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Commit 674ea351 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: optimize check for valid PAT value 



This check will soon be done on every nested vmentry and vmexit,
"parallelize" it using bitwise operations.

Reviewed-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f16cb57b

arch/x86/kvm/mtrr.c

+1 −9
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/x86.h

+10 −0
Original line number Diff line number Diff line
@@ -347,6 +347,16 @@ 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 & 0xF8F8F8F8F8F8F8F8ull)

		return false;

	/* 0, 1, 4, 5, 6, 7 are valid values.  */

	return (data | ((data & 0x0202020202020202ull) << 1)) == data;

}



void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu);

void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu);



#endif