lwn.git/include/linux, branch docs-5.19

Merge tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2022-04-03T19:26:01+00:00

Pull more tracing updates from Steven Rostedt: - Rename the staging files to give them some meaning. Just stage1,stag2,etc, does not show what they are for - Check for NULL from allocation in bootconfig - Hold event mutex for dyn_event call in user events - Mark user events to broken (to work on the API) - Remove eBPF updates from user events - Remove user events from uapi header to keep it from being installed. - Move ftrace_graph_is_dead() into inline as it is called from hot paths and also convert it into a static branch. * tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Move user_events.h temporarily out of include/uapi ftrace: Make ftrace_graph_is_dead() a static branch tracing: Set user_events to BROKEN tracing/user_events: Remove eBPF interfaces tracing/user_events: Hold event_mutex during dyn_event_add proc: bootconfig: Add null pointer check tracing: Rename the staging files for trace_events

Merge tag 'core-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-04-03T19:08:26+00:00

Pull RT signal fix from Thomas Gleixner: "Revert the RT related signal changes. They need to be reworked and generalized" * tag 'core-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"

Merge tag 'dma-mapping-5.18-1' of git://git.infradead.org/users/hch/dma-mapping

2022-04-03T17:31:00+00:00

Pull more dma-mapping updates from Christoph Hellwig: - fix a regression in dma remap handling vs AMD memory encryption (me) - finally kill off the legacy PCI DMA API (Christophe JAILLET) * tag 'dma-mapping-5.18-1' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: move pgprot_decrypted out of dma_pgprot PCI/doc: cleanup references to the legacy PCI DMA API PCI: Remove the deprecated "pci-dma-compat.h" API

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2022-04-02T19:09:02+00:00

Pull kvm fixes from Paolo Bonzini: - Only do MSR filtering for MSRs accessed by rdmsr/wrmsr - Documentation improvements - Prevent module exit until all VMs are freed - PMU Virtualization fixes - Fix for kvm_irq_delivery_to_apic_fast() NULL-pointer dereferences - Other miscellaneous bugfixes * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits) KVM: x86: fix sending PV IPI KVM: x86/mmu: do compare-and-exchange of gPTE via the user address KVM: x86: Remove redundant vm_entry_controls_clearbit() call KVM: x86: cleanup enter_rmode() KVM: x86: SVM: fix tsc scaling when the host doesn't support it kvm: x86: SVM: remove unused defines KVM: x86: SVM: move tsc ratio definitions to svm.h KVM: x86: SVM: fix avic spec based definitions again KVM: MIPS: remove reference to trap&emulate virtualization KVM: x86: document limitations of MSR filtering KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr KVM: x86/emulator: Emulate RDPID only if it is enabled in guest KVM: x86/pmu: Fix and isolate TSX-specific performance event logic KVM: x86: mmu: trace kvm_mmu_set_spte after the new SPTE was set KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRs KVM: x86: Trace all APICv inhibit changes and capture overall status KVM: x86: Add wrappers for setting/clearing APICv inhibits KVM: x86: Make APICv inhibit reasons an enum and cleanup naming KVM: X86: Handle implicit supervisor access with SMAP KVM: X86: Rename variable smap to not_smap in permission_fault() ...

tracing: mark user_events as BROKEN

2022-04-02T17:32:14+00:00

After being merged, user_events become more visible to a wider audience that have concerns with the current API. It is too late to fix this for this release, but instead of a full revert, just mark it as BROKEN (which prevents it from being selected in make config). Then we can work finding a better API. If that fails, then it will need to be completely reverted. To not have the code silently bitrot, still allow building it with COMPILE_TEST. And to prevent the uapi header from being installed, then later changed, and then have an old distro user space see the old version, move the header file out of the uapi directory. Surround the include with CONFIG_COMPILE_TEST to the current location, but when the BROKEN tag is taken off, it will use the uapi directory, and fail to compile. This is a good way to remind us to move the header back. Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.com Suggested-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) Signed-off-by: Linus Torvalds

tracing: Move user_events.h temporarily out of include/uapi

2022-04-02T12:40:10+00:00

While user_events API is under development and has been marked for broken to not let the API become fixed, move the header file out of the uapi directory. This is to prevent it from being installed, then later changed, and then have an old distro user space update with a new kernel, where applications see the user_events being available, but the old header is in place, and then they get compiled incorrectly. Also, surround the include with CONFIG_COMPILE_TEST to the current location, but when the BROKEN tag is taken off, it will use the uapi directory, and fail to compile. This is a good way to remind us to move the header back. Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.com Link: https://lkml.kernel.org/r/20220401143903.188384f3@gandalf.local.home Suggested-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google)

ftrace: Make ftrace_graph_is_dead() a static branch

2022-04-02T12:40:09+00:00

ftrace_graph_is_dead() is used on hot paths, it just reads a variable in memory and is not worth suffering function call constraints. For instance, at entry of prepare_ftrace_return(), inlining it avoids saving prepare_ftrace_return() parameters to stack and restoring them after calling ftrace_graph_is_dead(). While at it using a static branch is even more performant and is rather well adapted considering that the returned value will almost never change. Inline ftrace_graph_is_dead() and replace 'kill_ftrace_graph' bool by a static branch. The performance improvement is noticeable. Link: https://lkml.kernel.org/r/e0411a6a0ed3eafff0ad2bc9cd4b0e202b4617df.1648623570.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Signed-off-by: Steven Rostedt (Google)

KVM: Remove dirty handling from gfn_to_pfn_cache completely

2022-04-02T09:34:41+00:00

It isn't OK to cache the dirty status of a page in internal structures for an indefinite period of time. Any time a vCPU exits the run loop to userspace might be its last; the VMM might do its final check of the dirty log, flush the last remaining dirty pages to the destination and complete a live migration. If we have internal 'dirty' state which doesn't get flushed until the vCPU is finally destroyed on the source after migration is complete, then we have lost data because that will escape the final copy. This problem already exists with the use of kvm_vcpu_unmap() to mark pages dirty in e.g. VMX nesting. Note that the actual Linux MM already considers the page to be dirty since we have a writeable mapping of it. This is just about the KVM dirty logging. For the nesting-style use cases (KVM_GUEST_USES_PFN) we will need to track which gfn_to_pfn_caches have been used and explicitly mark the corresponding pages dirty before returning to userspace. But we would have needed external tracking of that anyway, rather than walking the full list of GPCs to find those belonging to this vCPU which are dirty. So let's rely *solely* on that external tracking, and keep it simple rather than laying a tempting trap for callers to fall into. Signed-off-by: David Woodhouse Signed-off-by: Paolo Bonzini Message-Id: <20220303154127.202856-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini

KVM: Use enum to track if cached PFN will be used in guest and/or host

2022-04-02T09:34:41+00:00

Replace the guest_uses_pa and kernel_map booleans in the PFN cache code with a unified enum/bitmask. Using explicit names makes it easier to review and audit call sites. Opportunistically add a WARN to prevent passing garbage; instantating a cache without declaring its usage is either buggy or pointless. Signed-off-by: Sean Christopherson Signed-off-by: David Woodhouse Signed-off-by: Paolo Bonzini Message-Id: <20220303154127.202856-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini

KVM: Don't actually set a request when evicting vCPUs for GFN cache invd

2022-04-02T09:34:39+00:00

Don't actually set a request bit in vcpu->requests when making a request purely to force a vCPU to exit the guest. Logging a request but not actually consuming it would cause the vCPU to get stuck in an infinite loop during KVM_RUN because KVM would see the pending request and bail from VM-Enter to service the request. Note, it's currently impossible for KVM to set KVM_REQ_GPC_INVALIDATE as nothing in KVM is wired up to set guest_uses_pa=true. But, it'd be all too easy for arch code to introduce use of kvm_gfn_to_pfn_cache_init() without implementing handling of the request, especially since getting test coverage of MMU notifier interaction with specific KVM features usually requires a directed test. Opportunistically rename gfn_to_pfn_cache_invalidate_start()'s wake_vcpus to evict_vcpus. The purpose of the request is to get vCPUs out of guest mode, it's supposed to _avoid_ waking vCPUs that are blocking. Opportunistically rename KVM_REQ_GPC_INVALIDATE to be more specific as to what it wants to accomplish, and to genericize the name so that it can used for similar but unrelated scenarios, should they arise in the future. Add a comment and documentation to explain why the "no action" request exists. Add compile-time assertions to help detect improper usage. Use the inner assertless helper in the one s390 path that makes requests without a hardcoded request. Cc: David Woodhouse Signed-off-by: Sean Christopherson Message-Id: <20220223165302.3205276-1-seanjc@google.com> Signed-off-by: Paolo Bonzini