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KVM: x86: Add dedicated emulator helpers for querying CPUID features

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Add feature-specific helpers for querying guest CPUID support from the
emulator instead of having the emulator do a full CPUID and perform its
own bit tests.  The primary motivation is to eliminate the emulator's
usage of bit() so that future patches can add more extensive build-time
assertions on the usage of bit() without having to expose yet more code
to the emulator.

Note, providing a generic guest_cpuid_has() to the emulator doesn't work
due to the existing built-time assertions in guest_cpuid_has(), which
require the feature being checked to be a compile-time constant.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2019-12-17 13:32:38 -08:00
committed by Paolo Bonzini
parent 345599f9a2
commit 5ae78e95ed
3 changed files with 25 additions and 18 deletions
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21
arch/x86/kvm/emulate.c
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@@ -2348,12 +2348,7 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt)
static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt)
{
#ifdef CONFIG_X86_64
u32 eax, ebx, ecx, edx;
eax = 0x80000001;
ecx = 0;
ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false);
return edx & bit(X86_FEATURE_LM);
return ctxt->ops->guest_has_long_mode(ctxt);
#else
return false;
#endif
@@ -3618,18 +3613,11 @@ static int em_mov(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
#define FFL(x) bit(X86_FEATURE_##x)
static int em_movbe(struct x86_emulate_ctxt *ctxt)
{
u32 ebx, ecx, edx, eax = 1;
u16 tmp;
/*
* Check MOVBE is set in the guest-visible CPUID leaf.
*/
ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false);
if (!(ecx & FFL(MOVBE)))
if (!ctxt->ops->guest_has_movbe(ctxt))
return emulate_ud(ctxt);
switch (ctxt->op_bytes) {
@@ -4027,10 +4015,7 @@ static int em_movsxd(struct x86_emulate_ctxt *ctxt)
static int check_fxsr(struct x86_emulate_ctxt *ctxt)
{
u32 eax = 1, ebx, ecx = 0, edx;
ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false);
if (!(edx & FFL(FXSR)))
if (!ctxt->ops->guest_has_fxsr(ctxt))
return emulate_ud(ctxt);
if (ctxt->ops->get_cr(ctxt, 0) & (X86_CR0_TS | X86_CR0_EM))