Messages in this thread | | | Subject | Re: [PATCH] KVM: x86: optimize check for valid PAT value | From | Krish Sadhukhan <> | Date | Wed, 10 Apr 2019 16:36:36 -0700 |
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On 04/10/2019 02:55 AM, Paolo Bonzini wrote: > This check will soon be done on every nested vmentry and vmexit, > "parallelize" it using bitwise operations. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > arch/x86/kvm/mtrr.c | 10 +--------- > arch/x86/kvm/vmx/vmx.c | 2 +- > arch/x86/kvm/x86.h | 8 ++++++++ > 3 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c > index e9ea2d45ae66..9f72cc427158 100644 > --- a/arch/x86/kvm/mtrr.c > +++ b/arch/x86/kvm/mtrr.c > @@ -48,11 +48,6 @@ static bool msr_mtrr_valid(unsigned msr) > return false; > } > > -static bool valid_pat_type(unsigned t) > -{ > - return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */ > -} > - > static bool valid_mtrr_type(unsigned t) > { > return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */ > @@ -67,10 +62,7 @@ bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data) > return false; > > if (msr == MSR_IA32_CR_PAT) { > - for (i = 0; i < 8; i++) > - if (!valid_pat_type((data >> (i * 8)) & 0xff)) > - return false; > - return true; > + return kvm_pat_valid(data); > } else if (msr == MSR_MTRRdefType) { > if (data & ~0xcff) > return false; > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index b6c533afbf27..b74679732cfc 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -1891,7 +1891,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > break; > case MSR_IA32_CR_PAT: > if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) { > - if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data)) > + if (!kvm_pat_valid(data)) > return 1; > vmcs_write64(GUEST_IA32_PAT, data); > vcpu->arch.pat = data; > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 28406aa1136d..7bc7ac9d2a44 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -347,4 +347,12 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) > __this_cpu_write(current_vcpu, NULL); > } > > +static inline bool kvm_pat_valid(u64 data) > +{ > + if (data & 0xF8F8F8F8F8F8F8F8) > + return false; > + /* 0, 1, 4, 5, 6, 7 are valid values. */ > + return (data | ((data & 0x0202020202020202) << 1)) == data; > +} > + > #endif
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
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