFD handling for dynamic states
x86/fpu: Calculate the default sizes independently
x86/fpu/amx: Define AMX state components and have it used for boot-time checks
x86/fpu/xstate: Prepare XSAVE feature table for gaps in state component numbers
x86/fpu/xstate: Add fpstate_realloc()/free()
x86/fpu/xstate: Add XFD #NM handler
x86/fpu: Update XFD state where required
x86/fpu: Add sanity checks for XFD
x86/fpu: Add XFD state to fpstate
x86/msr-index: Add MSRs for XFD
x86/cpufeatures: Add eXtended Feature Disabling (XFD) feature bit
x86/fpu: Reset permission and fpstate on exec()
x86/fpu: Prepare fpu_clone() for dynamically enabled features
x86/fpu/signal: Prepare for variable sigframe length
x86/signal: Use fpu::__state_user_size for sigalt stack validation
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:
- Revert the printk format based wchan() symbol resolution as it can
leak the raw value in case that the symbol is not resolvable.
- Make wchan() more robust and work with all kind of unwinders by
enforcing that the task stays blocked while unwinding is in progress.
- Prevent sched_fork() from accessing an invalid sched_task_group
- Improve asymmetric packing logic
- Extend scheduler statistics to RT and DL scheduling classes and add
statistics for bandwith burst to the SCHED_FAIR class.
- Properly account SCHED_IDLE entities
- Prevent a potential deadlock when initial priority is assigned to a
newly created kthread. A recent change to plug a race between cpuset
and __sched_setscheduler() introduced a new lock dependency which is
now triggered. Break the lock dependency chain by moving the priority
assignment to the thread function.
- Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
- Improve idle balancing in general and especially for NOHZ enabled
systems.
- Provide proper interfaces for live patching so it does not have to
fiddle with scheduler internals.
- Add cluster aware scheduling support.
- A small set of tweaks for RT (irqwork, wait_task_inactive(), various
scheduler options and delaying mmdrop)
- The usual small tweaks and improvements all over the place
* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
sched/fair: Cleanup newidle_balance
sched/fair: Remove sysctl_sched_migration_cost condition
sched/fair: Wait before decaying max_newidle_lb_cost
sched/fair: Skip update_blocked_averages if we are defering load balance
sched/fair: Account update_blocked_averages in newidle_balance cost
x86: Fix __get_wchan() for !STACKTRACE
sched,x86: Fix L2 cache mask
sched/core: Remove rq_relock()
sched: Improve wake_up_all_idle_cpus() take #2
irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
sched: Add cluster scheduler level for x86
sched: Add cluster scheduler level in core and related Kconfig for ARM64
topology: Represent clusters of CPUs within a die
sched: Disable -Wunused-but-set-variable
sched: Add wrapper for get_wchan() to keep task blocked
x86: Fix get_wchan() to support the ORC unwinder
proc: Use task_is_running() for wchan in /proc/$pid/stat
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool updates from Thomas Gleixner:
- Improve retpoline code patching by separating it from alternatives
which reduces memory footprint and allows to do better optimizations
in the actual runtime patching.
- Add proper retpoline support for x86/BPF
- Address noinstr warnings in x86/kvm, lockdep and paravirtualization
code
- Add support to handle pv_opsindirect calls in the noinstr analysis
- Classify symbols upfront and cache the result to avoid redundant
str*cmp() invocations.
- Add a CFI hash to reduce memory consumption which also reduces
runtime on a allyesconfig by ~50%
- Adjust XEN code to make objtool handling more robust and as a side
effect to prevent text fragmentation due to placement of the
hypercall page.
* tag 'objtool-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
bpf,x86: Respect X86_FEATURE_RETPOLINE*
bpf,x86: Simplify computing label offsets
x86,bugs: Unconditionally allow spectre_v2=retpoline,amd
x86/alternative: Add debug prints to apply_retpolines()
x86/alternative: Try inline spectre_v2=retpoline,amd
x86/alternative: Handle Jcc __x86_indirect_thunk_\reg
x86/alternative: Implement .retpoline_sites support
x86/retpoline: Create a retpoline thunk array
x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h
x86/asm: Fixup odd GEN-for-each-reg.h usage
x86/asm: Fix register order
x86/retpoline: Remove unused replacement symbols
objtool,x86: Replace alternatives with .retpoline_sites
objtool: Shrink struct instruction
objtool: Explicitly avoid self modifying code in .altinstr_replacement
objtool: Classify symbols
objtool: Support pv_opsindirect calls for noinstr
x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays
x86/xen: Mark xen_force_evtchn_callback() noinstr
x86/xen: Make irq_disable() noinstr
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
"Updates for the interrupt subsystem:
Core changes:
- Prevent a potential deadlock when initial priority is assigned to a
newly created interrupt thread. A recent change to plug a race
between cpuset and __sched_setscheduler() introduced a new lock
dependency which is now triggered. Break the lock dependency chain
by moving the priority assignment to the thread function.
- A couple of small updates to make the irq core RT safe.
- Confine the irq_cpu_online/offline() API to the only left unfixable
user Cavium Octeon so that it does not grow new usage.
- A small documentation update
Driver changes:
- A large cross architecture rework to move irq_enter/exit() into the
architecture code to make addressing the NOHZ_FULL/RCU issues
simpler.
- The obligatory new irq chip driver for Microchip EIC
- Modularize a few irq chip drivers
- Expand usage of devm_*() helpers throughout the driver code
- The usual small fixes and improvements all over the place"
* tag 'irq-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
h8300: Fix linux/irqchip.h include mess
dt-bindings: irqchip: renesas-irqc: Document r8a774e1 bindings
MIPS: irq: Avoid an unused-variable error
genirq: Hide irq_cpu_{on,off}line() behind a deprecated option
irqchip/mips-gic: Get rid of the reliance on irq_cpu_online()
MIPS: loongson64: Drop call to irq_cpu_offline()
irq: remove handle_domain_{irq,nmi}()
irq: remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: riscv: perform irqentry in entry code
irq: openrisc: perform irqentry in entry code
irq: csky: perform irqentry in entry code
irq: arm64: perform irqentry in entry code
irq: arm: perform irqentry in entry code
irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: nds32: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: add generic_handle_arch_irq()
irq: unexport handle_irq_desc()
irq: simplify handle_domain_{irq,nmi}()
irq: mips: simplify do_domain_IRQ()
...
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'arm/tegra', 'iommu/fixes', 'x86/amd', 'x86/vt-d' and 'core' into next
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Pull kvm fixes from Paolo Bonzini:
- Fixes for s390 interrupt delivery
- Fixes for Xen emulator bugs showing up as debug kernel WARNs
- Fix another issue with SEV/ES string I/O VMGEXITs
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Take srcu lock in post_kvm_run_save()
KVM: SEV-ES: fix another issue with string I/O VMGEXITs
KVM: x86/xen: Fix kvm_xen_has_interrupt() sleeping in kvm_vcpu_block()
KVM: x86: switch pvclock_gtod_sync_lock to a raw spinlock
KVM: s390: preserve deliverable_mask in __airqs_kick_single_vcpu
KVM: s390: clear kicked_mask before sleeping again
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for Linux 5.16
- More progress on the protected VM front, now with the full
fixed feature set as well as the limitation of some hypercalls
after initialisation.
- Cleanup of the RAZ/WI sysreg handling, which was pointlessly
complicated
- Fixes for the vgic placement in the IPA space, together with a
bunch of selftests
- More memcg accounting of the memory allocated on behalf of a guest
- Timer and vgic selftests
- Workarounds for the Apple M1 broken vgic implementation
- KConfig cleanups
- New kvmarm.mode=none option, for those who really dislike us
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Merge irqchip updates for Linux 5.16 from Marc Zyngier:
- A large cross-arch rework to move irq_enter()/irq_exit() into
the arch code, and removing it from the generic irq code.
Thanks to Mark Rutland for the huge effort!
- A few irqchip drivers are made modular (broadcom, meson), because
that's apparently a thing...
- A new driver for the Microchip External Interrupt Controller
- The irq_cpu_offline()/irq_cpu_online() API is now deprecated and
can only be selected on the Cavium Octeon platform. Once this
platform is removed, the API will be removed at the same time.
- A sprinkle of devm_* helper, as people seem to love that.
- The usual spattering of small fixes and minor improvements.
* tag 'irqchip-5.16': (912 commits)
h8300: Fix linux/irqchip.h include mess
dt-bindings: irqchip: renesas-irqc: Document r8a774e1 bindings
MIPS: irq: Avoid an unused-variable error
genirq: Hide irq_cpu_{on,off}line() behind a deprecated option
irqchip/mips-gic: Get rid of the reliance on irq_cpu_online()
MIPS: loongson64: Drop call to irq_cpu_offline()
irq: remove handle_domain_{irq,nmi}()
irq: remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: riscv: perform irqentry in entry code
irq: openrisc: perform irqentry in entry code
irq: csky: perform irqentry in entry code
irq: arm64: perform irqentry in entry code
irq: arm: perform irqentry in entry code
irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
irq: nds32: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ
irq: add generic_handle_arch_irq()
irq: unexport handle_irq_desc()
irq: simplify handle_domain_{irq,nmi}()
irq: mips: simplify do_domain_IRQ()
...
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211029083332.3680101-1-maz@kernel.org
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Current BPF codegen doesn't respect X86_FEATURE_RETPOLINE* flags and
unconditionally emits a thunk call, this is sub-optimal and doesn't
match the regular, compiler generated, code.
Update the i386 JIT to emit code equal to what the compiler emits for
the regular kernel text (IOW. a plain THUNK call).
Update the x86_64 JIT to emit code similar to the result of compiler
and kernel rewrites as according to X86_FEATURE_RETPOLINE* flags.
Inlining RETPOLINE_AMD (lfence; jmp *%reg) and !RETPOLINE (jmp *%reg),
while doing a THUNK call for RETPOLINE.
This removes the hard-coded retpoline thunks and shrinks the generated
code. Leaving a single retpoline thunk definition in the kernel.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.614772675@infradead.org
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Rewrite retpoline thunk call sites to be indirect calls for
spectre_v2=off. This ensures spectre_v2=off is as near to a
RETPOLINE=n build as possible.
This is the replacement for objtool writing alternative entries to
ensure the same and achieves feature-parity with the previous
approach.
One noteworthy feature is that it relies on the thunks to be in
machine order to compute the register index.
Specifically, this does not yet address the Jcc __x86_indirect_thunk_*
calls generated by clang, a future patch will add this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.232495794@infradead.org
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Stick all the retpolines in a single symbol and have the individual
thunks as inner labels, this should guarantee thunk order and layout.
Previously there were 16 (or rather 15 without rsp) separate symbols and
a toolchain might reasonably expect it could displace them however it
liked, with disregard for their relative position.
However, now they're part of a larger symbol. Any change to their
relative position would disrupt this larger _array symbol and thus not
be sound.
This is the same reasoning used for data symbols. On their own there
is no guarantee about their relative position wrt to one aonther, but
we're still able to do arrays because an array as a whole is a single
larger symbol.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.169659320@infradead.org
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Because it makes no sense to split the retpoline gunk over multiple
headers.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211026120310.106290934@infradead.org
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