| Message ID | 20240517173926.965351-22-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: CPUID overhaul, fixes, and caching | expand |
On Fri, 2024-05-17 at 10:38 -0700, Sean Christopherson wrote: > Add a macro to mask-in feature flags that are supported only on 64-bit > kernels/KVM. In addition to reducing overall #ifdeffery, using a macro > will allow hardening the kvm_cpu_cap initialization sequences to assert > that the features being advertised are indeed included in the word being > initialized. And arguably using *F() macros through is more readable. > > No functional change intended. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/cpuid.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 5a4d6138c4f1..5e3b97d06374 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -70,6 +70,12 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted) > (boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0); \ > }) > > +/* Features that KVM supports only on 64-bit kernels. */ > +#define X86_64_F(name) \ > +({ \ > + (IS_ENABLED(CONFIG_X86_64) ? F(name) : 0); \ > +}) > + > /* > * Raw Feature - For features that KVM supports based purely on raw host CPUID, > * i.e. that KVM virtualizes even if the host kernel doesn't use the feature. > @@ -639,15 +645,6 @@ static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask) > > void kvm_set_cpu_caps(void) > { > -#ifdef CONFIG_X86_64 > - unsigned int f_gbpages = F(GBPAGES); > - unsigned int f_lm = F(LM); > - unsigned int f_xfd = F(XFD); > -#else > - unsigned int f_gbpages = 0; > - unsigned int f_lm = 0; > - unsigned int f_xfd = 0; > -#endif > memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps)); > > BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) > > @@ -744,7 +741,8 @@ void kvm_set_cpu_caps(void) > ); > > kvm_cpu_cap_init(CPUID_D_1_EAX, > - F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd > + F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | > + X86_64_F(XFD) > ); > > kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX, > @@ -766,8 +764,8 @@ void kvm_set_cpu_caps(void) > F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | > F(PAT) | F(PSE36) | 0 /* Reserved */ | > F(NX) | 0 /* Reserved */ | F(MMXEXT) | F(MMX) | > - F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) | > - 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW) > + F(FXSR) | F(FXSR_OPT) | X86_64_F(GBPAGES) | F(RDTSCP) | > + 0 /* Reserved */ | X86_64_F(LM) | F(3DNOWEXT) | F(3DNOW) > ); > > if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64)) This is a good cleanup. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Best regards, Maxim Levitsky
On 5/18/2024 1:38 AM, Sean Christopherson wrote: > Add a macro to mask-in feature flags that are supported only on 64-bit > kernels/KVM. In addition to reducing overall #ifdeffery, using a macro > will allow hardening the kvm_cpu_cap initialization sequences to assert > that the features being advertised are indeed included in the word being > initialized. And arguably using *F() macros through is more readable. > > No functional change intended. > > Signed-off-by: Sean Christopherson <seanjc@google.com> Very nice patch! Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> > --- > arch/x86/kvm/cpuid.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 5a4d6138c4f1..5e3b97d06374 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -70,6 +70,12 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted) > (boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0); \ > }) > > +/* Features that KVM supports only on 64-bit kernels. */ > +#define X86_64_F(name) \ > +({ \ > + (IS_ENABLED(CONFIG_X86_64) ? F(name) : 0); \ > +}) > + > /* > * Raw Feature - For features that KVM supports based purely on raw host CPUID, > * i.e. that KVM virtualizes even if the host kernel doesn't use the feature. > @@ -639,15 +645,6 @@ static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask) > > void kvm_set_cpu_caps(void) > { > -#ifdef CONFIG_X86_64 > - unsigned int f_gbpages = F(GBPAGES); > - unsigned int f_lm = F(LM); > - unsigned int f_xfd = F(XFD); > -#else > - unsigned int f_gbpages = 0; > - unsigned int f_lm = 0; > - unsigned int f_xfd = 0; > -#endif > memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps)); > > BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) > > @@ -744,7 +741,8 @@ void kvm_set_cpu_caps(void) > ); > > kvm_cpu_cap_init(CPUID_D_1_EAX, > - F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd > + F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | > + X86_64_F(XFD) > ); > > kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX, > @@ -766,8 +764,8 @@ void kvm_set_cpu_caps(void) > F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | > F(PAT) | F(PSE36) | 0 /* Reserved */ | > F(NX) | 0 /* Reserved */ | F(MMXEXT) | F(MMX) | > - F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) | > - 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW) > + F(FXSR) | F(FXSR_OPT) | X86_64_F(GBPAGES) | F(RDTSCP) | > + 0 /* Reserved */ | X86_64_F(LM) | F(3DNOWEXT) | F(3DNOW) > ); > > if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5a4d6138c4f1..5e3b97d06374 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -70,6 +70,12 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted) (boot_cpu_has(X86_FEATURE_##name) ? F(name) : 0); \ }) +/* Features that KVM supports only on 64-bit kernels. */ +#define X86_64_F(name) \ +({ \ + (IS_ENABLED(CONFIG_X86_64) ? F(name) : 0); \ +}) + /* * Raw Feature - For features that KVM supports based purely on raw host CPUID, * i.e. that KVM virtualizes even if the host kernel doesn't use the feature. @@ -639,15 +645,6 @@ static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask) void kvm_set_cpu_caps(void) { -#ifdef CONFIG_X86_64 - unsigned int f_gbpages = F(GBPAGES); - unsigned int f_lm = F(LM); - unsigned int f_xfd = F(XFD); -#else - unsigned int f_gbpages = 0; - unsigned int f_lm = 0; - unsigned int f_xfd = 0; -#endif memset(kvm_cpu_caps, 0, sizeof(kvm_cpu_caps)); BUILD_BUG_ON(sizeof(kvm_cpu_caps) - (NKVMCAPINTS * sizeof(*kvm_cpu_caps)) > @@ -744,7 +741,8 @@ void kvm_set_cpu_caps(void) ); kvm_cpu_cap_init(CPUID_D_1_EAX, - F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd + F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | + X86_64_F(XFD) ); kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX, @@ -766,8 +764,8 @@ void kvm_set_cpu_caps(void) F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | F(PAT) | F(PSE36) | 0 /* Reserved */ | F(NX) | 0 /* Reserved */ | F(MMXEXT) | F(MMX) | - F(FXSR) | F(FXSR_OPT) | f_gbpages | F(RDTSCP) | - 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW) + F(FXSR) | F(FXSR_OPT) | X86_64_F(GBPAGES) | F(RDTSCP) | + 0 /* Reserved */ | X86_64_F(LM) | F(3DNOWEXT) | F(3DNOW) ); if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
Add a macro to mask-in feature flags that are supported only on 64-bit kernels/KVM. In addition to reducing overall #ifdeffery, using a macro will allow hardening the kvm_cpu_cap initialization sequences to assert that the features being advertised are indeed included in the word being initialized. And arguably using *F() macros through is more readable. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/cpuid.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-)