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: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 1ac46c22dd5003d90fd253497be9378d8fd3da8a..cd5c96b2496e726c429ea0d27b27540934a91aef 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -192,8 +192,8 @@ struct x86_emulate_ops {
                         struct x86_instruction_info *info,
                         enum x86_intercept_stage stage);
 
-       bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
-                        u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
+       void (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
+                         u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
 };
 
 typedef u32 __attribute__((vector_size(16))) sse128_t;

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index f95d242ee9f72a8f30bf912cf81dd172745dadd9..ba1f8ecaab52c447e3bccd5ebc2cf44ecab7eda0 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -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;
 }
@@ -2013,32 +2013,31 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt)
 
        eax = 0x00000000;
        ecx = 0x00000000;
-       if (ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)) {
-               /*
-                * Intel ("GenuineIntel")
-                * remark: Intel CPUs only support "syscall" in 64bit
-                * longmode. Also an 64bit guest with a
-                * 32bit compat-app running will #UD !! While this
-                * behaviour can be fixed (by emulating) into AMD
-                * response - CPUs of AMD can't behave like Intel.
-                */
-               if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
-                   ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
-                   edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx)
-                       return false;
+       ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx);
+       /*
+        * Intel ("GenuineIntel")
+        * remark: Intel CPUs only support "syscall" in 64bit
+        * longmode. Also an 64bit guest with a
+        * 32bit compat-app running will #UD !! While this
+        * behaviour can be fixed (by emulating) into AMD
+        * response - CPUs of AMD can't behave like Intel.
+        */
+       if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
+           ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
+           edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx)
+               return false;
 
-               /* AMD ("AuthenticAMD") */
-               if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
-                   ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
-                   edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx)
-                       return true;
-
-               /* AMD ("AMDisbetter!") */
-               if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
-                   ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
-                   edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx)
-                       return true;
-       }
+       /* AMD ("AuthenticAMD") */
+       if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
+           ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
+           edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx)
+               return true;
+
+       /* AMD ("AMDisbetter!") */
+       if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
+           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;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8eacb2e645608ee79ca9826072c68929888b9d96..ff0b487e725400fc939321498853ebe45200c9d2 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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 = {