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| author |   Sean Christopherson <seanjc@google.com> | 2024-11-27 17:34:17 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-12-18 14:20:15 -0800 |
| commit | 8f2a27752e808f16f3baf1939a91c42966f22a08 (patch) | |
| tree | 49b9d2fa61755ec819b70754081e43128f8e9231 /arch/x86/kvm/smm.c | |
| parent | KVM: x86: Shuffle code to prepare for dropping guest_cpuid_has() (diff) | |
| download | wireguard-linux-8f2a27752e808f16f3baf1939a91c42966f22a08.tar.xz wireguard-linux-8f2a27752e808f16f3baf1939a91c42966f22a08.zip | |
KVM: x86: Replace (almost) all guest CPUID feature queries with cpu_caps
Switch all queries (except XSAVES) of guest features from guest CPUID to
guest capabilities, i.e. replace all calls to guest_cpuid_has() with calls
to guest_cpu_cap_has().
Keep guest_cpuid_has() around for XSAVES, but subsume its helper
guest_cpuid_get_register() and add a compile-time assertion to prevent
using guest_cpuid_has() for any other feature. Add yet another comment
for XSAVE to explain why KVM is allowed to query its raw guest CPUID.
Opportunistically drop the unused guest_cpuid_clear(), as there should be
no circumstance in which KVM needs to _clear_ a guest CPUID feature now
that everything is tracked via cpu_caps. E.g. KVM may need to _change_
a feature to emulate dynamic CPUID flags, but KVM should never need to
clear a feature in guest CPUID to prevent it from being used by the guest.
Delete the last remnants of the governed features framework, as the lone
holdout was vmx_adjust_secondary_exec_control()'s divergent behavior for
governed vs. ungoverned features.
Note, replacing guest_cpuid_has() checks with guest_cpu_cap_has() when
computing reserved CR4 bits is a nop when viewed as a whole, as KVM's
capabilities are already incorporated into the calculation, i.e. if a
feature is present in guest CPUID but unsupported by KVM, its CR4 bit
was already being marked as reserved, checking guest_cpu_cap_has() simply
double-stamps that it's a reserved bit.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-51-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/smm.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c index 85241c0c7f56..e0ab7df27b66 100644 --- a/arch/x86/kvm/smm.c +++ b/arch/x86/kvm/smm.c @@ -283,7 +283,7 @@ void enter_smm(struct kvm_vcpu *vcpu) memset(smram.bytes, 0, sizeof(smram.bytes)); #ifdef CONFIG_X86_64 - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LM)) enter_smm_save_state_64(vcpu, &smram.smram64); else #endif @@ -353,7 +353,7 @@ void enter_smm(struct kvm_vcpu *vcpu) kvm_set_segment(vcpu, &ds, VCPU_SREG_SS); #ifdef CONFIG_X86_64 - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LM)) if (kvm_x86_call(set_efer)(vcpu, 0)) goto error; #endif @@ -586,7 +586,7 @@ int emulator_leave_smm(struct x86_emulate_ctxt *ctxt) * supports long mode. */ #ifdef CONFIG_X86_64 - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) { + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LM)) { struct kvm_segment cs_desc; unsigned long cr4; @@ -609,7 +609,7 @@ int emulator_leave_smm(struct x86_emulate_ctxt *ctxt) kvm_set_cr0(vcpu, cr0 & ~(X86_CR0_PG | X86_CR0_PE)); #ifdef CONFIG_X86_64 - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) { + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LM)) { unsigned long cr4, efer; /* Clear CR4.PAE before clearing EFER.LME. */ @@ -634,7 +634,7 @@ int emulator_leave_smm(struct x86_emulate_ctxt *ctxt) return X86EMUL_UNHANDLEABLE; #ifdef CONFIG_X86_64 - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) + if (guest_cpu_cap_has(vcpu, X86_FEATURE_LM)) ret = rsm_load_state_64(ctxt, &smram.smram64); else #endif |