Commit 0017f93a authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: x86 emulator: change ->get_cpuid() accessor to use the x86 semantics 



Instead of getting an exact leaf, follow the spec and fall back to the last
main leaf instead.  This lets us easily emulate the cpuid instruction in the
emulator.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 62046e5a

arch/x86/include/asm/kvm_emulate.h

+2 −2
Original line number Diff line number Diff line
@@ -192,7 +192,7 @@ struct x86_emulate_ops { 
			 struct x86_instruction_info *info,

			 enum x86_intercept_stage stage);



	bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt,

	void (*get_cpuid)(struct x86_emulate_ctxt *ctxt,

			  u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);

};

arch/x86/kvm/emulate.c

+26 −27
Original line number Diff line number Diff line
@@ -1993,8 +1993,8 @@ static bool vendor_intel(struct x86_emulate_ctxt *ctxt) 
	u32 eax, ebx, ecx, edx;



	eax = ecx = 0;

	return ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)

		&& ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx

	ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx);

	return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx

		&& ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx

		&& edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx;

}
@@ -2013,7 +2013,7 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) 


	eax = 0x00000000;

	ecx = 0x00000000;

	if (ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)) {

	ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx);

	/*

	 * Intel ("GenuineIntel")

	 * remark: Intel CPUs only support "syscall" in 64bit
@@ -2038,7 +2038,6 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) 
	    ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&

	    edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx)

		return true;

	}



	/* default: (not Intel, not AMD), apply Intel's stricter rules... */

	return false;

arch/x86/kvm/x86.c

+2 −18
Original line number Diff line number Diff line
@@ -4302,26 +4302,10 @@ static int emulator_intercept(struct x86_emulate_ctxt *ctxt, 
	return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage);

}



static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,

static void emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,

			       u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)

{

	struct kvm_cpuid_entry2 *cpuid = NULL;



	if (eax && ecx)

		cpuid = kvm_find_cpuid_entry(emul_to_vcpu(ctxt),

					    *eax, *ecx);



	if (cpuid) {

		*eax = cpuid->eax;

		*ecx = cpuid->ecx;

		if (ebx)

			*ebx = cpuid->ebx;

		if (edx)

			*edx = cpuid->edx;

		return true;

	}



	return false;

	kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx);

}



static struct x86_emulate_ops emulate_ops = {

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