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2025-03-19x86/cpuid: Refactor <asm/cpuid.h>Ahmed S. Darwish
In preparation for future commits where CPUID headers will be expanded, refactor the CPUID header <asm/cpuid.h> into: asm/cpuid/ ├── api.h └── types.h Move the CPUID data structures into <asm/cpuid/types.h> and the access APIs into <asm/cpuid/api.h>. Let <asm/cpuid.h> be just an include of <asm/cpuid/api.h> so that existing call sites do not break. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250317221824.3738853-2-mingo@kernel.org
2025-03-04x86/cpuid: Include <linux/build_bug.h> in <asm/cpuid.h>Ahmed S. Darwish
<asm/cpuid.h> uses static_assert() at multiple locations but it does not include the CPP macro's definition at linux/build_bug.h. Include the needed header to make <asm/cpuid.h> self-sufficient. This gets triggered when cpuid.h is included in new C files, which is to be done in further commits. Fixes: 43d86e3cd9a7 ("x86/cpu: Provide cpuid_read() et al.") Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250304085152.51092-5-darwi@linutronix.de
2024-12-18x86/cpu: Make all all CPUID leaf names consistentDave Hansen
The leaf names are not consistent. Give them all a CPUID_LEAF_ prefix for consistency and vertical alignment. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Dave Jiang <dave.jiang@intel.com> # for ioatdma bits Link: https://lore.kernel.org/all/20241213205040.7B0C3241%40davehans-spike.ostc.intel.com
2024-12-18x86/fpu: Move CPUID leaf definitions to common codeDave Hansen
Move the XSAVE-related CPUID leaf definitions to common code. Then, use the new definition to remove the last magic number from the CPUID level dependency table. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/all/20241213205037.43C57CDE%40davehans-spike.ostc.intel.com
2024-12-18x86/tsc: Remove CPUID "frequency" leaf magic numbers.Dave Hansen
All the code that reads the CPUID frequency information leaf hard-codes a magic number. Give it a symbolic name and use it. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/all/20241213205036.4397658F%40davehans-spike.ostc.intel.com
2024-12-18x86/cpu: Move TSC CPUID leaf definitionDave Hansen
Prepare to use the TSC CPUID leaf definition more widely by moving it to the common header. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/all/20241213205033.68799E53%40davehans-spike.ostc.intel.com
2024-12-18x86/cpu: Refresh DCA leaf reading codeDave Hansen
The DCA leaf number is also hard-coded in the CPUID level dependency table. Move its definition to common code and use it. While at it, fix up the naming and types in the probe code. All CPUID data is provided in 32-bit registers, not 'unsigned long'. Also stop referring to "level_9". Move away from test_bit() because the type is no longer an 'unsigned long'. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/all/20241213205032.476A30FE%40davehans-spike.ostc.intel.com
2024-12-18x86/cpu: Move MWAIT leaf definition to common headerDave Hansen
Begin constructing a common place to keep all CPUID leaf definitions. Move CPUID_MWAIT_LEAF to the CPUID header and include it where needed. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/all/20241213205028.EE94D02A%40davehans-spike.ostc.intel.com
2024-11-08x86/cpu: Make sure flag_is_changeable_p() is always being usedAndy Shevchenko
When flag_is_changeable_p() is unused, it prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y: arch/x86/kernel/cpu/common.c:351:19: error: unused function 'flag_is_changeable_p' [-Werror,-Wunused-function] 351 | static inline int flag_is_changeable_p(u32 flag) | ^~~~~~~~~~~~~~~~~~~~ Fix this by moving core around to make sure flag_is_changeable_p() is always being used. See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build"). While at it, fix the argument type to be unsigned long along with the local variables, although it currently only runs in 32-bit cases. Besides that, makes it return boolean instead of int. This induces the change of the returning type of have_cpuid_p() to be boolean as well. Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com> Link: https://lore.kernel.org/all/20241108153105.1578186-1-andriy.shevchenko%40linux.intel.com
2024-09-28Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull x86 kvm updates from Paolo Bonzini: "x86: - KVM currently invalidates the entirety of the page tables, not just those for the memslot being touched, when a memslot is moved or deleted. This does not traditionally have particularly noticeable overhead, but Intel's TDX will require the guest to re-accept private pages if they are dropped from the secure EPT, which is a non starter. Actually, the only reason why this is not already being done is a bug which was never fully investigated and caused VM instability with assigned GeForce GPUs, so allow userspace to opt into the new behavior. - Advertise AVX10.1 to userspace (effectively prep work for the "real" AVX10 functionality that is on the horizon) - Rework common MSR handling code to suppress errors on userspace accesses to unsupported-but-advertised MSRs This will allow removing (almost?) all of KVM's exemptions for userspace access to MSRs that shouldn't exist based on the vCPU model (the actual cleanup is non-trivial future work) - Rework KVM's handling of x2APIC ICR, again, because AMD (x2AVIC) splits the 64-bit value into the legacy ICR and ICR2 storage, whereas Intel (APICv) stores the entire 64-bit value at the ICR offset - Fix a bug where KVM would fail to exit to userspace if one was triggered by a fastpath exit handler - Add fastpath handling of HLT VM-Exit to expedite re-entering the guest when there's already a pending wake event at the time of the exit - Fix a WARN caused by RSM entering a nested guest from SMM with invalid guest state, by forcing the vCPU out of guest mode prior to signalling SHUTDOWN (the SHUTDOWN hits the VM altogether, not the nested guest) - Overhaul the "unprotect and retry" logic to more precisely identify cases where retrying is actually helpful, and to harden all retry paths against putting the guest into an infinite retry loop - Add support for yielding, e.g. to honor NEED_RESCHED, when zapping rmaps in the shadow MMU - Refactor pieces of the shadow MMU related to aging SPTEs in prepartion for adding multi generation LRU support in KVM - Don't stuff the RSB after VM-Exit when RETPOLINE=y and AutoIBRS is enabled, i.e. when the CPU has already flushed the RSB - Trace the per-CPU host save area as a VMCB pointer to improve readability and cleanup the retrieval of the SEV-ES host save area - Remove unnecessary accounting of temporary nested VMCB related allocations - Set FINAL/PAGE in the page fault error code for EPT violations if and only if the GVA is valid. If the GVA is NOT valid, there is no guest-side page table walk and so stuffing paging related metadata is nonsensical - Fix a bug where KVM would incorrectly synthesize a nested VM-Exit instead of emulating posted interrupt delivery to L2 - Add a lockdep assertion to detect unsafe accesses of vmcs12 structures - Harden eVMCS loading against an impossible NULL pointer deref (really truly should be impossible) - Minor SGX fix and a cleanup - Misc cleanups Generic: - Register KVM's cpuhp and syscore callbacks when enabling virtualization in hardware, as the sole purpose of said callbacks is to disable and re-enable virtualization as needed - Enable virtualization when KVM is loaded, not right before the first VM is created Together with the previous change, this simplifies a lot the logic of the callbacks, because their very existence implies virtualization is enabled - Fix a bug that results in KVM prematurely exiting to userspace for coalesced MMIO/PIO in many cases, clean up the related code, and add a testcase - Fix a bug in kvm_clear_guest() where it would trigger a buffer overflow _if_ the gpa+len crosses a page boundary, which thankfully is guaranteed to not happen in the current code base. Add WARNs in more helpers that read/write guest memory to detect similar bugs Selftests: - Fix a goof that caused some Hyper-V tests to be skipped when run on bare metal, i.e. NOT in a VM - Add a regression test for KVM's handling of SHUTDOWN for an SEV-ES guest - Explicitly include one-off assets in .gitignore. Past Sean was completely wrong about not being able to detect missing .gitignore entries - Verify userspace single-stepping works when KVM happens to handle a VM-Exit in its fastpath - Misc cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (127 commits) Documentation: KVM: fix warning in "make htmldocs" s390: Enable KVM_S390_UCONTROL config in debug_defconfig selftests: kvm: s390: Add VM run test case KVM: SVM: let alternatives handle the cases when RSB filling is required KVM: VMX: Set PFERR_GUEST_{FINAL,PAGE}_MASK if and only if the GVA is valid KVM: x86/mmu: Use KVM_PAGES_PER_HPAGE() instead of an open coded equivalent KVM: x86/mmu: Add KVM_RMAP_MANY to replace open coded '1' and '1ul' literals KVM: x86/mmu: Fold mmu_spte_age() into kvm_rmap_age_gfn_range() KVM: x86/mmu: Morph kvm_handle_gfn_range() into an aging specific helper KVM: x86/mmu: Honor NEED_RESCHED when zapping rmaps and blocking is allowed KVM: x86/mmu: Add a helper to walk and zap rmaps for a memslot KVM: x86/mmu: Plumb a @can_yield parameter into __walk_slot_rmaps() KVM: x86/mmu: Move walk_slot_rmaps() up near for_each_slot_rmap_range() KVM: x86/mmu: WARN on MMIO cache hit when emulating write-protected gfn KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list KVM: x86/mmu: Subsume kvm_mmu_unprotect_page() into the and_retry() version KVM: x86: Rename reexecute_instruction()=>kvm_unprotect_and_retry_on_failure() KVM: x86: Update retry protection fields when forcing retry on emulation failure KVM: x86: Apply retry protection to "unprotect on failure" path KVM: x86: Check EMULTYPE_WRITE_PF_TO_SP before unprotecting gfn ...
2024-09-12x86/cpu: fix unbootable VMs by inlining memcmp() in hypervisor_cpuid_base()Alexey Dobriyan
If this memcmp() is not inlined then PVH early boot code can call into KASAN-instrumented memcmp() which results in unbootable VMs: pvh_start_xen xen_prepare_pvh xen_cpuid_base hypervisor_cpuid_base memcmp Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Juergen Gross <jgross@suse.com> Message-ID: <20240802154253.482658-2-adobriyan@gmail.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2024-08-22KVM: x86: Advertise AVX10.1 CPUID to userspaceTao Su
Advertise AVX10.1 related CPUIDs, i.e. report AVX10 support bit via CPUID.(EAX=07H, ECX=01H):EDX[bit 19] and new CPUID leaf 0x24H so that guest OS and applications can query the AVX10.1 CPUIDs directly. Intel AVX10 represents the first major new vector ISA since the introduction of Intel AVX512, which will establish a common, converged vector instruction set across all Intel architectures[1]. AVX10.1 is an early version of AVX10, that enumerates the Intel AVX512 instruction set at 128, 256, and 512 bits which is enabled on Granite Rapids. I.e., AVX10.1 is only a new CPUID enumeration with no new functionality. New features, e.g. Embedded Rounding and Suppress All Exceptions (SAE) will be introduced in AVX10.2. Advertising AVX10.1 is safe because there is nothing to enable for AVX10.1, i.e. it's purely a new way to enumerate support, thus there will never be anything for the kernel to enable. Note just the CPUID checking is changed when using AVX512 related instructions, e.g. if using one AVX512 instruction needs to check (AVX512 AND AVX512DQ), it can check ((AVX512 AND AVX512DQ) OR AVX10.1) after checking XCR0[7:5]. The versions of AVX10 are expected to be inclusive, e.g. version N+1 is a superset of version N. Per the spec, the version can never be 0, just advertise AVX10.1 if it's supported in hardware. Moreover, advertising AVX10_{128,256,512} needs to land in the same commit as advertising basic AVX10.1 support, otherwise KVM would advertise an impossible CPU model. E.g. a CPU with AVX512 but not AVX10.1/512 is impossible per the SDM. As more and more AVX related CPUIDs are added (it would have resulted in around 40-50 CPUID flags when developing AVX10), the versioning approach is introduced. But incrementing version numbers are bad for virtualization. E.g. if AVX10.2 has a feature that shouldn't be enumerated to guests for whatever reason, then KVM can't enumerate any "later" features either, because the only way to hide the problematic AVX10.2 feature is to set the version to AVX10.1 or lower[2]. But most AVX features are just passed through and don't have virtualization controls, so AVX10 should not be problematic in practice, so long as Intel honors their promise that future versions will be supersets of past versions. [1] https://cdrdv2.intel.com/v1/dl/getContent/784267 [2] https://lore.kernel.org/all/Zkz5Ak0PQlAN8DxK@google.com/ Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Tao Su <tao1.su@linux.intel.com> Link: https://lore.kernel.org/r/20240819062327.3269720-1-tao1.su@linux.intel.com [sean: minor changelog tweaks] Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-15x86/cpu: Provide cpuid_read() et al.Thomas Gleixner
Provide a few helper functions to read CPUID leafs or individual registers into a data structure without requiring unions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Juergen Gross <jgross@suse.com> Tested-by: Sohil Mehta <sohil.mehta@intel.com> Tested-by: Michael Kelley <mhklinux@outlook.com> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Zhang Rui <rui.zhang@intel.com> Tested-by: Wang Wendy <wendy.wang@intel.com> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/878r3mg570.ffs@tglx
2022-11-29x86/cpuid: Carve out all CPUID functionalityBorislav Petkov
Carve it out into a special header, where it belongs. No functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20221124164150.3040-1-bp@alien8.de
2022-04-07KVM: x86: Move lookup of indexed CPUID leafs to helperMichael Roth
Determining which CPUID leafs have significant ECX/index values is also needed by guest kernel code when doing SEV-SNP-validated CPUID lookups. Move this to common code to keep future updates in sync. Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Link: https://lore.kernel.org/r/20220307213356.2797205-31-brijesh.singh@amd.com