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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>
This commit is contained in:
Paolo Bonzini 2020-12-14 07:49:54 -05:00
parent 29d6ca4199
commit 996ff5429e
3 changed files with 20 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
arch/x86/kvm/svm/svm.c
View File

@ -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)

17
arch/x86/kvm/vmx/vmx.c
View File

@ -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)

19
arch/x86/kvm/x86.c
View File

@ -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;