KVM: x86 emulator: do not inject exception directly into vcpu

Return exception as a result of instruction emulation and handle
injection in KVM code.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

3 files changed, 100 insertions, 50 deletions

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index a87d95f09572..51cfd730ac5d 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -216,6 +216,12 @@ struct x86_emulate_ctxt {
         int interruptibility;
 
         bool restart; /* restart string instruction after writeback */
+
+        int exception; /* exception that happens during emulation or -1 */
+        u32 error_code; /* error code for exception */
+        bool error_code_valid;
+        unsigned long cr2; /* faulted address in case of #PF */
+
         /* decode cache */
         struct decode_cache decode;
 };
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c40b40561dff..b43ac98ef790 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -653,6 +653,37 @@ static unsigned long ss_base(struct x86_emulate_ctxt *ctxt,
         return seg_base(ctxt, ops, VCPU_SREG_SS);
 }
 
+static void emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
+                                      u32 error, bool valid)
+{
+        ctxt->exception = vec;
+        ctxt->error_code = error;
+        ctxt->error_code_valid = valid;
+        ctxt->restart = false;
+}
+
+static void emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
+{
+        emulate_exception(ctxt, GP_VECTOR, err, true);
+}
+
+static void emulate_pf(struct x86_emulate_ctxt *ctxt, unsigned long addr,
+                       int err)
+{
+        ctxt->cr2 = addr;
+        emulate_exception(ctxt, PF_VECTOR, err, true);
+}
+
+static void emulate_ud(struct x86_emulate_ctxt *ctxt)
+{
+        emulate_exception(ctxt, UD_VECTOR, 0, false);
+}
+
+static void emulate_ts(struct x86_emulate_ctxt *ctxt, int err)
+{
+        emulate_exception(ctxt, TS_VECTOR, err, true);
+}
+
 static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
                               struct x86_emulate_ops *ops,
                               unsigned long eip, u8 *dest)
@@ -1285,7 +1316,7 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
                 rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
                                         ctxt->vcpu);
                 if (rc == X86EMUL_PROPAGATE_FAULT)
-                        kvm_inject_page_fault(ctxt->vcpu, addr, err);
+                        emulate_pf(ctxt, addr, err);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
                 mc->end += n;
@@ -1366,13 +1397,13 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
         get_descriptor_table_ptr(ctxt, ops, selector, &dt);
 
         if (dt.size < index * 8 + 7) {
-                kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+                emulate_gp(ctxt, selector & 0xfffc);
                 return X86EMUL_PROPAGATE_FAULT;
         }
         addr = dt.address + index * 8;
         ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,  &err);
         if (ret == X86EMUL_PROPAGATE_FAULT)
-                kvm_inject_page_fault(ctxt->vcpu, addr, err);
+                emulate_pf(ctxt, addr, err);
 
        return ret;
 }
@@ -1391,14 +1422,14 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
         get_descriptor_table_ptr(ctxt, ops, selector, &dt);
 
         if (dt.size < index * 8 + 7) {
-                kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+                emulate_gp(ctxt, selector & 0xfffc);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
         addr = dt.address + index * 8;
         ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
         if (ret == X86EMUL_PROPAGATE_FAULT)
-                kvm_inject_page_fault(ctxt->vcpu, addr, err);
+                emulate_pf(ctxt, addr, err);
 
         return ret;
 }
@@ -1517,7 +1548,7 @@ load:
         ops->set_cached_descriptor(&seg_desc, seg, ctxt->vcpu);
         return X86EMUL_CONTINUE;
 exception:
-        kvm_queue_exception_e(ctxt->vcpu, err_vec, err_code);
+        emulate_exception(ctxt, err_vec, err_code, true);
         return X86EMUL_PROPAGATE_FAULT;
 }
 
@@ -1578,7 +1609,7 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
                 break;
         case X86EMUL_MODE_VM86:
                 if (iopl < 3) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
                 change_mask |= EFLG_IF;
@@ -1829,7 +1860,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
                                         &err,
                                         ctxt->vcpu);
                 if (rc == X86EMUL_PROPAGATE_FAULT)
-                        kvm_inject_page_fault(ctxt->vcpu,
+                        emulate_pf(ctxt,
                                               (unsigned long)c->dst.ptr, err);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
@@ -1883,7 +1914,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         /* syscall is not available in real mode */
         if (ctxt->mode == X86EMUL_MODE_REAL ||
             ctxt->mode == X86EMUL_MODE_VM86) {
-                kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                emulate_ud(ctxt);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
@@ -1937,7 +1968,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 
         /* inject #GP if in real mode */
         if (ctxt->mode == X86EMUL_MODE_REAL) {
-                kvm_inject_gp(ctxt->vcpu, 0);
+                emulate_gp(ctxt, 0);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
@@ -1945,7 +1976,7 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         * Therefore, we inject an #UD.
         */
         if (ctxt->mode == X86EMUL_MODE_PROT64) {
-                kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                emulate_ud(ctxt);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
@@ -1955,13 +1986,13 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         switch (ctxt->mode) {
         case X86EMUL_MODE_PROT32:
                 if ((msr_data & 0xfffc) == 0x0) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
                 break;
         case X86EMUL_MODE_PROT64:
                 if (msr_data == 0x0) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
                 break;
@@ -2004,7 +2035,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         /* inject #GP if in real mode or Virtual 8086 mode */
         if (ctxt->mode == X86EMUL_MODE_REAL ||
             ctxt->mode == X86EMUL_MODE_VM86) {
-                kvm_inject_gp(ctxt->vcpu, 0);
+                emulate_gp(ctxt, 0);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
@@ -2022,7 +2053,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         case X86EMUL_MODE_PROT32:
                 cs_sel = (u16)(msr_data + 16);
                 if ((msr_data & 0xfffc) == 0x0) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
                 ss_sel = (u16)(msr_data + 24);
@@ -2030,7 +2061,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         case X86EMUL_MODE_PROT64:
                 cs_sel = (u16)(msr_data + 32);
                 if (msr_data == 0x0) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
                 ss_sel = cs_sel + 8;
@@ -2192,7 +2223,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                             &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+                emulate_pf(ctxt, old_tss_base, err);
                 return ret;
         }
 
@@ -2202,7 +2233,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                              &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+                emulate_pf(ctxt, old_tss_base, err);
                 return ret;
         }
 
@@ -2210,7 +2241,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                             &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                emulate_pf(ctxt, new_tss_base, err);
                 return ret;
         }
 
@@ -2223,7 +2254,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                                      ctxt->vcpu, &err);
                 if (ret == X86EMUL_PROPAGATE_FAULT) {
                         /* FIXME: need to provide precise fault address */
-                        kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                        emulate_pf(ctxt, new_tss_base, err);
                         return ret;
                 }
         }
@@ -2266,7 +2297,7 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
         int ret;
 
         if (ops->set_cr(3, tss->cr3, ctxt->vcpu)) {
-                kvm_inject_gp(ctxt->vcpu, 0);
+                emulate_gp(ctxt, 0);
                 return X86EMUL_PROPAGATE_FAULT;
         }
         c->eip = tss->eip;
@@ -2334,7 +2365,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                             &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+                emulate_pf(ctxt, old_tss_base, err);
                 return ret;
         }
 
@@ -2344,7 +2375,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                              &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+                emulate_pf(ctxt, old_tss_base, err);
                 return ret;
         }
 
@@ -2352,7 +2383,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                             &err);
         if (ret == X86EMUL_PROPAGATE_FAULT) {
                 /* FIXME: need to provide precise fault address */
-                kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                emulate_pf(ctxt, new_tss_base, err);
                 return ret;
         }
 
@@ -2365,7 +2396,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                                      ctxt->vcpu, &err);
                 if (ret == X86EMUL_PROPAGATE_FAULT) {
                         /* FIXME: need to provide precise fault address */
-                        kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+                        emulate_pf(ctxt, new_tss_base, err);
                         return ret;
                 }
         }
@@ -2399,7 +2430,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
         if (reason != TASK_SWITCH_IRET) {
                 if ((tss_selector & 3) > next_tss_desc.dpl ||
                     ops->cpl(ctxt->vcpu) > next_tss_desc.dpl) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         return X86EMUL_PROPAGATE_FAULT;
                 }
         }
@@ -2408,8 +2439,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
         if (!next_tss_desc.p ||
             ((desc_limit < 0x67 && (next_tss_desc.type & 8)) ||
              desc_limit < 0x2b)) {
-                kvm_queue_exception_e(ctxt->vcpu, TS_VECTOR,
-                                      tss_selector & 0xfffc);
+                emulate_ts(ctxt, tss_selector & 0xfffc);
                 return X86EMUL_PROPAGATE_FAULT;
         }
 
@@ -2505,19 +2535,19 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
         ctxt->decode.mem_read.pos = 0;
 
         if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
-                kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                emulate_ud(ctxt);
                 goto done;
         }
 
         /* LOCK prefix is allowed only with some instructions */
         if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
-                kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                emulate_ud(ctxt);
                 goto done;
         }
 
         /* Privileged instruction can be executed only in CPL=0 */
         if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
-                kvm_inject_gp(ctxt->vcpu, 0);
+                emulate_gp(ctxt, 0);
                 goto done;
         }
 
@@ -2679,7 +2709,7 @@ special_insn:
                 c->dst.bytes = min(c->dst.bytes, 4u);
                 if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
                                           c->dst.bytes)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 if (!pio_in_emulated(ctxt, ops, c->dst.bytes,
@@ -2691,7 +2721,7 @@ special_insn:
                 c->src.bytes = min(c->src.bytes, 4u);
                 if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
                                           c->src.bytes)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 ops->pio_out_emulated(c->src.bytes, c->regs[VCPU_REGS_RDX],
@@ -2754,7 +2784,7 @@ special_insn:
                 goto mov;
         case 0x8c:  /* mov r/m, sreg */
                 if (c->modrm_reg > VCPU_SREG_GS) {
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 }
                 c->dst.val = ops->get_segment_selector(c->modrm_reg, ctxt->vcpu);
@@ -2769,7 +2799,7 @@ special_insn:
 
                 if (c->modrm_reg == VCPU_SREG_CS ||
                     c->modrm_reg > VCPU_SREG_GS) {
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 }
 
@@ -2895,7 +2925,7 @@ special_insn:
         do_io_in:
                 c->dst.bytes = min(c->dst.bytes, 4u);
                 if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 if (!pio_in_emulated(ctxt, ops, c->dst.bytes, c->src.val,
@@ -2908,7 +2938,7 @@ special_insn:
         do_io_out:
                 c->dst.bytes = min(c->dst.bytes, 4u);
                 if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 ops->pio_out_emulated(c->dst.bytes, c->src.val, &c->dst.val, 1,
@@ -2933,7 +2963,7 @@ special_insn:
                 break;
         case 0xfa: /* cli */
                 if (emulator_bad_iopl(ctxt, ops))
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                 else {
                         ctxt->eflags &= ~X86_EFLAGS_IF;
                         c->dst.type = OP_NONE;  /* Disable writeback. */
@@ -2941,7 +2971,7 @@ special_insn:
                 break;
         case 0xfb: /* sti */
                 if (emulator_bad_iopl(ctxt, ops))
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                 else {
                         ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
                         ctxt->eflags |= X86_EFLAGS_IF;
@@ -3069,7 +3099,7 @@ twobyte_insn:
                         c->dst.type = OP_NONE;
                         break;
                 case 5: /* not defined */
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 case 7: /* invlpg*/
                         emulate_invlpg(ctxt->vcpu, c->modrm_ea);
@@ -3102,7 +3132,7 @@ twobyte_insn:
                 case 1:
                 case 5 ... 7:
                 case 9 ... 15:
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 }
                 c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
@@ -3111,7 +3141,7 @@ twobyte_insn:
         case 0x21: /* mov from dr to reg */
                 if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
                     (c->modrm_reg == 4 || c->modrm_reg == 5)) {
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 }
                 ops->get_dr(c->modrm_reg, &c->regs[c->modrm_rm], ctxt->vcpu);
@@ -3119,7 +3149,7 @@ twobyte_insn:
                 break;
         case 0x22: /* mov reg, cr */
                 if (ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 c->dst.type = OP_NONE;
@@ -3127,7 +3157,7 @@ twobyte_insn:
         case 0x23: /* mov from reg to dr */
                 if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
                     (c->modrm_reg == 4 || c->modrm_reg == 5)) {
-                        kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+                        emulate_ud(ctxt);
                         goto done;
                 }
 
@@ -3135,7 +3165,7 @@ twobyte_insn:
                                 ((ctxt->mode == X86EMUL_MODE_PROT64) ?
                                  ~0ULL : ~0U), ctxt->vcpu) < 0) {
                         /* #UD condition is already handled by the code above */
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
 
@@ -3146,7 +3176,7 @@ twobyte_insn:
                 msr_data = (u32)c->regs[VCPU_REGS_RAX]
                         | ((u64)c->regs[VCPU_REGS_RDX] << 32);
                 if (ops->set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 }
                 rc = X86EMUL_CONTINUE;
@@ -3155,7 +3185,7 @@ twobyte_insn:
         case 0x32:
                 /* rdmsr */
                 if (ops->get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
-                        kvm_inject_gp(ctxt->vcpu, 0);
+                        emulate_gp(ctxt, 0);
                         goto done;
                 } else {
                         c->regs[VCPU_REGS_RAX] = (u32)msr_data;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 91bfe7771f50..63c87adcec48 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3852,6 +3852,17 @@ static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
                 kvm_x86_ops->set_interrupt_shadow(vcpu, mask);
 }
 
+static void inject_emulated_exception(struct kvm_vcpu *vcpu)
+{
+        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
+        if (ctxt->exception == PF_VECTOR)
+                kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
+        else if (ctxt->error_code_valid)
+                kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
+        else
+                kvm_queue_exception(vcpu, ctxt->exception);
+}
+
 int emulate_instruction(struct kvm_vcpu *vcpu,
                         unsigned long cr2,
                         u16 error_code,
@@ -3886,6 +3897,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
                 memset(c, 0, sizeof(struct decode_cache));
                 memcpy(c->regs, vcpu->arch.regs, sizeof c->regs);
                 vcpu->arch.emulate_ctxt.interruptibility = 0;
+                vcpu->arch.emulate_ctxt.exception = -1;
 
                 r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
                 trace_kvm_emulate_insn_start(vcpu);
@@ -3958,6 +3970,11 @@ restart:
         memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
         kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
 
+        if (vcpu->arch.emulate_ctxt.exception >= 0) {
+                inject_emulated_exception(vcpu);
+                return EMULATE_DONE;
+        }
+
         if (vcpu->arch.pio.count) {
                 if (!vcpu->arch.pio.in)
                         vcpu->arch.pio.count = 0;
@@ -3970,9 +3987,6 @@ restart:
                 return EMULATE_DO_MMIO;
         }
 
-        if (vcpu->arch.exception.pending)
-                vcpu->arch.emulate_ctxt.restart = false;
-
         if (vcpu->arch.emulate_ctxt.restart)
                 goto restart;