KVM: x86 emulator: implement rdmsr and wrmsr

Allow real-mode emulation of rdmsr and wrmsr.  This allows smp Windows to
boot, presumably for its sipi trampoline.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index f60012d62610..1b800fc00342 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -163,7 +163,7 @@ static u16 twobyte_table[256] = {
         ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0,
         /* 0x30 - 0x3F */
-        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        ImplicitOps, 0, ImplicitOps, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         /* 0x40 - 0x47 */
         DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
         DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
@@ -486,6 +486,7 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         unsigned long modrm_ea;
         int use_modrm_ea, index_reg = 0, base_reg = 0, scale, rip_relative = 0;
         int no_wb = 0;
+        u64 msr_data;
 
         /* Shadow copy of register state. Committed on successful emulation. */
         unsigned long _regs[NR_VCPU_REGS];
@@ -1344,6 +1345,29 @@ twobyte_special_insn:
                         goto cannot_emulate;
                 realmode_set_cr(ctxt->vcpu, modrm_reg, modrm_val, &_eflags);
                 break;
+        case 0x30:
+                /* wrmsr */
+                msr_data = (u32)_regs[VCPU_REGS_RAX]
+                        | ((u64)_regs[VCPU_REGS_RDX] << 32);
+                rc = kvm_set_msr(ctxt->vcpu, _regs[VCPU_REGS_RCX], msr_data);
+                if (rc) {
+                        kvm_arch_ops->inject_gp(ctxt->vcpu, 0);
+                        _eip = ctxt->vcpu->rip;
+                }
+                rc = X86EMUL_CONTINUE;
+                break;
+        case 0x32:
+                /* rdmsr */
+                rc = kvm_get_msr(ctxt->vcpu, _regs[VCPU_REGS_RCX], &msr_data);
+                if (rc) {
+                        kvm_arch_ops->inject_gp(ctxt->vcpu, 0);
+                        _eip = ctxt->vcpu->rip;
+                } else {
+                        _regs[VCPU_REGS_RAX] = (u32)msr_data;
+                        _regs[VCPU_REGS_RDX] = msr_data >> 32;
+                }
+                rc = X86EMUL_CONTINUE;
+                break;
         case 0xc7:              /* Grp9 (cmpxchg8b) */
                 {
                         u64 old, new;