1 files changed, 98 insertions, 16 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c776868ffe41..0989776ee7b0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2311,7 +2311,6 @@ 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);
@@ -2577,7 +2576,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
         u32 intr_info, ex_no, error_code;
-        unsigned long cr2, rip;
+        unsigned long cr2, rip, dr6;
         u32 vect_info;
         enum emulation_result er;
 
@@ -2637,14 +2636,28 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         }
 
         ex_no = intr_info & INTR_INFO_VECTOR_MASK;
-        if (ex_no == DB_VECTOR || ex_no == BP_VECTOR) {
+        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;
                 kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
                 kvm_run->debug.arch.exception = ex_no;
-        } else {
+                break;
+        default:
                 kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
                 kvm_run->ex.exception = ex_no;
                 kvm_run->ex.error_code = error_code;
+                break;
         }
         return 0;
 }
@@ -2784,21 +2797,44 @@ 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;
@@ -2806,7 +2842,38 @@ 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;
@@ -2957,7 +3024,18 @@ 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)
@@ -3342,6 +3420,8 @@ 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;"
@@ -3436,6 +3516,8 @@ 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);