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KVM: x86: DR0-DR3 are not clear on reset

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DR0-DR3 are not cleared as they should during reset and when they are set from
userspace.  It appears to be caused by c77fb5fe6f ("KVM: x86: Allow the guest
to run with dirty debug registers").

Force their reload on these situations.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-4-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nadav Amit 2015-04-02 03:10:37 +03:00 committed by Paolo Bonzini
parent 58d269d8cc
commit ae561edeb4
2 changed files with 15 additions and 0 deletions
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1
arch/x86/include/asm/kvm_host.h
View File

@ -340,6 +340,7 @@ struct kvm_pmu {
enum {
KVM_DEBUGREG_BP_ENABLED = 1,
KVM_DEBUGREG_WONT_EXIT = 2,
KVM_DEBUGREG_RELOAD = 4,
};
struct kvm_vcpu_arch {

14
arch/x86/kvm/x86.c
View File

@ -801,6 +801,17 @@ unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_get_cr8);
static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
{
int i;
if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
for (i = 0; i < KVM_NR_DB_REGS; i++)
vcpu->arch.eff_db[i] = vcpu->arch.db[i];
vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD;
}
}
static void kvm_update_dr6(struct kvm_vcpu *vcpu)
{
if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
@ -3150,6 +3161,7 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
return -EINVAL;
memcpy(vcpu->arch.db, dbgregs->db, sizeof(vcpu->arch.db));
kvm_update_dr0123(vcpu);
vcpu->arch.dr6 = dbgregs->dr6;
kvm_update_dr6(vcpu);
vcpu->arch.dr7 = dbgregs->dr7;
@ -6323,6 +6335,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
set_debugreg(vcpu->arch.eff_db[2], 2);
set_debugreg(vcpu->arch.eff_db[3], 3);
set_debugreg(vcpu->arch.dr6, 6);
vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
}
trace_kvm_entry(vcpu->vcpu_id);
@ -7104,6 +7117,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu)
kvm_clear_exception_queue(vcpu);
memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
kvm_update_dr0123(vcpu);
vcpu->arch.dr6 = DR6_INIT;
kvm_update_dr6(vcpu);
vcpu->arch.dr7 = DR7_FIXED_1;