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Commit 62046e5a authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: Split cpuid register access from computation 



Introduce kvm_cpuid() to perform the leaf limit check and calculate
register values, and let kvm_emulate_cpuid() just handle reading and
writing the registers from/to the vcpu.  This allows us to reuse
kvm_cpuid() in a context where directly reading and writing registers
is not desired.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent d881e6f6

arch/x86/kvm/cpuid.c

+22 −18
Original line number Diff line number Diff line
@@ -640,33 +640,37 @@ static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu, 
	return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);

}



void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)

void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)

{

	u32 function, index;

	u32 function = *eax, index = *ecx;

	struct kvm_cpuid_entry2 *best;



	function = kvm_register_read(vcpu, VCPU_REGS_RAX);

	index = kvm_register_read(vcpu, VCPU_REGS_RCX);

	kvm_register_write(vcpu, VCPU_REGS_RAX, 0);

	kvm_register_write(vcpu, VCPU_REGS_RBX, 0);

	kvm_register_write(vcpu, VCPU_REGS_RCX, 0);

	kvm_register_write(vcpu, VCPU_REGS_RDX, 0);

	best = kvm_find_cpuid_entry(vcpu, function, index);



	if (!best)

		best = check_cpuid_limit(vcpu, function, index);



	if (best) {

		kvm_register_write(vcpu, VCPU_REGS_RAX, best->eax);

		kvm_register_write(vcpu, VCPU_REGS_RBX, best->ebx);

		kvm_register_write(vcpu, VCPU_REGS_RCX, best->ecx);

		kvm_register_write(vcpu, VCPU_REGS_RDX, best->edx);

		*eax = best->eax;

		*ebx = best->ebx;

		*ecx = best->ecx;

		*edx = best->edx;

	} else

		*eax = *ebx = *ecx = *edx = 0;

}



void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)

{

	u32 function, eax, ebx, ecx, edx;



	function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);

	ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);

	kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);

	kvm_register_write(vcpu, VCPU_REGS_RAX, eax);

	kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);

	kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);

	kvm_register_write(vcpu, VCPU_REGS_RDX, edx);

	kvm_x86_ops->skip_emulated_instruction(vcpu);

	trace_kvm_cpuid(function,

			kvm_register_read(vcpu, VCPU_REGS_RAX),

			kvm_register_read(vcpu, VCPU_REGS_RBX),

			kvm_register_read(vcpu, VCPU_REGS_RCX),

			kvm_register_read(vcpu, VCPU_REGS_RDX));

	trace_kvm_cpuid(function, eax, ebx, ecx, edx);

}

EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);

arch/x86/kvm/cpuid.h

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, 
int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,

			      struct kvm_cpuid2 *cpuid,

			      struct kvm_cpuid_entry2 __user *entries);

void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);





static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)