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2021-11-15x86/hyperv: Move required MSRs check to initial platform probingSean Christopherson
Explicitly check for MSR_HYPERCALL and MSR_VP_INDEX support when probing for running as a Hyper-V guest instead of waiting until hyperv_init() to detect the bogus configuration. Add messages to give the admin a heads up that they are likely running on a broken virtual machine setup. At best, silently disabling Hyper-V is confusing and difficult to debug, e.g. the kernel _says_ it's using all these fancy Hyper-V features, but always falls back to the native versions. At worst, the half baked setup will crash/hang the kernel. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20211104182239.1302956-3-seanjc@google.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28x86/hyperv: Initialize shared memory boundary in the Isolation VM.Tianyu Lan
Hyper-V exposes shared memory boundary via cpuid HYPERV_CPUID_ISOLATION_CONFIG and store it in the shared_gpa_boundary of ms_hyperv struct. This prepares to share memory with host for SNP guest. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-3-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-10-28x86/hyperv: Initialize GHCB page in Isolation VMTianyu Lan
Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest to communicate with hypervisor. Map GHCB page for all cpus to read/write MSR register and submit hvcall request via ghcb page. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-09-01Merge tag 'hyperv-next-signed-20210831' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv updates from Wei Liu: - make Hyper-V code arch-agnostic (Michael Kelley) - fix sched_clock behaviour on Hyper-V (Ani Sinha) - fix a fault when Linux runs as the root partition on MSHV (Praveen Kumar) - fix VSS driver (Vitaly Kuznetsov) - cleanup (Sonia Sharma) * tag 'hyperv-next-signed-20210831' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: hv_utils: Set the maximum packet size for VSS driver to the length of the receive buffer Drivers: hv: Enable Hyper-V code to be built on ARM64 arm64: efi: Export screen_info arm64: hyperv: Initialize hypervisor on boot arm64: hyperv: Add panic handler arm64: hyperv: Add Hyper-V hypercall and register access utilities x86/hyperv: fix root partition faults when writing to VP assist page MSR hv: hyperv.h: Remove unused inline functions drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers x86/hyperv: add comment describing TSC_INVARIANT_CONTROL MSR setting bit 0 Drivers: hv: Move Hyper-V misc functionality to arch-neutral code Drivers: hv: Add arch independent default functions for some Hyper-V handlers Drivers: hv: Make portions of Hyper-V init code be arch neutral x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked unstable asm-generic/hyperv: Add missing #include of nmi.h
2021-07-21Revert "x86/hyperv: fix logical processor creation"Wei Liu
This reverts commit 450605c28d571eddca39a65fdbc1338add44c6d9. Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-16x86/hyperv: add comment describing TSC_INVARIANT_CONTROL MSR setting bit 0Ani Sinha
Commit dce7cd62754b5 ("x86/hyperv: Allow guests to enable InvariantTSC") added the support for HV_X64_MSR_TSC_INVARIANT_CONTROL. Setting bit 0 of this synthetic MSR will allow hyper-v guests to report invariant TSC CPU feature through CPUID. This comment adds this explanation to the code and mentions where the Intel's generic platform init code reads this feature bit from CPUID. The comment will help developers understand how the two parts of the initialization (hyperV specific and non-hyperV specific generic hw init) are related. Signed-off-by: Ani Sinha <ani@anisinha.ca> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210716133245.3272672-1-ani@anisinha.ca Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15Drivers: hv: Move Hyper-V misc functionality to arch-neutral codeMichael Kelley
The check for whether hibernation is possible, and the enabling of Hyper-V panic notification during kexec, are both architecture neutral. Move the code from under arch/x86 and into drivers/hv/hv_common.c where it can also be used for ARM64. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1626287687-2045-4-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15Drivers: hv: Add arch independent default functions for some Hyper-V handlersMichael Kelley
Architecture independent Hyper-V code calls various arch-specific handlers when needed. To aid in supporting multiple architectures, provide weak defaults that can be overridden by arch-specific implementations where appropriate. But when arch-specific overrides aren't needed or haven't been implemented yet for a particular architecture, these stubs reduce the amount of clutter under arch/. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1626287687-2045-3-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-15Drivers: hv: Make portions of Hyper-V init code be arch neutralMichael Kelley
The code to allocate and initialize the hv_vp_index array is architecture neutral. Similarly, the code to allocate and populate the hypercall input and output arg pages is architecture neutral. Move both sets of code out from arch/x86 and into utility functions in drivers/hv/hv_common.c that can be shared by Hyper-V initialization on ARM64. No functional changes. However, the allocation of the hypercall input and output arg pages is done differently so that the size is always the Hyper-V page size, even if not the same as the guest page size (such as with ARM64's 64K page size). Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1626287687-2045-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-13x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked ↵Ani Sinha
unstable Marking TSC as unstable has a side effect of marking sched_clock as unstable when TSC is still being used as the sched_clock. This is not desirable. Hyper-V ultimately uses a paravirtualized clock source that provides a stable scheduler clock even on systems without TscInvariant CPU capability. Hence, mark_tsc_unstable() call should be called _after_ scheduler clock has been changed to the paravirtualized clocksource. This will prevent any unwanted manipulation of the sched_clock. Only TSC will be correctly marked as unstable. Signed-off-by: Ani Sinha <ani@anisinha.ca> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210713030522.1714803-1-ani@anisinha.ca Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-07-02Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...
2021-07-01kernel.h: split out panic and oops helpersAndy Shevchenko
kernel.h is being used as a dump for all kinds of stuff for a long time. Here is the attempt to start cleaning it up by splitting out panic and oops helpers. There are several purposes of doing this: - dropping dependency in bug.h - dropping a loop by moving out panic_notifier.h - unload kernel.h from something which has its own domain At the same time convert users tree-wide to use new headers, although for the time being include new header back to kernel.h to avoid twisted indirected includes for existing users. [akpm@linux-foundation.org: thread_info.h needs limits.h] [andriy.shevchenko@linux.intel.com: ia64 fix] Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Co-developed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Corey Minyard <cminyard@mvista.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Wei Liu <wei.liu@kernel.org> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Sebastian Reichel <sre@kernel.org> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Stephen Boyd <sboyd@kernel.org> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29Merge tag 'hyperv-next-signed-20210629' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv updates from Wei Liu: "Just a few minor enhancement patches and bug fixes" * tag 'hyperv-next-signed-20210629' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: PCI: hv: Add check for hyperv_initialized in init_hv_pci_drv() Drivers: hv: Move Hyper-V extended capability check to arch neutral code drivers: hv: Fix missing error code in vmbus_connect() x86/hyperv: fix logical processor creation hv_utils: Fix passing zero to 'PTR_ERR' warning scsi: storvsc: Use blk_mq_unique_tag() to generate requestIDs Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer hv_balloon: Remove redundant assignment to region_start
2021-06-17hyperv: Detect Nested virtualization support for SVMVineeth Pillai
Previously, to detect nested virtualization enlightenment support, we were using HV_X64_ENLIGHTENED_VMCS_RECOMMENDED feature bit of HYPERV_CPUID_ENLIGHTMENT_INFO.EAX CPUID as docuemented in TLFS: "Bit 14: Recommend a nested hypervisor using the enlightened VMCS interface. Also indicates that additional nested enlightenments may be available (see leaf 0x4000000A)". Enlightened VMCS, however, is an Intel only feature so the above detection method doesn't work for AMD. So, use the HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS.EAX CPUID information ("The maximum input value for hypervisor CPUID information.") and this works for both AMD and Intel. Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Message-Id: <43b25ff21cd2d9a51582033c9bdd895afefac056.1622730232.git.viremana@linux.microsoft.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-02x86/hyperv: fix logical processor creationPraveen Kumar
Microsoft Hypervisor expects the logical processor index to be the same as CPU's index during logical processor creation. Using cpu_physical_id confuses hypervisor's scheduler. That causes the root partition not boot when core scheduler is used. This patch removes the call to cpu_physical_id and uses the CPU index directly for bringing up logical processor. This scheme works for both classic scheduler and core scheduler. Fixes: 333abaf5abb3 (x86/hyperv: implement and use hv_smp_prepare_cpus) Signed-off-by: Praveen Kumar <kumarpraveen@linux.microsoft.com> Link: https://lore.kernel.org/r/20210531074046.113452-1-kumarpraveen@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-04-26Merge tag 'hyperv-next-signed-20210426' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull Hyper-V updates from Wei Liu: - VMBus enhancement - Free page reporting support for Hyper-V balloon driver - Some patches for running Linux as Arm64 Hyper-V guest - A few misc clean-up patches * tag 'hyperv-next-signed-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (30 commits) drivers: hv: Create a consistent pattern for checking Hyper-V hypercall status x86/hyperv: Move hv_do_rep_hypercall to asm-generic video: hyperv_fb: Add ratelimit on error message Drivers: hv: vmbus: Increase wait time for VMbus unload Drivers: hv: vmbus: Initialize unload_event statically Drivers: hv: vmbus: Check for pending channel interrupts before taking a CPU offline Drivers: hv: vmbus: Drivers: hv: vmbus: Introduce CHANNELMSG_MODIFYCHANNEL_RESPONSE Drivers: hv: vmbus: Introduce and negotiate VMBus protocol version 5.3 Drivers: hv: vmbus: Use after free in __vmbus_open() Drivers: hv: vmbus: remove unused function Drivers: hv: vmbus: Remove unused linux/version.h header x86/hyperv: remove unused linux/version.h header x86/Hyper-V: Support for free page reporting x86/hyperv: Fix unused variable 'hi' warning in hv_apic_read x86/hyperv: Fix unused variable 'msr_val' warning in hv_qlock_wait hv: hyperv.h: a few mundane typo fixes drivers: hv: Fix EXPORT_SYMBOL and tab spaces issue Drivers: hv: vmbus: Drop error message when 'No request id available' asm-generic/hyperv: Add missing function prototypes per -W1 warnings clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts ...
2021-03-24x86/Hyper-V: Support for free page reportingSunil Muthuswamy
Linux has support for free page reporting now (36e66c554b5c) for virtualized environment. On Hyper-V when virtually backed VMs are configured, Hyper-V will advertise cold memory discard capability, when supported. This patch adds the support to hook into the free page reporting infrastructure and leverage the Hyper-V cold memory discard hint hypercall to report/free these pages back to the host. Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com> Tested-by: Matheus Castello <matheus@castello.eng.br> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/SN4PR2101MB0880121FA4E2FEC67F35C1DCC0649@SN4PR2101MB0880.namprd21.prod.outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-18x86: Fix various typos in commentsIngo Molnar
Fix ~144 single-word typos in arch/x86/ code comments. Doing this in a single commit should reduce the churn. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-kernel@vger.kernel.org
2021-03-08clocksource/drivers/hyper-v: Move handling of STIMER0 interruptsMichael Kelley
STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interrupt handling machinery is done in code under arch/x86 and Linux IRQs are not used. Adding support for ARM64 means adding equivalent code using per-cpu IRQs under arch/arm64. A better model is to treat per-cpu IRQs as the normal path (which it is for modern architectures), and the x86/x64 path as the exception. Do this by incorporating standard Linux per-cpu IRQ allocation into the main SITMER0 driver code, and bypass it in the x86/x64 exception case. For x86/x64, special case code is retained under arch/x86, but no STIMER0 interrupt handling code is needed under arch/arm64. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/1614721102-2241-11-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-03-08Drivers: hv: vmbus: Move handling of VMbus interruptsMichael Kelley
VMbus interrupts are most naturally modelled as per-cpu IRQs. But because x86/x64 doesn't have per-cpu IRQs, the core VMbus interrupt handling machinery is done in code under arch/x86 and Linux IRQs are not used. Adding support for ARM64 means adding equivalent code using per-cpu IRQs under arch/arm64. A better model is to treat per-cpu IRQs as the normal path (which it is for modern architectures), and the x86/x64 path as the exception. Do this by incorporating standard Linux per-cpu IRQ allocation into the main VMbus driver, and bypassing it in the x86/x64 exception case. For x86/x64, special case code is retained under arch/x86, but no VMbus interrupt handling code is needed under arch/arm64. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/1614721102-2241-7-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-02-11x86/hyperv: implement and use hv_smp_prepare_cpusWei Liu
Microsoft Hypervisor requires the root partition to make a few hypercalls to setup application processors before they can be used. Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com> Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com> Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210203150435.27941-11-wei.liu@kernel.org
2021-02-11x86/hyperv: detect if Linux is the root partitionWei Liu
For now we can use the privilege flag to check. Stash the value to be used later. Put in a bunch of defines for future use when we want to have more fine-grained detection. Signed-off-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210203150435.27941-3-wei.liu@kernel.org
2021-02-11x86/hyperv: Load/save the Isolation Configuration leafAndrea Parri (Microsoft)
If bit 22 of Group B Features is set, the guest has access to the Isolation Configuration CPUID leaf. On x86, the first four bits of EAX in this leaf provide the isolation type of the partition; we entail three isolation types: 'SNP' (hardware-based isolation), 'VBS' (software-based isolation), and 'NONE' (no isolation). Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> 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: Arnd Bergmann <arnd@arndb.de> Cc: x86@kernel.org Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/r/20210201144814.2701-2-parri.andrea@gmail.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2021-01-05x86/hyperv: Fix kexec panic/hang issuesDexuan Cui
Currently the kexec kernel can panic or hang due to 2 causes: 1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the old VP Assist Pages when the kexec kernel runs. The same issue is fixed for hibernation in commit 421f090c819d ("x86/hyperv: Suspend/resume the VP assist page for hibernation"). Now fix it for kexec. 2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so between hv_kexec_handler() and native_machine_shutdown(), the other CPUs can still try to access the hypercall page and cause panic. The workaround "hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move hyperv_cleanup() to a better place. Signed-off-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-11-04x86/hyperv: Enable 15-bit APIC ID if the hypervisor supports itDexuan Cui
When a Linux VM runs on Hyper-V, if the VM has CPUs with >255 APIC IDs, the CPUs can't be the destination of IOAPIC interrupts, because the IOAPIC RTE's Dest Field has only 8 bits. Currently the hackery driver drivers/iommu/hyperv-iommu.c is used to ensure IOAPIC interrupts are only routed to CPUs that don't have >255 APIC IDs. However, there is an issue with kdump, because the kdump kernel can run on any CPU, and hence IOAPIC interrupts can't work if the kdump kernel run on a CPU with a >255 APIC ID. The kdump issue can be fixed by the Extended Dest ID, which is introduced recently by David Woodhouse (for IOAPIC, see the field virt_destid_8_14 in struct IO_APIC_route_entry). Of course, the Extended Dest ID needs the support of the underlying hypervisor. The latest Hyper-V has added the support recently: with this commit, on such a Hyper-V host, Linux VM does not use hyperv-iommu.c because hyperv_prepare_irq_remapping() returns -ENODEV; instead, Linux kernel's generic support of Extended Dest ID from David is used, meaning that Linux VM is able to support up to 32K CPUs, and IOAPIC interrupts can be routed to all the CPUs. On an old Hyper-V host that doesn't support the Extended Dest ID, nothing changes with this commit: Linux VM is still able to bring up the CPUs with > 255 APIC IDs with the help of hyperv-iommu.c, but IOAPIC interrupts still can not go to such CPUs, and the kdump kernel still can not work properly on such CPUs. [ tglx: Updated comment as suggested by David ] Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Link: https://lore.kernel.org/r/20201103011136.59108-1-decui@microsoft.com
2020-10-14Drivers: hv: vmbus: Add parsing of VMbus interrupt in ACPI DSDTMichael Kelley
On ARM64, Hyper-V now specifies the interrupt to be used by VMbus in the ACPI DSDT. This information is not used on x86 because the interrupt vector must be hardcoded. But update the generic VMbus driver to do the parsing and pass the information to the architecture specific code that sets up the Linux IRQ. Update consumers of the interrupt to get it from an architecture specific function. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1597434304-40631-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-09-28x86/hyperv: Remove aliases with X64 in their nameJoseph Salisbury
In the architecture independent version of hyperv-tlfs.h, commit c55a844f46f958b removed the "X64" in the symbol names so they would make sense for both x86 and ARM64. That commit added aliases with the "X64" in the x86 version of hyperv-tlfs.h so that existing x86 code would continue to compile. As a cleanup, update the x86 code to use the symbols without the "X64", then remove the aliases. There's no functional change. Signed-off-by: Joseph Salisbury <joseph.salisbury@microsoft.com> Link: https://lore.kernel.org/r/1601130386-11111-1-git-send-email-jsalisbury@linux.microsoft.com Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-08-11x86/hyperv: Make hv_setup_sched_clock inlineMichael Kelley
Make hv_setup_sched_clock inline so the reference to pv_ops works correctly with objtool updates to detect noinstr violations. See https://lore.kernel.org/patchwork/patch/1283635/ Signed-off-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/1597022991-24088-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-06-11x86/entry: Convert various hypervisor vectors to IDTENTRY_SYSVECThomas Gleixner
Convert various hypervisor vectors to IDTENTRY_SYSVEC: - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC - Remove the ASM idtentries in 64-bit - Remove the BUILD_INTERRUPT entries in 32-bit - Remove the old prototypes No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/20200521202119.647997594@linutronix.de
2020-04-11x86/Hyper-V: Report crash register data or kmsg before running crash kernelTianyu Lan
We want to notify Hyper-V when a Linux guest VM crash occurs, so there is a record of the crash even when kdump is enabled. But crash_kexec_post_notifiers defaults to "false", so the kdump kernel runs before the notifiers and Hyper-V never gets notified. Fix this by always setting crash_kexec_post_notifiers to be true for Hyper-V VMs. Fixes: 81b18bce48af ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic") Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20200406155331.2105-5-Tianyu.Lan@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
2020-04-09x86: hyperv: report value of misc_featuresOlaf Hering
A few kernel features depend on ms_hyperv.misc_features, but unlike its siblings ->features and ->hints, the value was never reported during boot. Signed-off-by: Olaf Hering <olaf@aepfle.de> Link: https://lore.kernel.org/r/20200407172739.31371-1-olaf@aepfle.de Signed-off-by: Wei Liu <wei.liu@kernel.org>
2019-11-15Merge branch 'linus' into x86/hypervThomas Gleixner
Pick up upstream fixes to avoid conflicts.
2019-11-12x86/hyperv: Allow guests to enable InvariantTSCAndrea Parri
If the hardware supports TSC scaling, Hyper-V will set bit 15 of the HV_PARTITION_PRIVILEGE_MASK in guest VMs with a compatible Hyper-V configuration version. Bit 15 corresponds to the AccessTscInvariantControls privilege. If this privilege bit is set, guests can access the HvSyntheticInvariantTscControl MSR: guests can set bit 0 of this synthetic MSR to enable the InvariantTSC feature. After setting the synthetic MSR, CPUID will enumerate support for InvariantTSC. Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lkml.kernel.org/r/20191003155200.22022-1-parri.andrea@gmail.com
2019-10-18x86/hyperv: Set pv_info.name to "Hyper-V"Andrea Parri
Michael reported that the x86/hyperv initialization code prints the following dmesg when running in a VM on Hyper-V: [ 0.000738] Booting paravirtualized kernel on bare hardware Let the x86/hyperv initialization code set pv_info.name to "Hyper-V" so dmesg reports correctly: [ 0.000172] Booting paravirtualized kernel on Hyper-V [ tglx: Folded build fix provided by Yue ] Reported-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Cc: YueHaibing <yuehaibing@huawei.com> Link: https://lkml.kernel.org/r/20191015103502.13156-1-parri.andrea@gmail.com
2019-08-28x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=nTianyu Lan
hv_setup_sched_clock() references pv_ops which is only available when CONFIG_PARAVIRT=Y. Wrap it into a #ifdef Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190828080747.204419-1-Tianyu.Lan@microsoft.com
2019-08-23clocksource/drivers/hyperv: Add Hyper-V specific sched clock functionTianyu Lan
Hyper-V guests use the default native_sched_clock() in pv_ops.time.sched_clock on x86. But native_sched_clock() directly uses the raw TSC value, which can be discontinuous in a Hyper-V VM. Add the generic hv_setup_sched_clock() to set the sched clock function appropriately. On x86, this sets pv_ops.time.sched_clock to read the Hyper-V reference TSC value that is scaled and adjusted to be continuous. Also move the Hyper-V reference TSC initialization much earlier in the boot process so no discontinuity is observed when pv_ops.time.sched_clock calculates its offset. [ tglx: Folded build fix ] Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lkml.kernel.org/r/20190814123216.32245-3-Tianyu.Lan@microsoft.com
2019-07-08Merge branch 'x86-apic-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x96 apic updates from Thomas Gleixner: "Updates for the x86 APIC interrupt handling and APIC timer: - Fix a long standing issue with spurious interrupts which was caused by the big vector management rework a few years ago. Robert Hodaszi provided finally enough debug data and an excellent initial failure analysis which allowed to understand the underlying issues. This contains a change to the core interrupt management code which is required to handle this correctly for the APIC/IO_APIC. The core changes are NOOPs for most architectures except ARM64. ARM64 is not impacted by the change as confirmed by Marc Zyngier. - Newer systems allow to disable the PIT clock for power saving causing panic in the timer interrupt delivery check of the IO/APIC when the HPET timer is not enabled either. While the clock could be turned on this would cause an endless whack a mole game to chase the proper register in each affected chipset. These systems provide the relevant frequencies for TSC, CPU and the local APIC timer via CPUID and/or MSRs, which allows to avoid the PIT/HPET based calibration. As the calibration code is the only usage of the legacy timers on modern systems and is skipped anyway when the frequencies are known already, there is no point in setting up the PIT and actually checking for the interrupt delivery via IO/APIC. To achieve this on a wide variety of platforms, the CPUID/MSR based frequency readout has been made more robust, which also allowed to remove quite some workarounds which turned out to be not longer required. Thanks to Daniel Drake for analysis, patches and verification" * 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/irq: Seperate unused system vectors from spurious entry again x86/irq: Handle spurious interrupt after shutdown gracefully x86/ioapic: Implement irq_get_irqchip_state() callback genirq: Add optional hardware synchronization for shutdown genirq: Fix misleading synchronize_irq() documentation genirq: Delay deactivation in free_irq() x86/timer: Skip PIT initialization on modern chipsets x86/apic: Use non-atomic operations when possible x86/apic: Make apic_bsp_setup() static x86/tsc: Set LAPIC timer period to crystal clock frequency x86/apic: Rename 'lapic_timer_frequency' to 'lapic_timer_period' x86/tsc: Use CPUID.0x16 to calculate missing crystal frequency
2019-07-03clocksource/drivers: Make Hyper-V clocksource ISA agnosticMichael Kelley
Hyper-V clock/timer code and data structures are currently mixed in with other code in the ISA independent drivers/hv directory as well as the ISA dependent Hyper-V code under arch/x86. Consolidate this code and data structures into a Hyper-V clocksource driver to better follow the Linux model. In doing so, separate out the ISA dependent portions so the new clocksource driver works for x86 and for the in-process Hyper-V on ARM64 code. To start, move the existing clockevents code to create the new clocksource driver. Update the VMbus driver to call initialization and cleanup routines since the Hyper-V synthetic timers are not independently enumerated in ACPI. No behavior is changed and no new functionality is added. Suggested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: "bp@alien8.de" <bp@alien8.de> Cc: "will.deacon@arm.com" <will.deacon@arm.com> Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com> Cc: "mark.rutland@arm.com" <mark.rutland@arm.com> Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org> Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org> Cc: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org> Cc: "olaf@aepfle.de" <olaf@aepfle.de> Cc: "apw@canonical.com" <apw@canonical.com> Cc: "jasowang@redhat.com" <jasowang@redhat.com> Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com> Cc: Sunil Muthuswamy <sunilmut@microsoft.com> Cc: KY Srinivasan <kys@microsoft.com> Cc: "sashal@kernel.org" <sashal@kernel.org> Cc: "vincenzo.frascino@arm.com" <vincenzo.frascino@arm.com> Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org> Cc: "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org> Cc: "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org> Cc: "arnd@arndb.de" <arnd@arndb.de> Cc: "linux@armlinux.org.uk" <linux@armlinux.org.uk> Cc: "ralf@linux-mips.org" <ralf@linux-mips.org> Cc: "paul.burton@mips.com" <paul.burton@mips.com> Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org> Cc: "salyzyn@android.com" <salyzyn@android.com> Cc: "pcc@google.com" <pcc@google.com> Cc: "shuah@kernel.org" <shuah@kernel.org> Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com> Cc: "linux@rasmusvillemoes.dk" <linux@rasmusvillemoes.dk> Cc: "huw@codeweavers.com" <huw@codeweavers.com> Cc: "sfr@canb.auug.org.au" <sfr@canb.auug.org.au> Cc: "pbonzini@redhat.com" <pbonzini@redhat.com> Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com> Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org> Link: https://lkml.kernel.org/r/1561955054-1838-2-git-send-email-mikelley@microsoft.com
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-09x86/apic: Rename 'lapic_timer_frequency' to 'lapic_timer_period'Daniel Drake
This variable is a period unit (number of clock cycles per jiffy), not a frequency (which is number of cycles per second). Give it a more appropriate name. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Daniel Drake <drake@endlessm.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: len.brown@intel.com Cc: linux@endlessm.com Cc: rafael.j.wysocki@intel.com Link: http://lkml.kernel.org/r/20190509055417.13152-2-drake@endlessm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-28x86/Hyper-V: Set x2apic destination mode to physical when x2apic is availableLan Tianyu
Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, set x2apic destination mode to physcial mode when x2apic is available and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs have 8-bit APIC id. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2018-11-04x86/hyper-v: Enable PIT shutdown quirkMichael Kelley
Hyper-V emulation of the PIT has a quirk such that the normal PIT shutdown path doesn't work, because clearing the counter register restarts the timer. Disable the counter clearing on PIT shutdown. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org> Cc: "devel@linuxdriverproject.org" <devel@linuxdriverproject.org> Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org> Cc: "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org> Cc: "jgross@suse.com" <jgross@suse.com> Cc: "akataria@vmware.com" <akataria@vmware.com> Cc: "olaf@aepfle.de" <olaf@aepfle.de> Cc: "apw@canonical.com" <apw@canonical.com> Cc: vkuznets <vkuznets@redhat.com> Cc: "jasowang@redhat.com" <jasowang@redhat.com> Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com> Cc: KY Srinivasan <kys@microsoft.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1541303219-11142-3-git-send-email-mikelley@microsoft.com
2018-10-09x86/hyperv: Enable PV qspinlock for Hyper-VYi Sun
Implement the required wait and kick callbacks to support PV spinlocks in Hyper-V guests. [ tglx: Document the requirement for disabling interrupts in the wait() callback. Remove goto and unnecessary includes. Add prototype for hv_vcpu_is_preempted(). Adapted to pending paravirt changes. ] Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> Cc: chao.p.peng@intel.com Cc: chao.gao@intel.com Cc: isaku.yamahata@intel.com Cc: tianyu.lan@microsoft.com Link: https://lkml.kernel.org/r/1538987374-51217-3-git-send-email-yi.y.sun@linux.intel.com
2018-07-03Drivers: hv: vmbus: Make TLFS #define names architecture neutralMichael Kelley
The Hyper-V feature and hint flags in hyperv-tlfs.h are all defined with the string "X64" in the name. Some of these flags are indeed x86/x64 specific, but others are not. For the ones that are used in architecture independent Hyper-V driver code, or will be used in the upcoming support for Hyper-V for ARM64, this patch removes the "X64" from the name. This patch changes the flags that are currently known to be used on multiple architectures. Hyper-V for ARM64 is still a work-in-progress and the Top Level Functional Spec (TLFS) has not been separated into x86/x64 and ARM64 areas. So additional flags may need to be updated later. This patch only changes symbol names. There are no functional changes. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-03x86/hyperv: Add interrupt handler annotationsMichael Kelley
Add standard interrupt handler annotations to hyperv_vector_handler(). This does not fix any observed bug, but avoids potential removal of the code by link time optimization and makes it consistent with hv_stimer0_vector_handler in the same source file. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-09Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "ARM: - VHE optimizations - EL2 address space randomization - speculative execution mitigations ("variant 3a", aka execution past invalid privilege register access) - bugfixes and cleanups PPC: - improvements for the radix page fault handler for HV KVM on POWER9 s390: - more kvm stat counters - virtio gpu plumbing - documentation - facilities improvements x86: - support for VMware magic I/O port and pseudo-PMCs - AMD pause loop exiting - support for AMD core performance extensions - support for synchronous register access - expose nVMX capabilities to userspace - support for Hyper-V signaling via eventfd - use Enlightened VMCS when running on Hyper-V - allow userspace to disable MWAIT/HLT/PAUSE vmexits - usual roundup of optimizations and nested virtualization bugfixes Generic: - API selftest infrastructure (though the only tests are for x86 as of now)" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (174 commits) kvm: x86: fix a prototype warning kvm: selftests: add sync_regs_test kvm: selftests: add API testing infrastructure kvm: x86: fix a compile warning KVM: X86: Add Force Emulation Prefix for "emulate the next instruction" KVM: X86: Introduce handle_ud() KVM: vmx: unify adjacent #ifdefs x86: kvm: hide the unused 'cpu' variable KVM: VMX: remove bogus WARN_ON in handle_ept_misconfig Revert "KVM: X86: Fix SMRAM accessing even if VM is shutdown" kvm: Add emulation for movups/movupd KVM: VMX: raise internal error for exception during invalid protected mode state KVM: nVMX: Optimization: Dont set KVM_REQ_EVENT when VMExit with nested_run_pending KVM: nVMX: Require immediate-exit when event reinjected to L2 and L1 event pending KVM: x86: Fix misleading comments on handling pending exceptions KVM: x86: Rename interrupt.pending to interrupt.injected KVM: VMX: No need to clear pending NMI/interrupt on inject realmode interrupt x86/kvm: use Enlightened VMCS when running on Hyper-V x86/hyper-v: detect nested features x86/hyper-v: define struct hv_enlightened_vmcs and clean field bits ...
2018-03-28x86/hyper-v: detect nested featuresVitaly Kuznetsov
TLFS 5.0 says: "Support for an enlightened VMCS interface is reported with CPUID leaf 0x40000004. If an enlightened VMCS interface is supported, additional nested enlightenments may be discovered by reading the CPUID leaf 0x4000000A (see 2.4.11)." Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-03-28x86/hyper-v: move definitions from TLFS to hyperv-tlfs.hVitaly Kuznetsov
mshyperv.h now only contains fucntions/variables we define in kernel, all definitions from TLFS should go to hyperv-tlfs.h. 'enum hv_cpuid_function' is removed as we already have this info in hyperv-tlfs.h, code in mshyperv.c is adjusted accordingly. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-03-28x86/hyper-v: move hyperv.h out of uapiVitaly Kuznetsov
hyperv.h is not part of uapi, there are no (known) users outside of kernel. We are making changes to this file to match current Hyper-V Hypervisor Top-Level Functional Specification (TLFS, see: https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs) and we don't want to maintain backwards compatibility. Move the file renaming to hyperv-tlfs.h to avoid confusing it with mshyperv.h. In future, all definitions from TLFS should go to it and all kernel objects should go to mshyperv.h or include/linux/hyperv.h. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2018-03-06Drivers: hv: vmbus: Implement Direct Mode for stimer0Michael Kelley
The 2016 version of Hyper-V offers the option to operate the guest VM per-vcpu stimer's in Direct Mode, which means the timer interupts on its own vector rather than queueing a VMbus message. Direct Mode reduces timer processing overhead in both the hypervisor and the guest, and avoids having timer interrupts pollute the VMbus interrupt stream for the synthetic NIC and storage. This patch enables Direct Mode by default on stimer0 when running on a version of Hyper-V that supports it. In prep for coming support of Hyper-V on ARM64, the arch independent portion of the code contains calls to routines that will be populated on ARM64 but are not needed and do nothing on x86. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>