Commit bdaff4f9 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: x86: Open code vendor_intel() in string_registers_quirk() 

Open code the is_guest_vendor_intel() check in string_registers_quirk() to
discourage makiking exact vendor==Intel checks in the emulator, and to
remove the rather awful #ifdeffery.

The string quirk is literally the only Intel specific, *non-architectural*
behavior that KVM emulates.  All Intel specific behavior that is
architecturally defined applies to all vendors that are compatible with
Intel's architecture, i.e. should use guest_cpuid_is_intel_compatible().

Link: https://lore.kernel.org/r/20240405235603.1173076-10-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 4067c239

arch/x86/kvm/emulate.c

+8 −12
Original line number Diff line number Diff line
@@ -2354,17 +2354,6 @@ setup_syscalls_segments(struct desc_struct *cs, struct desc_struct *ss) 
	ss->avl = 0;

}



#ifdef CONFIG_X86_64

static bool vendor_intel(struct x86_emulate_ctxt *ctxt)

{

	u32 eax, ebx, ecx, edx;



	eax = ecx = 0;

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

	return is_guest_vendor_intel(ebx, ecx, edx);

}

#endif



static int em_syscall(struct x86_emulate_ctxt *ctxt)

{

	const struct x86_emulate_ops *ops = ctxt->ops;
@@ -2622,7 +2611,14 @@ static void string_registers_quirk(struct x86_emulate_ctxt *ctxt) 
	 * manner when ECX is zero due to REP-string optimizations.

	 */

#ifdef CONFIG_X86_64

	if (ctxt->ad_bytes != 4 || !vendor_intel(ctxt))

	u32 eax, ebx, ecx, edx;



	if (ctxt->ad_bytes != 4)

		return;



	eax = ecx = 0;

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

	if (!is_guest_vendor_intel(ebx, ecx, edx))

		return;



	*reg_write(ctxt, VCPU_REGS_RCX) = 0;