KVM: x86: Refactor guest debug IOCTL handling

Much of so far vendor-specific code for setting up guest debug can
actually be handled by the generic code. This also fixes a minor deficit
in the SVM part /wrt processing KVM_GUESTDBG_ENABLE.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 26 insertions, 38 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 295c7c4d9c90..e7f870832603 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -475,8 +475,8 @@ struct kvm_x86_ops {
         void (*vcpu_load)(struct kvm_vcpu *vcpu, int cpu);
         void (*vcpu_put)(struct kvm_vcpu *vcpu);
 
-        int (*set_guest_debug)(struct kvm_vcpu *vcpu,
-                               struct kvm_guest_debug *dbg);
+        void (*set_guest_debug)(struct kvm_vcpu *vcpu,
+                                struct kvm_guest_debug *dbg);
         int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
         int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
         u64 (*get_segment_base)(struct kvm_vcpu *vcpu, int seg);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 02a4269be645..279a2ae21b4f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1065,26 +1065,16 @@ static void update_db_intercept(struct kvm_vcpu *vcpu)
                 vcpu->guest_debug = 0;
 }
 
-static int svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
+static void svm_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
 {
-        int old_debug = vcpu->guest_debug;
         struct vcpu_svm *svm = to_svm(vcpu);
 
-        vcpu->guest_debug = dbg->control;
-
-        update_db_intercept(vcpu);
-
         if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
                 svm->vmcb->save.dr7 = dbg->arch.debugreg[7];
         else
                 svm->vmcb->save.dr7 = vcpu->arch.dr7;
 
-        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
-                svm->vmcb->save.rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
-        else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
-                svm->vmcb->save.rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
-
-        return 0;
+        update_db_intercept(vcpu);
 }
 
 static void load_host_msrs(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 97f4265cda38..70020e505c22 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1096,30 +1096,14 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
         }
 }
 
-static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
+static void set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg)
 {
-        int old_debug = vcpu->guest_debug;
-        unsigned long flags;
-
-        vcpu->guest_debug = dbg->control;
-        if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
-                vcpu->guest_debug = 0;
-
         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);
-        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);
-
         update_exception_bitmap(vcpu);
-
-        return 0;
 }
 
 static __init int cpu_has_kvm_support(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f44d565cc9b..a06f88e66c89 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4472,12 +4472,19 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
                                         struct kvm_guest_debug *dbg)
 {
-        int i, r;
+        unsigned long rflags;
+        int old_debug;
+        int i;
 
         vcpu_load(vcpu);
 
-        if ((dbg->control & (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) ==
-            (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) {
+        old_debug = vcpu->guest_debug;
+
+        vcpu->guest_debug = dbg->control;
+        if (!(vcpu->guest_debug & KVM_GUESTDBG_ENABLE))
+                vcpu->guest_debug = 0;
+
+        if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
                 for (i = 0; i < KVM_NR_DB_REGS; ++i)
                         vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
                 vcpu->arch.switch_db_regs =
@@ -4488,16 +4495,23 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
                 vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK);
         }
 
-        r = kvm_x86_ops->set_guest_debug(vcpu, dbg);
+        rflags = kvm_x86_ops->get_rflags(vcpu);
+        if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+                rflags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
+        else if (old_debug & KVM_GUESTDBG_SINGLESTEP)
+                rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
+        kvm_x86_ops->set_rflags(vcpu, rflags);
 
-        if (dbg->control & KVM_GUESTDBG_INJECT_DB)
+        kvm_x86_ops->set_guest_debug(vcpu, dbg);
+
+        if (vcpu->guest_debug & KVM_GUESTDBG_INJECT_DB)
                 kvm_queue_exception(vcpu, DB_VECTOR);
-        else if (dbg->control & KVM_GUESTDBG_INJECT_BP)
+        else if (vcpu->guest_debug & KVM_GUESTDBG_INJECT_BP)
                 kvm_queue_exception(vcpu, BP_VECTOR);
 
         vcpu_put(vcpu);
 
-        return r;
+        return 0;
 }
 
 /*