If the guest thinks it's an AMD, it will not have prepared the SYSENTER MSRs,
and if the guest executes SYSENTER in compatibility mode, it will fails.
Detect this condition and #UD instead, like the spec says.
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 6eaedac..367bd06 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1892,6 +1892,16 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt)
ss->p = 1;
}
+static bool vendor_intel(struct x86_emulate_ctxt *ctxt)
+{
+ u32 eax, ebx, ecx, edx;
+
+ return ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)
+ && ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx
+ && ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx
+ && edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx;
+}
+
static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt)
{
struct x86_emulate_ops *ops = ctxt->ops;
@@ -2008,6 +2018,14 @@ static int em_sysenter(struct x86_emulate_ctxt *ctxt)
if (ctxt->mode == X86EMUL_MODE_REAL)
return emulate_gp(ctxt, 0);
+ /*
+ * Not recognized on AMD in compat mode (but is recognized in legacy
+ * mode).
+ */
+ if ((ctxt->mode == X86EMUL_MODE_PROT32) && (efer & EFER_LMA)
+ && !vendor_intel(ctxt))
+ return emulate_ud(ctxt);
+
/* XXX sysenter/sysexit have not been tested in 64bit mode.
* Therefore, we inject an #UD.
*/
--
1.7.9
--
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