From 0f54a321302dfbdbd707ba989b2f468e58b9a363 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Fri, 29 Aug 2014 11:26:55 +0300 Subject: [PATCH] KVM: vmx: VMXOFF emulation in vm86 should cause #UD 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 Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index e5bf13003cd2..a240fac29e76 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3139,12 +3139,8 @@ static int em_clts(struct x86_emulate_ctxt *ctxt) static int em_vmcall(struct x86_emulate_ctxt *ctxt) { - int rc; - - if (ctxt->modrm_mod != 3 || ctxt->modrm_rm != 1) - return X86EMUL_UNHANDLEABLE; + int rc = ctxt->ops->fix_hypercall(ctxt); - 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, -- 2.11.0