KVM: emulator: Do not fail on emulation of undefined opcode

[linux-2.6-block.git] / arch / x86 / kvm / emulate.c

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a335cc6cde72aa099cbd718bfc02a71c3d70feb2..77b56d5be3e146a5fc149971d5a57e20dfc69925 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -132,8 +132,9 @@
 #define Priv        (1<<27) /* instruction generates #GP if current CPL != 0 */
 #define No64       (1<<28)
 #define PageTable   (1 << 29)   /* instruction used to write page table */
+#define NotImpl     (1 << 30)   /* instruction is not implemented */
 /* Source 2 operand type */
-#define Src2Shift   (30)
+#define Src2Shift   (31)
 #define Src2None    (OpNone << Src2Shift)
 #define Src2CL      (OpCL << Src2Shift)
 #define Src2ImmByte (OpImmByte << Src2Shift)
@@ -1578,12 +1579,21 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 
        memset(&seg_desc, 0, sizeof seg_desc);
 
-       if ((seg <= VCPU_SREG_GS && ctxt->mode == X86EMUL_MODE_VM86)
-           || ctxt->mode == X86EMUL_MODE_REAL) {
-               /* set real mode segment descriptor */
+       if (ctxt->mode == X86EMUL_MODE_REAL) {
+               /* set real mode segment descriptor (keep limit etc. for
+                * unreal mode) */
                ctxt->ops->get_segment(ctxt, &dummy, &seg_desc, NULL, seg);
                set_desc_base(&seg_desc, selector << 4);
                goto load;
+       } else if (seg <= VCPU_SREG_GS && ctxt->mode == X86EMUL_MODE_VM86) {
+               /* VM86 needs a clean new segment descriptor */
+               set_desc_base(&seg_desc, selector << 4);
+               set_desc_limit(&seg_desc, 0xffff);
+               seg_desc.type = 3;
+               seg_desc.p = 1;
+               seg_desc.s = 1;
+               seg_desc.dpl = 3;
+               goto load;
        }
 
        rpl = selector & 3;
@@ -3615,7 +3625,7 @@ static int check_perm_out(struct x86_emulate_ctxt *ctxt)
 #define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
 #define DIP(_y, _i, _p) { .flags = (_y), .intercept = x86_intercept_##_i, \
                      .check_perm = (_p) }
-#define N    D(0)
+#define N    D(NotImpl)
 #define EXT(_f, _e) { .flags = ((_f) | RMExt), .u.group = (_e) }
 #define G(_f, _g) { .flags = ((_f) | Group | ModRM), .u.group = (_g) }
 #define GD(_f, _g) { .flags = ((_f) | GroupDual | ModRM), .u.gdual = (_g) }
@@ -4373,7 +4383,7 @@ done_prefixes:
        ctxt->intercept = opcode.intercept;
 
        /* Unrecognised? */
-       if (ctxt->d == 0 || (ctxt->d & Undefined))
+       if (ctxt->d == 0 || (ctxt->d & NotImpl))
                return EMULATION_FAILED;
 
        if (!(ctxt->d & VendorSpecific) && ctxt->only_vendor_specific_insn)
@@ -4511,7 +4521,8 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
 
        ctxt->mem_read.pos = 0;
 
-       if (ctxt->mode == X86EMUL_MODE_PROT64 && (ctxt->d & No64)) {
+       if ((ctxt->mode == X86EMUL_MODE_PROT64 && (ctxt->d & No64)) ||
+                       (ctxt->d & Undefined)) {
                rc = emulate_ud(ctxt);
                goto done;
        }