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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: Avi Kivity <avi@redhat.com>
hifive-unleashed-5.1
Avi Kivity 2012-06-07 14:07:48 +03:00
parent d881e6f6cf
commit 62046e5a86
2 changed files with 23 additions and 18 deletions
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40
arch/x86/kvm/cpuid.c
View File

@ -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);

1
arch/x86/kvm/cpuid.h
View File

@ -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)