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authorAvi Kivity <avi@redhat.com>2012-02-01 12:23:21 +0200
committerAvi Kivity <avi@redhat.com>2012-03-05 14:57:20 +0200
commit1a18a69b762374c423305772500f36eb8984ca52 (patch)
treedf0c7276bac2b3899a7d033fa24783e84e7817ab
parenta52315e1d549dad80ff443151927226c11fd8c2b (diff)
downloadlinux-linaro-stable-1a18a69b762374c423305772500f36eb8984ca52.tar.gz
KVM: x86 emulator: reject SYSENTER in compatibility mode on AMD guests
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@redhat.com>
-rw-r--r--arch/x86/kvm/emulate.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 6eaedac7cf6a..71450aca3b86 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1892,6 +1892,17 @@ setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
ss->p = 1;
}
+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
+ && 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 +2019,14 @@ 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.
*/