KVM: x86: move kvm_inject_gp up from kvm_set_dr to callers

Push the injection of #GP up to the callers, so that they can just use
kvm_complete_insn_gp. __kvm_set_dr is pretty much what the callers can use
together with kvm_complete_insn_gp, so rename it to kvm_set_dr and drop
the old kvm_set_dr wrapper.

This also allows nested VMX code, which really wanted to use __kvm_set_dr,
to use the right function.

While at it, remove the kvm_require_dr() check from the SVM interception.
The APM states:

  All normal exception checks take precedence over the SVM intercepts.

which includes the CR4.DE=1 #UD.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ef2f2b0..42d4710 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2617,6 +2617,7 @@ static int dr_interception(struct vcpu_svm *svm)
 {
        int reg, dr;
        unsigned long val;
+       int err = 0;
 
        if (svm->vcpu.guest_debug == 0) {
                /*
@@ -2634,20 +2635,16 @@ static int dr_interception(struct vcpu_svm *svm)
 
        reg = svm->vmcb->control.exit_info_1 & SVM_EXITINFO_REG_MASK;
        dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
-
-       if (dr >= 16) { /* mov to DRn */
-               if (!kvm_require_dr(&svm->vcpu, dr - 16))
-                       return 1;
+       if (dr >= 16) { /* mov to DRn  */
+               dr -= 16;
                val = kvm_register_read(&svm->vcpu, reg);
-               kvm_set_dr(&svm->vcpu, dr - 16, val);
+               err = kvm_set_dr(&svm->vcpu, dr, val);
        } else {
-               if (!kvm_require_dr(&svm->vcpu, dr))
-                       return 1;
                kvm_get_dr(&svm->vcpu, dr, &val);
                kvm_register_write(&svm->vcpu, reg, val);
        }
 
-       return kvm_skip_emulated_instruction(&svm->vcpu);
+       return kvm_complete_insn_gp(&svm->vcpu, err);
 }
 
 static int cr8_write_interception(struct vcpu_svm *svm)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 049fbbd..1389887 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5095,6 +5095,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 {
        unsigned long exit_qualification;
        int dr, dr7, reg;
+       int err = 1;
 
        exit_qualification = vmx_get_exit_qual(vcpu);
        dr = exit_qualification & DEBUG_REG_ACCESS_NUM;
@@ -5103,9 +5104,9 @@ static int handle_dr(struct kvm_vcpu *vcpu)
        if (!kvm_require_dr(vcpu, dr))
                return 1;
 
-       /* Do not handle if the CPL > 0, will trigger GP on re-entry */
-       if (!kvm_require_cpl(vcpu, 0))
-               return 1;
+       if (kvm_x86_ops.get_cpl(vcpu) > 0)
+               goto out;
+
        dr7 = vmcs_readl(GUEST_DR7);
        if (dr7 & DR7_GD) {
                /*
@@ -5144,11 +5145,13 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 
                kvm_get_dr(vcpu, dr, &val);
                kvm_register_write(vcpu, reg, val);
-       } else
-               if (kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg)))
-                       return 1;
+               err = 0;
+       } else {
+               err = kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg));
+       }
 
-       return kvm_skip_emulated_instruction(vcpu);
+out:
+       return kvm_complete_insn_gp(vcpu, err);
 }
 
 static void vmx_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dcb6742..baa90ae 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1143,7 +1143,7 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu)
        return fixed;
 }
 
-static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
+int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 {
        size_t size = ARRAY_SIZE(vcpu->arch.db);
 
@@ -1156,13 +1156,13 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
        case 4:
        case 6:
                if (!kvm_dr6_valid(val))
-                       return -1; /* #GP */
+                       return 1; /* #GP */
                vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
                break;
        case 5:
        default: /* 7 */
                if (!kvm_dr7_valid(val))
-                       return -1; /* #GP */
+                       return 1; /* #GP */
                vcpu->arch.dr7 = (val & DR7_VOLATILE) | DR7_FIXED_1;
                kvm_update_dr7(vcpu);
                break;
@@ -1170,15 +1170,6 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 
        return 0;
 }
-
-int kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
-{
-       if (__kvm_set_dr(vcpu, dr, val)) {
-               kvm_inject_gp(vcpu, 0);
-               return 1;
-       }
-       return 0;
-}
 EXPORT_SYMBOL_GPL(kvm_set_dr);
 
 void kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
@@ -6619,7 +6610,7 @@ static int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
                           unsigned long value)
 {
 
-       return __kvm_set_dr(emul_to_vcpu(ctxt), dr, value);
+       return kvm_set_dr(emul_to_vcpu(ctxt), dr, value);
 }
 
 static u64 mk_cr_64(u64 curr_cr, u32 new_val)
@@ -8664,7 +8655,7 @@ static void enter_smm(struct kvm_vcpu *vcpu)
        dt.address = dt.size = 0;
        static_call(kvm_x86_set_idt)(vcpu, &dt);
 
-       __kvm_set_dr(vcpu, 7, DR7_FIXED_1);
+       kvm_set_dr(vcpu, 7, DR7_FIXED_1);
 
        cs.selector = (vcpu->arch.smbase >> 4) & 0xffff;
        cs.base = vcpu->arch.smbase;