Changes in hyp_trace.c

01f492e1817e858d1712f2489d0afbaa552f417b - Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Fri, 17 Apr 2026 16:18:03 +0200

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmPull kvm updates from Paolo Bonzini: "Arm: - Add support for tracing in the standalone EL2 hypervisor code, which should help both debugging and performance analysis. This uses the new infrastructure for 'remote' trace buffers that can be exposed by non-kernel entities such as firmware, and which came through the tracing tree - Add support for GICv5 Per Processor Interrupts (PPIs), as the starting point for supporting the new GIC architecture in KVM - Finally add support for pKVM protected guests, where pages are unmapped from the host as they are faulted into the guest and can be shared back from the guest using pKVM hypercalls. Protected guests are created using a new machine type identifier. As the elusive guestmem has not yet delivered on its promises, anonymous memory is also supported This is only a first step towards full isolation from the host; for example, the CPU register state and DMA accesses are not yet isolated. Because this does not really yet bring fully what it promises, it is hidden behind CONFIG_ARM_PKVM_GUEST + 'kvm-arm.mode=protected', and also triggers TAINT_USER when a VM is created. Caveat emptor - Rework the dreaded user_mem_abort() function to make it more maintainable, reducing the amount of state being exposed to the various helpers and rendering a substantial amount of state immutable - Expand the Stage-2 page table dumper to support NV shadow page tables on a per-VM basis - Tidy up the pKVM PSCI proxy code to be slightly less hard to follow - Fix both SPE and TRBE in non-VHE configurations so that they do not generate spurious, out of context table walks that ultimately lead to very bad HW lockups - A small set of patches fixing the Stage-2 MMU freeing in error cases - Tighten-up accepted SMC immediate value to be only #0 for host SMCCC calls - The usual cleanups and other selftest churn LoongArch: - Use CSR_CRMD_PLV for kvm_arch_vcpu_in_kernel() - Add DMSINTC irqchip in kernel support RISC-V: - Fix steal time shared memory alignment checks - Fix vector context allocation leak - Fix array out-of-bounds in pmu_ctr_read() and pmu_fw_ctr_read_hi() - Fix double-free of sdata in kvm_pmu_clear_snapshot_area() - Fix integer overflow in kvm_pmu_validate_counter_mask() - Fix shift-out-of-bounds in make_xfence_request() - Fix lost write protection on huge pages during dirty logging - Split huge pages during fault handling for dirty logging - Skip CSR restore if VCPU is reloaded on the same core - Implement kvm_arch_has_default_irqchip() for KVM selftests - Factored-out ISA checks into separate sources - Added hideleg to struct kvm_vcpu_config - Factored-out VCPU config into separate sources - Support configuration of per-VM HGATP mode from KVM user space s390: - Support for ESA (31-bit) guests inside nested hypervisors - Remove restriction on memslot alignment, which is not needed anymore with the new gmap code - Fix LPSW/E to update the bear (which of course is the breaking event address register) x86: - Shut up various UBSAN warnings on reading module parameter before they were initialized - Don't zero-allocate page tables that are used for splitting hugepages in the TDP MMU, as KVM is guaranteed to set all SPTEs in the page table and thus write all bytes - As an optimization, bail early when trying to unsync 4KiB mappings if the target gfn can just be mapped with a 2MiB hugepage x86 generic: - Copy single-chunk MMIO write values into struct kvm_vcpu (more precisely struct kvm_mmio_fragment) to fix use-after-free stack bugs where KVM would dereference stack pointer after an exit to userspace - Clean up and comment the emulated MMIO code to try to make it easier to maintain (not necessarily "easy", but "easier") - Move VMXON+VMXOFF and EFER.SVME toggling out of KVM (not *all* of VMX and SVM enabling) as it is needed for trusted I/O - Advertise support for AVX512 Bit Matrix Multiply (BMM) instructions - Immediately fail the build if a required #define is missing in one of KVM's headers that is included multiple times - Reject SET_GUEST_DEBUG with -EBUSY if there's an already injected exception, mostly to prevent syzkaller from abusing the uAPI to trigger WARNs, but also because it can help prevent userspace from unintentionally crashing the VM - Exempt SMM from CPUID faulting on Intel, as per the spec - Misc hardening and cleanup changes x86 (AMD): - Fix and optimize IRQ window inhibit handling for AVIC; make it per-vCPU so that KVM doesn't prematurely re-enable AVIC if multiple vCPUs have to-be-injected IRQs - Clean up and optimize the OSVW handling, avoiding a bug in which KVM would overwrite state when enabling virtualization on multiple CPUs in parallel. This should not be a problem because OSVW should usually be the same for all CPUs - Drop a WARN in KVM_MEMORY_ENCRYPT_REG_REGION where KVM complains about a "too large" size based purely on user input - Clean up and harden the pinning code for KVM_MEMORY_ENCRYPT_REG_REGION - Disallow synchronizing a VMSA of an already-launched/encrypted vCPU, as doing so for an SNP guest will crash the host due to an RMP violation page fault - Overhaul KVM's APIs for detecting SEV+ guests so that VM-scoped queries are required to hold kvm->lock, and enforce it by lockdep. Fix various bugs where sev_guest() was not ensured to be stable for the whole duration of a function or ioctl - Convert a pile of kvm->lock SEV code to guard() - Play nicer with userspace that does not enable KVM_CAP_EXCEPTION_PAYLOAD, for which KVM needs to set CR2 and DR6 as a response to ioctls such as KVM_GET_VCPU_EVENTS (even if the payload would end up in EXITINFO2 rather than CR2, for example). Only set CR2 and DR6 when consumption of the payload is imminent, but on the other hand force delivery of the payload in all paths where userspace retrieves CR2 or DR6 - Use vcpu->arch.cr2 when updating vmcb12's CR2 on nested #VMEXIT instead of vmcb02->save.cr2. The value is out of sync after a save/restore or after a #PF is injected into L2 - Fix a class of nSVM bugs where some fields written by the CPU are not synchronized from vmcb02 to cached vmcb12 after VMRUN, and so are not up-to-date when saved by KVM_GET_NESTED_STATE - Fix a class of bugs where the ordering between KVM_SET_NESTED_STATE and KVM_SET_{S}REGS could cause vmcb02 to be incorrectly initialized after save+restore - Add a variety of missing nSVM consistency checks - Fix several bugs where KVM failed to correctly update VMCB fields on nested #VMEXIT - Fix several bugs where KVM failed to correctly synthesize #UD or #GP for SVM-related instructions - Add support for save+restore of virtualized LBRs (on SVM) - Refactor various helpers and macros to improve clarity and (hopefully) make the code easier to maintain - Aggressively sanitize fields when copying from vmcb12, to guard against unintentionally allowing L1 to utilize yet-to-be-defined features - Fix several bugs where KVM botched rAX legality checks when emulating SVM instructions. There are remaining issues in that KVM doesn't handle size prefix overrides for 64-bit guests - Fail emulation of VMRUN/VMLOAD/VMSAVE if mapping vmcb12 fails instead of somewhat arbitrarily synthesizing #GP (i.e. don't double down on AMD's architectural but sketchy behavior of generating #GP for "unsupported" addresses) - Cache all used vmcb12 fields to further harden against TOCTOU bugs x86 (Intel): - Drop obsolete branch hint prefixes from the VMX instruction macros - Use ASM_INPUT_RM() in __vmcs_writel() to coerce clang into using a register input when appropriate - Code cleanups guest_memfd: - Don't mark guest_memfd folios as accessed, as guest_memfd doesn't support reclaim, the memory is unevictable, and there is no storage to write back to LoongArch selftests: - Add KVM PMU test cases s390 selftests: - Enable more memory selftests x86 selftests: - Add support for Hygon CPUs in KVM selftests - Fix a bug in the MSR test where it would get false failures on AMD/Hygon CPUs with exactly one of RDPID or RDTSCP - Add an MADV_COLLAPSE testcase for guest_memfd as a regression test for a bug where the kernel would attempt to collapse guest_memfd folios against KVM's will"* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (373 commits) KVM: x86: use inlines instead of macros for is_sev_*guest x86/virt: Treat SVM as unsupported when running as an SEV+ guest KVM: SEV: Goto an existing error label if charging misc_cg for an ASID fails KVM: SVM: Move lock-protected allocation of SEV ASID into a separate helper KVM: SEV: use mutex guard in snp_handle_guest_req() KVM: SEV: use mutex guard in sev_mem_enc_unregister_region() KVM: SEV: use mutex guard in sev_mem_enc_ioctl() KVM: SEV: use mutex guard in snp_launch_update() KVM: SEV: Assert that kvm->lock is held when querying SEV+ support KVM: SEV: Document that checking for SEV+ guests when reclaiming memory is "safe" KVM: SEV: Hide "struct kvm_sev_info" behind CONFIG_KVM_AMD_SEV=y KVM: SEV: WARN on unhandled VM type when initializing VM KVM: LoongArch: selftests: Add PMU overflow interrupt test KVM: LoongArch: selftests: Add basic PMU event counting test KVM: LoongArch: selftests: Add cpucfg read/write helpers LoongArch: KVM: Add DMSINTC inject msi to vCPU LoongArch: KVM: Add DMSINTC device support LoongArch: KVM: Make vcpu_is_preempted() as a macro rather than function LoongArch: KVM: Move host CSR_GSTAT save and restore in context switch LoongArch: KVM: Move host CSR_EENTRY save and restore in context switch ... List of files: /linux/arch/arm64/kvm/hyp_trace.c

e74c3a8891c05f88eeb87121de7e12dc95766a4a - Merge tag 'kvmarm-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

Mon, 13 Apr 2026 11:49:54 +0200

Merge tag 'kvmarm-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEADKVM/arm64 updates for 7.1* New features:- Add support for tracing in the standalone EL2 hypervisor code, which should help both debugging and performance analysis. This comes with a full infrastructure for 'remote' trace buffers that can be exposed by non-kernel entities such as firmware.- Add support for GICv5 Per Processor Interrupts (PPIs), as the starting point for supporting the new GIC architecture in KVM.- Finally add support for pKVM protected guests, with anonymous memory being used as a backing store. About time!* Improvements and bug fixes:- Rework the dreaded user_mem_abort() function to make it more maintainable, reducing the amount of state being exposed to the various helpers and rendering a substantial amount of state immutable.- Expand the Stage-2 page table dumper to support NV shadow page tables on a per-VM basis.- Tidy up the pKVM PSCI proxy code to be slightly less hard to follow.- Fix both SPE and TRBE in non-VHE configurations so that they do not generate spurious, out of context table walks that ultimately lead to very bad HW lockups.- A small set of patches fixing the Stage-2 MMU freeing in error cases.- Tighten-up accepted SMC immediate value to be only #0 for host SMCCC calls.- The usual cleanups and other selftest churn. List of files: /linux/arch/arm64/kvm/hyp_trace.c

2de32a25a3f721052c9aaf753a65b96f63c2c7d9 - Merge branch kvm-arm64/hyp-tracing into kvmarm-master/next

Wed, 08 Apr 2026 13:21:51 +0200

Merge branch kvm-arm64/hyp-tracing into kvmarm-master/next* kvm-arm64/hyp-tracing: (40 commits) : . : EL2 tracing support, adding both 'remote' ring-buffer : infrastructure and the tracing itself, courtesy of : Vincent Donnefort. From the cover letter: : : "The growing set of features supported by the hypervisor in protected : mode necessitates debugging and profiling tools. Tracefs is the : ideal candidate for this task: : : * It is simple to use and to script. : : * It is supported by various tools, from the trace-cmd CLI to the : Android web-based perfetto. : : * The ring-buffer, where are stored trace events consists of linked : pages, making it an ideal structure for sharing between kernel and : hypervisor. : : This series first introduces a new generic way of creating remote events and : remote buffers. Then it adds support to the pKVM hypervisor." : . tracing: selftests: Extend hotplug testing for trace remotes tracing: Non-consuming read for trace remotes with an offline CPU tracing: Adjust cmd_check_undefined to show unexpected undefined symbols tracing: Restore accidentally removed SPDX tag KVM: arm64: avoid unused-variable warning tracing: Generate undef symbols allowlist for simple_ring_buffer KVM: arm64: tracing: add ftrace dependency tracing: add more symbols to whitelist tracing: Update undefined symbols allow list for simple_ring_buffer KVM: arm64: Fix out-of-tree build for nVHE/pKVM tracing tracing: selftests: Add hypervisor trace remote tests KVM: arm64: Add selftest event support to nVHE/pKVM hyp KVM: arm64: Add hyp_enter/hyp_exit events to nVHE/pKVM hyp KVM: arm64: Add event support to the nVHE/pKVM hyp and trace remote KVM: arm64: Add trace reset to the nVHE/pKVM hyp KVM: arm64: Sync boot clock with the nVHE/pKVM hyp KVM: arm64: Add trace remote for the nVHE/pKVM hyp KVM: arm64: Add tracing capability for the nVHE/pKVM hyp KVM: arm64: Support unaligned fixmap in the pKVM hyp KVM: arm64: Initialise hyp_nr_cpus for nVHE hyp ...Signed-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

8510d054b7e086a71a9191ac3399231290dfd272 - KVM: arm64: avoid unused-variable warning

Fri, 13 Mar 2026 10:49:16 +0100

KVM: arm64: avoid unused-variable warningThe 'cpu' variable is only used inside of an #ifdef block and causesa warning if there is no user:arch/arm64/kvm/hyp_trace.c: In function 'kvm_hyp_trace_init':arch/arm64/kvm/hyp_trace.c:422:13: error: unused variable 'cpu' [-Werror=unused-variable] 422 | int cpu; | ^~~Change the #ifdef to an equivalent IS_ENABLED() check to avoidthe warning.Fixes: b22888917fa4 ("KVM: arm64: Sync boot clock with the nVHE/pKVM hyp")Signed-off-by: Arnd Bergmann Reviewed-by: Vincent Donnefort Link: https://patch.msgid.link/20260313094925.3749287-1-arnd@kernel.orgSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

5bbbed42f71f771a70e974e3726d283690ecd589 - KVM: arm64: Add selftest event support to nVHE/pKVM hyp

Mon, 09 Mar 2026 17:25:15 +0100

KVM: arm64: Add selftest event support to nVHE/pKVM hypAdd a selftest event that can be triggered from a `write_event` tracefsfile. This intends to be used by trace remote selftests.Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-30-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

696dfec22b8e4ac57cc90558af2b6be2b37f4b95 - KVM: arm64: Add hyp_enter/hyp_exit events to nVHE/pKVM hyp

Mon, 09 Mar 2026 17:25:14 +0100

KVM: arm64: Add hyp_enter/hyp_exit events to nVHE/pKVM hypThe hyp_enter and hyp_exit events are logged by the hypervisor any timeit is entered and exited.Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-29-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

0a90fbc8a1709f682e0196c2632027cdedae5e94 - KVM: arm64: Add event support to the nVHE/pKVM hyp and trace remote

Mon, 09 Mar 2026 17:25:13 +0100

KVM: arm64: Add event support to the nVHE/pKVM hyp and trace remoteAllow the creation of hypervisor and trace remote events with a singlemacro HYP_EVENT(). That macro expands in the kernel side to add allthe required declarations (based on REMOTE_EVENT()) as well as in thehypervisor side to create the trace_() function.Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-28-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

2194d317e07d169efc113344c531621ce31afe64 - KVM: arm64: Add trace reset to the nVHE/pKVM hyp

Mon, 09 Mar 2026 17:25:12 +0100

KVM: arm64: Add trace reset to the nVHE/pKVM hypMake the hypervisor reset either the whole tracing buffer or a specificring-buffer, on remotes/hypervisor/trace or per_cpu//trace writeaccess.Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-27-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

b22888917fa411d100339ef9d418b4eb86aba962 - KVM: arm64: Sync boot clock with the nVHE/pKVM hyp

Mon, 09 Mar 2026 17:25:11 +0100

KVM: arm64: Sync boot clock with the nVHE/pKVM hypConfigure the hypervisor tracing clock with the kernel boot clock. Fortracing purposes, the boot clock is interesting: it doesn't stop onsuspend. However, it is corrected on a regular basis, which implies theneed to re-evaluate it every once in a while.Cc: John Stultz Cc: Thomas Gleixner Cc: Stephen Boyd Cc: Christopher S. Hall Cc: Richard Cochran Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-26-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c

3aed038aac8d897016a2b6e1935f16c7640918d4 - KVM: arm64: Add trace remote for the nVHE/pKVM hyp

Mon, 09 Mar 2026 17:25:10 +0100

KVM: arm64: Add trace remote for the nVHE/pKVM hypIn both protected and nVHE mode, the hypervisor is capable of writingevents into tracefs compatible ring-buffers. Create a trace remote sothe kernel can read those buffers.This currently doesn't provide any event support which will come later.Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260309162516.2623589-25-vdonnefort@google.comSigned-off-by: Marc Zyngier List of files: /linux/arch/arm64/kvm/hyp_trace.c