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KVM: x86/emulator: Emulate RDPID only if it is enabled in guest

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[ Upstream commit a836839cbfe60dc434c5476a7429cf2bae36415d ]

When RDTSCP is supported but RDPID is not supported in host,
RDPID emulation is available. However, __kvm_get_msr() would
only fail when RDTSCP/RDPID both are disabled in guest, so
the emulator wouldn't inject a #UD when RDPID is disabled but
RDTSCP is enabled in guest.

Fixes: fb6d4d340e05 ("KVM: x86: emulate RDPID")
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Message-Id: <1dfd46ae5b76d3ed87bde3154d51c64ea64c99c1.1646226788.git.houwenlong.hwl@antgroup.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Hou Wenlong 2022-03-02 21:15:14 +08:00 committed by Greg Kroah-Hartman
parent 66b0fa6b22
commit a24479c5e9
3 changed files with 10 additions and 1 deletions

4
arch/x86/kvm/emulate.c

@ -3611,8 +3611,10 @@ static int em_rdpid(struct x86_emulate_ctxt *ctxt)
{
u64 tsc_aux = 0;
if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux))
if (!ctxt->ops->guest_has_rdpid(ctxt))
return emulate_ud(ctxt);
ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux);
ctxt->dst.val = tsc_aux;
return X86EMUL_CONTINUE;
}

1
arch/x86/kvm/kvm_emulate.h

@ -225,6 +225,7 @@ struct x86_emulate_ops {
bool (*guest_has_long_mode)(struct x86_emulate_ctxt *ctxt);
bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt);
bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt);
bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt);
void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);

6
arch/x86/kvm/x86.c

@ -6875,6 +6875,11 @@ static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt)
return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_FXSR);
}
static bool emulator_guest_has_rdpid(struct x86_emulate_ctxt *ctxt)
{
return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_RDPID);
}
static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
{
return kvm_register_read(emul_to_vcpu(ctxt), reg);
@ -6958,6 +6963,7 @@ static const struct x86_emulate_ops emulate_ops = {
.guest_has_long_mode = emulator_guest_has_long_mode,
.guest_has_movbe = emulator_guest_has_movbe,
.guest_has_fxsr = emulator_guest_has_fxsr,
.guest_has_rdpid = emulator_guest_has_rdpid,
.set_nmi_mask = emulator_set_nmi_mask,
.get_hflags = emulator_get_hflags,
.set_hflags = emulator_set_hflags,