kernel/linux.git/arch/x86/events, branch linux-7.1.y

perf/x86/intel: Enable auto counter reload for DMR

2026-05-05T10:47:22+00:00

Panther cove µarch starts to support auto counter reload (ACR), but the static_call intel_pmu_enable_acr_event() is not updated for the Panther Cove µarch used by DMR. It leads to the auto counter reload is not really enabled on DMR. Update static_call intel_pmu_enable_acr_event() in intel_pmu_init_pnc(). Fixes: d345b6bb8860 ("perf/x86/intel: Add core PMU support for DMR") Signed-off-by: Dapeng Mi Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260430002558.712334-5-dapeng1.mi@linux.intel.com

perf/x86/intel: Disable PMI for self-reloaded ACR events

2026-05-05T10:47:21+00:00

On platforms with Auto Counter Reload (ACR) support, such as NVL, a "NMI received for unknown reason 30" warning is observed when running multiple events in a group with ACR enabled: $ perf record -e '{instructions/period=20000,acr_mask=0x2/u,\ cycles/period=40000,acr_mask=0x3/u}' ./test The warning occurs because the Performance Monitoring Interrupt (PMI) is enabled for the self-reloaded event (the cycles event in this case). According to the Intel SDM, the overflow bit (IA32_PERF_GLOBAL_STATUS.PMCn_OVF) is never set for self-reloaded events. Since the bit is not set, the perf NMI handler cannot identify the source of the interrupt, leading to the "unknown reason" message. Furthermore, enabling PMI for self-reloaded events is unnecessary and can lead to extraneous records that pollute the user's requested data. Disable the interrupt bit for all events configured with ACR self-reload. Fixes: ec980e4facef ("perf/x86/intel: Support auto counter reload") Reported-by: Andi Kleen Signed-off-by: Dapeng Mi Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260430002558.712334-4-dapeng1.mi@linux.intel.com

perf/x86/intel: Always reprogram ACR events to prevent stale masks

2026-05-05T10:47:21+00:00

Members of an ACR group are logically linked via a bitmask of their hardware counter indices. If some members of the group are assigned new hardware counters during rescheduling, even events that keep their original counter index must be updated with a new mask. Without this, an event will continue to use a stale acr_mask that references the old indices of its group peers. Ensure all ACR events are reprogrammed during the scheduling path to maintain consistency across the group. Fixes: ec980e4facef ("perf/x86/intel: Support auto counter reload") Signed-off-by: Dapeng Mi Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260430002558.712334-3-dapeng1.mi@linux.intel.com

perf/x86/intel: Improve validation and configuration of ACR masks

2026-05-05T10:47:21+00:00

Currently there are several issues on the user space ACR mask validation and configuration. - The validation for user space ACR mask (attr.config2) is incomplete, e.g., the ACR mask could include the index which belongs to another ACR events group, but it's not validated. - An early return on an invalid ACR mask caused all subsequent ACR groups to be skipped. - The stale hardware ACR mask (hw.config1) is not cleared before setting new hardware ACR mask. The following changes address all of the above issues. - Figure out the event index group of an ACR group. Any bits in the user-space mask not present in the index group are now dropped. - Instead of an early return on invalid bits, drop only the invalid portions and continue iterating through all ACR events to ensure full configuration. - Explicitly clear the stale hardware ACR mask for each event prior to writing the new configuration. Besides, a non-leader event member of ACR group could be disabled in theory. This could cause bit-shifting errors in the acr_mask of remaining group members. But since ACR sampling requires all events to be active, this should not be a big concern in real use case. Add a "FIXME" comment to notice this risk. Fixes: ec980e4facef ("perf/x86/intel: Support auto counter reload") Signed-off-by: Dapeng Mi Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260430002558.712334-2-dapeng1.mi@linux.intel.com

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

2026-04-17T14:18:03+00:00

Pull 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 ...

Merge tag 'x86-cleanups-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T21:03:27+00:00

Pull x86 cleanups from Ingo Molnar: - Consolidate AMD and Hygon cases in parse_topology() (Wei Wang) - asm constraints cleanups in __iowrite32_copy() (Uros Bizjak) - Drop AMD Extended Interrupt LVT macros (Naveen N Rao) - Don't use REALLY_SLOW_IO for delays (Juergen Gross) - paravirt cleanups (Juergen Gross) - FPU code cleanups (Borislav Petkov) - split-lock handling code cleanups (Borislav Petkov, Ronan Pigott) * tag 'x86-cleanups-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Correct the comment explaining what xfeatures_in_use() does x86/split_lock: Don't warn about unknown split_lock_detect parameter x86/fpu: Correct misspelled xfeaures_to_write local var x86/apic: Drop AMD Extended Interrupt LVT macros x86/cpu/topology: Consolidate AMD and Hygon cases in parse_topology() block/floppy: Don't use REALLY_SLOW_IO for delays x86/paravirt: Replace io_delay() hook with a bool x86/irqflags: Preemptively move include paravirt.h directive where it belongs x86/split_lock: Restructure the unwieldy switch-case in sld_state_show() x86/local: Remove trailing semicolon from _ASM_XADD in local_add_return() x86/asm: Use inout "+" asm onstraint modifiers in __iowrite32_copy()

Merge tag 'perf-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T20:22:40+00:00

Pull performance events updates from Ingo Molnar: "Core updates: - Try to allocate task_ctx_data quickly, to optimize O(N^2) algorithm on large systems with O(100k) threads (Namhyung Kim) AMD PMU driver IBS support updates and fixes, by Ravi Bangoria: - Fix interrupt accounting for discarded samples - Fix a Zen5-specific quirk - Fix PhyAddrVal handling - Fix NMI-safety with perf_allow_kernel() - Fix a race between event add and NMIs Intel PMU driver updates: - Only check GP counters for PEBS constraints validation (Dapeng Mi) MSR driver: - Turn SMI_COUNT and PPERF on by default, instead of a long list of CPU models to enable them on (Kan Liang) ... and misc cleanups and fixes by Aldf Conte, Anshuman Khandual, Namhyung Kim, Ravi Bangoria and Yen-Hsiang Hsu" * tag 'perf-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/events: Replace READ_ONCE() with standard pgtable accessors perf/x86/msr: Make SMI and PPERF on by default perf/x86/intel/p4: Fix unused variable warning in p4_pmu_init() perf/x86/intel: Only check GP counters for PEBS constraints validation perf/x86/amd/ibs: Fix comment typo in ibs_op_data perf/amd/ibs: Advertise remote socket capability perf/amd/ibs: Enable streaming store filter perf/amd/ibs: Enable RIP bit63 hardware filtering perf/amd/ibs: Enable fetch latency filtering perf/amd/ibs: Support IBS_{FETCH|OP}_CTL2[Dis] to eliminate RMW race perf/amd/ibs: Add new MSRs and CPUID bits definitions perf/amd/ibs: Define macro for ldlat mask and shift perf/amd/ibs: Avoid race between event add and NMI perf/amd/ibs: Avoid calling perf_allow_kernel() from the IBS NMI handler perf/amd/ibs: Preserve PhyAddrVal bit when clearing PhyAddr MSR perf/amd/ibs: Limit ldlat->l3missonly dependency to Zen5 perf/amd/ibs: Account interrupt for discarded samples perf/core: Simplify __detach_global_ctx_data() perf/core: Try to allocate task_ctx_data quickly perf/core: Pass GFP flags to attach_task_ctx_data()

Merge tag 'kvm-x86-vmxon-7.1' of https://github.com/kvm-x86/linux into HEAD

2026-04-13T11:04:48+00:00

KVM x86 VMXON and EFER.SVME extraction for 7.1 Move _only_ VMXON+VMXOFF and EFER.SVME toggling out of KVM (versus all of VMX and SVM enabling) out of KVM and into the core kernel so that non-KVM TDX enabling, e.g. for trusted I/O, can make SEAMCALLs without needing to ensure KVM is fully loaded. TIO isn't a hypervisor, and isn't trying to be a hypervisor. Specifically, TIO should _never_ have it's own VMCSes (that are visible to the host; the TDX-Module has it's own VMCSes to do SEAMCALL/SEAMRET), and so there is simply no reason to move that functionality out of KVM. With that out of the way, dealing with VMXON/VMXOFF and EFER.SVME is a fairly simple refcounting game.

perf/x86/intel/uncore: Remove extra double quote mark

2026-04-07T07:05:30+00:00

The third argument in INTEL_UNCORE_FR_EVENT_DESC() is subject to __stringify(), and the extra double quote marks can result in the expansion "3.814697266e-6" in the sysfs knobs, instead of 3.814697266e-6. This is incorrect, though it may still work for perf, e.g. perf stat -e uncore_iio_free_running_0/bw_in_port0/ Fixes: d8987048f665 ("perf/x86/intel/uncore: Support IIO free-running counters on DMR") Closes: https://lore.kernel.org/all/20251231224233.113839-1-zide.chen@intel.com/ Reported-by: Chun-Tse Shao Signed-off-by: Zide Chen Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Chun-Tse Shao Reviewed-by: Dapeng Mi Link: https://patch.msgid.link/20260313174050.171704-5-zide.chen@intel.com

perf/x86/intel/uncore: Fix die ID init and look up bugs

2026-04-07T07:05:29+00:00

In snbep_pci2phy_map_init(), in the nr_node_ids > 8 path, uncore_device_to_die() may return -1 when all CPUs associated with the UBOX device are offline. Remove the WARN_ON_ONCE(die_id == -1) check for two reasons: - The current code breaks out of the loop. This is incorrect because pci_get_device() does not guarantee iteration in domain or bus order, so additional UBOX devices may be skipped during the scan. - Returning -EINVAL is incorrect, since marking offline buses with die_id == -1 is expected and should not be treated as an error. Separately, when NUMA is disabled on a NUMA-capable platform, pcibus_to_node() returns NUMA_NO_NODE, causing uncore_device_to_die() to return -1 for all PCI devices. As a result, spr_update_device_location(), used on Intel SPR and EMR, ignores the corresponding PMON units and does not add them to the RB tree. Fix this by using uncore_pcibus_to_dieid(), which retrieves topology from the UBOX GIDNIDMAP register and works regardless of whether NUMA is enabled in Linux. This requires snbep_pci2phy_map_init() to be added in spr_uncore_pci_init(). Keep uncore_device_to_die() only for the nr_node_ids > 8 case, where NUMA is expected to be enabled. Fixes: 9a7832ce3d92 ("perf/x86/intel/uncore: With > 8 nodes, get pci bus die id from NUMA info") Fixes: 65248a9a9ee1 ("perf/x86/uncore: Add a quirk for UPI on SPR") Signed-off-by: Zide Chen Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Dapeng Mi Tested-by: Steve Wahl Link: https://patch.msgid.link/20260313174050.171704-4-zide.chen@intel.com