Commit a836839c authored by Hou Wenlong's avatar Hou Wenlong Committed by Paolo Bonzini
Browse files

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



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: fb6d4d34 ("KVM: x86: emulate RDPID")
Signed-off-by: default avatarHou Wenlong <houwenlong.hwl@antgroup.com>
Message-Id: <1dfd46ae5b76d3ed87bde3154d51c64ea64c99c1.1646226788.git.houwenlong.hwl@antgroup.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e644896f

arch/x86/kvm/emulate.c

+3 −1
Original line number Diff line number Diff line
@@ -3521,8 +3521,10 @@ 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;

}

arch/x86/kvm/kvm_emulate.h

+1 −0
Original line number Diff line number Diff line
@@ -226,6 +226,7 @@ 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);

arch/x86/kvm/x86.c

+6 −0
Original line number Diff line number Diff line
@@ -7728,6 +7728,11 @@ 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_raw(emul_to_vcpu(ctxt), reg);
@@ -7810,6 +7815,7 @@ 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,

	.exiting_smm         = emulator_exiting_smm,