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SubjectRe: [PATCH 49/61] KVM: x86: Override host CPUID results with kvm_cpu_caps
Date
Sean Christopherson <sean.j.christopherson@intel.com> writes:

> Override CPUID entries with kvm_cpu_caps during KVM_GET_SUPPORTED_CPUID
> instead of masking the host CPUID result, which is redundant now that
> the host CPUID is incorporated into kvm_cpu_caps at runtime.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
> arch/x86/kvm/cpuid.c | 28 ++++++++++++++--------------
> 1 file changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 4416f2422321..871c0bd04e19 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -261,13 +261,13 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
> return r;
> }
>
> -static __always_inline void cpuid_entry_mask(struct kvm_cpuid_entry2 *entry,
> - enum cpuid_leafs leaf)
> +static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry,
> + enum cpuid_leafs leaf)
> {
> u32 *reg = cpuid_entry_get_reg(entry, leaf * 32);
>
> BUILD_BUG_ON(leaf > ARRAY_SIZE(kvm_cpu_caps));
> - *reg &= kvm_cpu_caps[leaf];
> + *reg = kvm_cpu_caps[leaf];
> }
>
> static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
> @@ -488,8 +488,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> entry->eax = min(entry->eax, 0x1fU);
> break;
> case 1:
> - cpuid_entry_mask(entry, CPUID_1_EDX);
> - cpuid_entry_mask(entry, CPUID_1_ECX);
> + cpuid_entry_override(entry, CPUID_1_EDX);
> + cpuid_entry_override(entry, CPUID_1_ECX);
> /* we support x2apic emulation even if host does not support
> * it since we emulate x2apic in software */
> cpuid_entry_set(entry, X86_FEATURE_X2APIC);
> @@ -543,9 +543,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> /* function 7 has additional index. */
> case 7:
> entry->eax = min(entry->eax, 1u);
> - cpuid_entry_mask(entry, CPUID_7_0_EBX);
> - cpuid_entry_mask(entry, CPUID_7_ECX);
> - cpuid_entry_mask(entry, CPUID_7_EDX);
> + cpuid_entry_override(entry, CPUID_7_0_EBX);
> + cpuid_entry_override(entry, CPUID_7_ECX);
> + cpuid_entry_override(entry, CPUID_7_EDX);
>
> /* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
> cpuid_entry_set(entry, X86_FEATURE_TSC_ADJUST);
> @@ -564,7 +564,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> if (!entry)
> goto out;
>
> - cpuid_entry_mask(entry, CPUID_7_1_EAX);
> + cpuid_entry_override(entry, CPUID_7_1_EAX);
> entry->ebx = 0;
> entry->ecx = 0;
> entry->edx = 0;
> @@ -630,7 +630,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> if (!entry)
> goto out;
>
> - cpuid_entry_mask(entry, CPUID_D_1_EAX);
> + cpuid_entry_override(entry, CPUID_D_1_EAX);
> if (entry->eax & (F(XSAVES)|F(XSAVEC)))
> entry->ebx = xstate_required_size(supported_xcr0, true);
> else
> @@ -709,8 +709,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> entry->eax = min(entry->eax, 0x8000001f);
> break;
> case 0x80000001:
> - cpuid_entry_mask(entry, CPUID_8000_0001_EDX);
> - cpuid_entry_mask(entry, CPUID_8000_0001_ECX);
> + cpuid_entry_override(entry, CPUID_8000_0001_EDX);
> + cpuid_entry_override(entry, CPUID_8000_0001_ECX);
> break;
> case 0x80000007: /* Advanced power management */
> /* invariant TSC is CPUID.80000007H:EDX[8] */
> @@ -728,7 +728,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> g_phys_as = phys_as;
> entry->eax = g_phys_as | (virt_as << 8);
> entry->edx = 0;
> - cpuid_entry_mask(entry, CPUID_8000_0008_EBX);
> + cpuid_entry_override(entry, CPUID_8000_0008_EBX);
> /*
> * AMD has separate bits for each SPEC_CTRL bit.
> * arch/x86/kernel/cpu/bugs.c is kind enough to
> @@ -770,7 +770,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
> entry->eax = min(entry->eax, 0xC0000004);
> break;
> case 0xC0000001:
> - cpuid_entry_mask(entry, CPUID_C000_0001_EDX);
> + cpuid_entry_override(entry, CPUID_C000_0001_EDX);
> break;
> case 3: /* Processor serial number */
> case 5: /* MONITOR/MWAIT */

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

--
Vitaly

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