leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

KVM: vmx: VMXOFF emulation in vm86 should cause #UD

Browse Source 
Unlike VMCALL, the instructions VMXOFF, VMLAUNCH and VMRESUME should cause a UD
exception in real-mode or vm86.  However, the emulator considers all these
instructions the same for the matter of mode checks, and emulation upon exit
due to #UD exception.

As a result, the hypervisor behaves incorrectly on vm86 mode. VMXOFF, VMLAUNCH
or VMRESUME cause on vm86 exit due to #UD. The hypervisor then emulates these
instruction and inject #GP to the guest instead of #UD.

This patch creates a new group for these instructions and mark only VMCALL as
an instruction which can be emulated.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nadav Amit 2014-08-29 11:26:55 +03:00 committed by Paolo Bonzini
parent 48d89b9260
commit 0f54a32130
1 changed files with 8 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
arch/x86/kvm/emulate.c
View File

@ -3139,12 +3139,8 @@ static int em_clts(struct x86_emulate_ctxt *ctxt)
static int em_vmcall(struct x86_emulate_ctxt *ctxt)
{
int rc;
int rc = ctxt->ops->fix_hypercall(ctxt);
if (ctxt->modrm_mod != 3 || ctxt->modrm_rm != 1)
return X86EMUL_UNHANDLEABLE;
rc = ctxt->ops->fix_hypercall(ctxt);
if (rc != X86EMUL_CONTINUE)
return rc;
@ -3562,6 +3558,12 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
F2bv(((_f) | DstReg | SrcMem | ModRM) & ~Lock, _e), \
F2bv(((_f) & ~Lock) | DstAcc | SrcImm, _e)
static const struct opcode group7_rm0[] = {
N,
I(SrcNone | Priv | EmulateOnUD, em_vmcall),
N, N, N, N, N, N,
};
static const struct opcode group7_rm1[] = {
DI(SrcNone | Priv, monitor),
DI(SrcNone | Priv, mwait),
@ -3655,7 +3657,7 @@ static const struct group_dual group7 = { {
II(SrcMem16 | Mov | Priv, em_lmsw, lmsw),
II(SrcMem | ByteOp | Priv | NoAccess, em_invlpg, invlpg),
}, {
I(SrcNone | Priv | EmulateOnUD, em_vmcall),
EXT(0, group7_rm0),
EXT(0, group7_rm1),
N, EXT(0, group7_rm3),
II(SrcNone | DstMem | Mov, em_smsw, smsw), N,