KVM: VMX: When emulating on invalid vmx state, don't return to userspace unnecessarily
[sfrench/cifs-2.6.git] / arch / x86 / kvm / vmx.c
index 7611af576829d820eba8de4a79d389e8baef7759..df454de8acfa2af8bf35fa96446ed300331cf6ba 100644 (file)
@@ -91,6 +91,7 @@ struct vcpu_vmx {
        } rmode;
        int vpid;
        bool emulation_required;
+       enum emulation_result invalid_state_emulation_result;
 
        /* Support for vnmi-less CPUs */
        int soft_vnmi_blocked;
@@ -189,21 +190,21 @@ static inline int is_page_fault(u32 intr_info)
 {
        return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                             INTR_INFO_VALID_MASK)) ==
-               (INTR_TYPE_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
+               (INTR_TYPE_HARD_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_no_device(u32 intr_info)
 {
        return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                             INTR_INFO_VALID_MASK)) ==
-               (INTR_TYPE_EXCEPTION | NM_VECTOR | INTR_INFO_VALID_MASK);
+               (INTR_TYPE_HARD_EXCEPTION | NM_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_invalid_opcode(u32 intr_info)
 {
        return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                             INTR_INFO_VALID_MASK)) ==
-               (INTR_TYPE_EXCEPTION | UD_VECTOR | INTR_INFO_VALID_MASK);
+               (INTR_TYPE_HARD_EXCEPTION | UD_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_external_interrupt(u32 intr_info)
@@ -480,8 +481,13 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
        eb = (1u << PF_VECTOR) | (1u << UD_VECTOR);
        if (!vcpu->fpu_active)
                eb |= 1u << NM_VECTOR;
-       if (vcpu->guest_debug.enabled)
-               eb |= 1u << DB_VECTOR;
+       if (vcpu->guest_debug & KVM_GUESTDBG_ENABLE) {
+               if (vcpu->guest_debug &
+                   (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
+                       eb |= 1u << DB_VECTOR;
+               if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
+                       eb |= 1u << BP_VECTOR;
+       }
        if (vcpu->arch.rmode.active)
                eb = ~0;
        if (vm_need_ept())
@@ -747,29 +753,33 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
                                bool has_error_code, u32 error_code)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
+       u32 intr_info = nr | INTR_INFO_VALID_MASK;
 
-       if (has_error_code)
+       if (has_error_code) {
                vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
+               intr_info |= INTR_INFO_DELIVER_CODE_MASK;
+       }
 
        if (vcpu->arch.rmode.active) {
                vmx->rmode.irq.pending = true;
                vmx->rmode.irq.vector = nr;
                vmx->rmode.irq.rip = kvm_rip_read(vcpu);
-               if (nr == BP_VECTOR)
+               if (nr == BP_VECTOR || nr == OF_VECTOR)
                        vmx->rmode.irq.rip++;
-               vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
-                            nr | INTR_TYPE_SOFT_INTR
-                            | (has_error_code ? INTR_INFO_DELIVER_CODE_MASK : 0)
-                            | INTR_INFO_VALID_MASK);
+               intr_info |= INTR_TYPE_SOFT_INTR;
+               vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
                vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
                kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
                return;
        }
 
-       vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
-                    nr | INTR_TYPE_EXCEPTION
-                    | (has_error_code ? INTR_INFO_DELIVER_CODE_MASK : 0)
-                    | INTR_INFO_VALID_MASK);
+       if (nr == BP_VECTOR || nr == OF_VECTOR) {
+               vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
+               intr_info |= INTR_TYPE_SOFT_EXCEPTION;
+       } else
+               intr_info |= INTR_TYPE_HARD_EXCEPTION;
+
+       vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
 }
 
 static bool vmx_exception_injected(struct kvm_vcpu *vcpu)
@@ -856,11 +866,8 @@ static u64 guest_read_tsc(void)
  * writes 'guest_tsc' into guest's timestamp counter "register"
  * guest_tsc = host_tsc + tsc_offset ==> tsc_offset = guest_tsc - host_tsc
  */
-static void guest_write_tsc(u64 guest_tsc)
+static void guest_write_tsc(u64 guest_tsc, u64 host_tsc)
 {
-       u64 host_tsc;
-
-       rdtscll(host_tsc);
        vmcs_write64(TSC_OFFSET, guest_tsc - host_tsc);
 }
 
@@ -925,6 +932,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
        struct kvm_msr_entry *msr;
+       u64 host_tsc;
        int ret = 0;
 
        switch (msr_index) {
@@ -950,7 +958,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
                vmcs_writel(GUEST_SYSENTER_ESP, data);
                break;
        case MSR_IA32_TIME_STAMP_COUNTER:
-               guest_write_tsc(data);
+               rdtscll(host_tsc);
+               guest_write_tsc(data, host_tsc);
                break;
        case MSR_P6_PERFCTR0:
        case MSR_P6_PERFCTR1:
@@ -999,40 +1008,28 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
        }
 }
 
-static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
+static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
 {
-       unsigned long dr7 = 0x400;
-       int old_singlestep;
-
-       old_singlestep = vcpu->guest_debug.singlestep;
-
-       vcpu->guest_debug.enabled = dbg->enabled;
-       if (vcpu->guest_debug.enabled) {
-               int i;
-
-               dr7 |= 0x200;  /* exact */
-               for (i = 0; i < 4; ++i) {
-                       if (!dbg->breakpoints[i].enabled)
-                               continue;
-                       vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address;
-                       dr7 |= 2 << (i*2);    /* global enable */
-                       dr7 |= 0 << (i*4+16); /* execution breakpoint */
-               }
+       int old_debug = vcpu->guest_debug;
+       unsigned long flags;
 
-               vcpu->guest_debug.singlestep = dbg->singlestep;
-       } else
-               vcpu->guest_debug.singlestep = 0;
+       vcpu->guest_debug = dbg->control;
+       if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
+               vcpu->guest_debug = 0;
 
-       if (old_singlestep && !vcpu->guest_debug.singlestep) {
-               unsigned long flags;
+       if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+               vmcs_writel(GUEST_DR7, dbg->arch.debugreg[7]);
+       else
+               vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
 
-               flags = vmcs_readl(GUEST_RFLAGS);
+       flags = vmcs_readl(GUEST_RFLAGS);
+       if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+               flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
+       else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
                flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
-               vmcs_writel(GUEST_RFLAGS, flags);
-       }
+       vmcs_writel(GUEST_RFLAGS, flags);
 
        update_exception_bitmap(vcpu);
-       vmcs_writel(GUEST_DR7, dr7);
 
        return 0;
 }
@@ -1653,7 +1650,7 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
        var->limit = vmcs_read32(sf->limit);
        var->selector = vmcs_read16(sf->selector);
        ar = vmcs_read32(sf->ar_bytes);
-       if (ar & AR_UNUSABLE_MASK)
+       if ((ar & AR_UNUSABLE_MASK) && !emulate_invalid_guest_state)
                ar = 0;
        var->type = ar & 15;
        var->s = (ar >> 4) & 1;
@@ -1788,14 +1785,16 @@ static bool code_segment_valid(struct kvm_vcpu *vcpu)
        vmx_get_segment(vcpu, &cs, VCPU_SREG_CS);
        cs_rpl = cs.selector & SELECTOR_RPL_MASK;
 
+       if (cs.unusable)
+               return false;
        if (~cs.type & (AR_TYPE_CODE_MASK|AR_TYPE_ACCESSES_MASK))
                return false;
        if (!cs.s)
                return false;
-       if (!(~cs.type & (AR_TYPE_CODE_MASK|AR_TYPE_WRITEABLE_MASK))) {
+       if (cs.type & AR_TYPE_WRITEABLE_MASK) {
                if (cs.dpl > cs_rpl)
                        return false;
-       } else if (cs.type & AR_TYPE_CODE_MASK) {
+       } else {
                if (cs.dpl != cs_rpl)
                        return false;
        }
@@ -1814,7 +1813,9 @@ static bool stack_segment_valid(struct kvm_vcpu *vcpu)
        vmx_get_segment(vcpu, &ss, VCPU_SREG_SS);
        ss_rpl = ss.selector & SELECTOR_RPL_MASK;
 
-       if ((ss.type != 3) || (ss.type != 7))
+       if (ss.unusable)
+               return true;
+       if (ss.type != 3 && ss.type != 7)
                return false;
        if (!ss.s)
                return false;
@@ -1834,6 +1835,8 @@ static bool data_segment_valid(struct kvm_vcpu *vcpu, int seg)
        vmx_get_segment(vcpu, &var, seg);
        rpl = var.selector & SELECTOR_RPL_MASK;
 
+       if (var.unusable)
+               return true;
        if (!var.s)
                return false;
        if (!var.present)
@@ -1855,9 +1858,11 @@ static bool tr_valid(struct kvm_vcpu *vcpu)
 
        vmx_get_segment(vcpu, &tr, VCPU_SREG_TR);
 
+       if (tr.unusable)
+               return false;
        if (tr.selector & SELECTOR_TI_MASK)     /* TI = 1 */
                return false;
-       if ((tr.type != 3) || (tr.type != 11)) /* TODO: Check if guest is in IA32e mode */
+       if (tr.type != 3 && tr.type != 11) /* TODO: Check if guest is in IA32e mode */
                return false;
        if (!tr.present)
                return false;
@@ -1871,6 +1876,8 @@ static bool ldtr_valid(struct kvm_vcpu *vcpu)
 
        vmx_get_segment(vcpu, &ldtr, VCPU_SREG_LDTR);
 
+       if (ldtr.unusable)
+               return true;
        if (ldtr.selector & SELECTOR_TI_MASK)   /* TI = 1 */
                return false;
        if (ldtr.type != 2)
@@ -2112,7 +2119,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 {
        u32 host_sysenter_cs, msr_low, msr_high;
        u32 junk;
-       u64 host_pat;
+       u64 host_pat, tsc_this, tsc_base;
        unsigned long a;
        struct descriptor_table dt;
        int i;
@@ -2240,6 +2247,12 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
        vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL);
        vmcs_writel(CR4_GUEST_HOST_MASK, KVM_GUEST_CR4_MASK);
 
+       tsc_base = vmx->vcpu.kvm->arch.vm_init_tsc;
+       rdtscll(tsc_this);
+       if (tsc_this < vmx->vcpu.kvm->arch.vm_init_tsc)
+               tsc_base = tsc_this;
+
+       guest_write_tsc(0, tsc_base);
 
        return 0;
 }
@@ -2319,7 +2332,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
                kvm_rip_write(vcpu, 0);
        kvm_register_write(vcpu, VCPU_REGS_RSP, 0);
 
-       /* todo: dr0 = dr1 = dr2 = dr3 = 0; dr6 = 0xffff0ff0 */
        vmcs_writel(GUEST_DR7, 0x400);
 
        vmcs_writel(GUEST_GDTR_BASE, 0);
@@ -2332,8 +2344,6 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
        vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, 0);
        vmcs_write32(GUEST_PENDING_DBG_EXCEPTIONS, 0);
 
-       guest_write_tsc(0);
-
        /* Special registers */
        vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
 
@@ -2486,6 +2496,11 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
 {
        vmx_update_window_states(vcpu);
 
+       if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+               vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+                               GUEST_INTR_STATE_STI |
+                               GUEST_INTR_STATE_MOV_SS);
+
        if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
                if (vcpu->arch.interrupt.pending) {
                        enable_nmi_window(vcpu);
@@ -2536,24 +2551,6 @@ static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr)
        return 0;
 }
 
-static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
-{
-       struct kvm_guest_debug *dbg = &vcpu->guest_debug;
-
-       set_debugreg(dbg->bp[0], 0);
-       set_debugreg(dbg->bp[1], 1);
-       set_debugreg(dbg->bp[2], 2);
-       set_debugreg(dbg->bp[3], 3);
-
-       if (dbg->singlestep) {
-               unsigned long flags;
-
-               flags = vmcs_readl(GUEST_RFLAGS);
-               flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
-               vmcs_writel(GUEST_RFLAGS, flags);
-       }
-}
-
 static int handle_rmode_exception(struct kvm_vcpu *vcpu,
                                  int vec, u32 err_code)
 {
@@ -2570,9 +2567,17 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
         *        the required debugging infrastructure rework.
         */
        switch (vec) {
-       case DE_VECTOR:
        case DB_VECTOR:
+               if (vcpu->guest_debug &
+                   (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
+                       return 0;
+               kvm_queue_exception(vcpu, vec);
+               return 1;
        case BP_VECTOR:
+               if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
+                       return 0;
+               /* fall through */
+       case DE_VECTOR:
        case OF_VECTOR:
        case BR_VECTOR:
        case UD_VECTOR:
@@ -2589,8 +2594,8 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
 static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
-       u32 intr_info, error_code;
-       unsigned long cr2, rip;
+       u32 intr_info, ex_no, error_code;
+       unsigned long cr2, rip, dr6;
        u32 vect_info;
        enum emulation_result er;
 
@@ -2649,14 +2654,30 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                return 1;
        }
 
-       if ((intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK)) ==
-           (INTR_TYPE_EXCEPTION | 1)) {
+       ex_no = intr_info & INTR_INFO_VECTOR_MASK;
+       switch (ex_no) {
+       case DB_VECTOR:
+               dr6 = vmcs_readl(EXIT_QUALIFICATION);
+               if (!(vcpu->guest_debug &
+                     (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {
+                       vcpu->arch.dr6 = dr6 | DR6_FIXED_1;
+                       kvm_queue_exception(vcpu, DB_VECTOR);
+                       return 1;
+               }
+               kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
+               kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
+               /* fall through */
+       case BP_VECTOR:
                kvm_run->exit_reason = KVM_EXIT_DEBUG;
-               return 0;
+               kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
+               kvm_run->debug.arch.exception = ex_no;
+               break;
+       default:
+               kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
+               kvm_run->ex.exception = ex_no;
+               kvm_run->ex.error_code = error_code;
+               break;
        }
-       kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
-       kvm_run->ex.exception = intr_info & INTR_INFO_VECTOR_MASK;
-       kvm_run->ex.error_code = error_code;
        return 0;
 }
 
@@ -2795,21 +2816,44 @@ static int handle_dr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        unsigned long val;
        int dr, reg;
 
-       /*
-        * FIXME: this code assumes the host is debugging the guest.
-        *        need to deal with guest debugging itself too.
-        */
+       dr = vmcs_readl(GUEST_DR7);
+       if (dr & DR7_GD) {
+               /*
+                * As the vm-exit takes precedence over the debug trap, we
+                * need to emulate the latter, either for the host or the
+                * guest debugging itself.
+                */
+               if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
+                       kvm_run->debug.arch.dr6 = vcpu->arch.dr6;
+                       kvm_run->debug.arch.dr7 = dr;
+                       kvm_run->debug.arch.pc =
+                               vmcs_readl(GUEST_CS_BASE) +
+                               vmcs_readl(GUEST_RIP);
+                       kvm_run->debug.arch.exception = DB_VECTOR;
+                       kvm_run->exit_reason = KVM_EXIT_DEBUG;
+                       return 0;
+               } else {
+                       vcpu->arch.dr7 &= ~DR7_GD;
+                       vcpu->arch.dr6 |= DR6_BD;
+                       vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+                       kvm_queue_exception(vcpu, DB_VECTOR);
+                       return 1;
+               }
+       }
+
        exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
-       dr = exit_qualification & 7;
-       reg = (exit_qualification >> 8) & 15;
-       if (exit_qualification & 16) {
-               /* mov from dr */
+       dr = exit_qualification & DEBUG_REG_ACCESS_NUM;
+       reg = DEBUG_REG_ACCESS_REG(exit_qualification);
+       if (exit_qualification & TYPE_MOV_FROM_DR) {
                switch (dr) {
+               case 0 ... 3:
+                       val = vcpu->arch.db[dr];
+                       break;
                case 6:
-                       val = 0xffff0ff0;
+                       val = vcpu->arch.dr6;
                        break;
                case 7:
-                       val = 0x400;
+                       val = vcpu->arch.dr7;
                        break;
                default:
                        val = 0;
@@ -2817,7 +2861,38 @@ static int handle_dr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                kvm_register_write(vcpu, reg, val);
                KVMTRACE_2D(DR_READ, vcpu, (u32)dr, (u32)val, handler);
        } else {
-               /* mov to dr */
+               val = vcpu->arch.regs[reg];
+               switch (dr) {
+               case 0 ... 3:
+                       vcpu->arch.db[dr] = val;
+                       if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+                               vcpu->arch.eff_db[dr] = val;
+                       break;
+               case 4 ... 5:
+                       if (vcpu->arch.cr4 & X86_CR4_DE)
+                               kvm_queue_exception(vcpu, UD_VECTOR);
+                       break;
+               case 6:
+                       if (val & 0xffffffff00000000ULL) {
+                               kvm_queue_exception(vcpu, GP_VECTOR);
+                               break;
+                       }
+                       vcpu->arch.dr6 = (val & DR6_VOLATILE) | DR6_FIXED_1;
+                       break;
+               case 7:
+                       if (val & 0xffffffff00000000ULL) {
+                               kvm_queue_exception(vcpu, GP_VECTOR);
+                               break;
+                       }
+                       vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
+                       if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
+                               vmcs_writel(GUEST_DR7, vcpu->arch.dr7);
+                               vcpu->arch.switch_db_regs =
+                                       (val & DR7_BP_EN_MASK);
+                       }
+                       break;
+               }
+               KVMTRACE_2D(DR_WRITE, vcpu, (u32)dr, (u32)val, handler);
        }
        skip_emulated_instruction(vcpu);
        return 1;
@@ -2968,7 +3043,18 @@ static int handle_task_switch(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        }
        tss_selector = exit_qualification;
 
-       return kvm_task_switch(vcpu, tss_selector, reason);
+       if (!kvm_task_switch(vcpu, tss_selector, reason))
+               return 0;
+
+       /* clear all local breakpoint enable flags */
+       vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~55);
+
+       /*
+        * TODO: What about debug traps on tss switch?
+        *       Are we supposed to inject them and update dr6?
+        */
+
+       return 1;
 }
 
 static int handle_ept_violation(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
@@ -3046,7 +3132,7 @@ static void handle_invalid_guest_state(struct kvm_vcpu *vcpu,
                                struct kvm_run *kvm_run)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
-       int err;
+       enum emulation_result err = EMULATE_DONE;
 
        preempt_enable();
        local_irq_enable();
@@ -3071,10 +3157,7 @@ static void handle_invalid_guest_state(struct kvm_vcpu *vcpu,
        local_irq_disable();
        preempt_disable();
 
-       /* Guest state should be valid now except if we need to
-        * emulate an MMIO */
-       if (guest_state_valid(vcpu))
-               vmx->emulation_required = 0;
+       vmx->invalid_state_emulation_result = err;
 }
 
 /*
@@ -3123,8 +3206,11 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 
        /* If we need to emulate an MMIO from handle_invalid_guest_state
         * we just return 0 */
-       if (vmx->emulation_required && emulate_invalid_guest_state)
-               return 0;
+       if (vmx->emulation_required && emulate_invalid_guest_state) {
+               if (guest_state_valid(vcpu))
+                       vmx->emulation_required = 0;
+               return vmx->invalid_state_emulation_result != EMULATE_DO_MMIO;
+       }
 
        /* Access CR3 don't cause VMExit in paging mode, so we need
         * to sync with guest real CR3. */
@@ -3238,7 +3324,8 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
                        vmx->vcpu.arch.nmi_injected = false;
        }
        kvm_clear_exception_queue(&vmx->vcpu);
-       if (idtv_info_valid && type == INTR_TYPE_EXCEPTION) {
+       if (idtv_info_valid && (type == INTR_TYPE_HARD_EXCEPTION ||
+                               type == INTR_TYPE_SOFT_EXCEPTION)) {
                if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
                        error = vmcs_read32(IDT_VECTORING_ERROR_CODE);
                        kvm_queue_exception_e(&vmx->vcpu, vector, error);
@@ -3259,6 +3346,11 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 
        vmx_update_window_states(vcpu);
 
+       if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+               vmcs_clear_bits(GUEST_INTERRUPTIBILITY_INFO,
+                               GUEST_INTR_STATE_STI |
+                               GUEST_INTR_STATE_MOV_SS);
+
        if (vcpu->arch.nmi_pending && !vcpu->arch.nmi_injected) {
                if (vcpu->arch.interrupt.pending) {
                        enable_nmi_window(vcpu);
@@ -3347,6 +3439,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         */
        vmcs_writel(HOST_CR0, read_cr0());
 
+       set_debugreg(vcpu->arch.dr6, 6);
+
        asm(
                /* Store host registers */
                "push %%"R"dx; push %%"R"bp;"
@@ -3441,6 +3535,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
        vcpu->arch.regs_dirty = 0;
 
+       get_debugreg(vcpu->arch.dr6, 6);
+
        vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
        if (vmx->rmode.irq.pending)
                fixup_rmode_irq(vmx);
@@ -3595,7 +3691,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
        .vcpu_put = vmx_vcpu_put,
 
        .set_guest_debug = set_guest_debug,
-       .guest_debug_pre = kvm_guest_debug_pre,
        .get_msr = vmx_get_msr,
        .set_msr = vmx_set_msr,
        .get_segment_base = vmx_get_segment_base,