From bdaff4f92bcee7a6205f3544bb94e2d16ad98f6b Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 5 Apr 2024 16:56:02 -0700 Subject: [PATCH] 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: Sean Christopherson --- arch/x86/kvm/emulate.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 26e8c197a1d16..1acd97c6fa536 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -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;