diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-02-26 12:28:40 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-03-09 13:15:10 -0500 |
| commit | 18d609bb0b8c6823a750b32106be5685ca3daff7 (patch) | |
| tree | 1029cb3396c12588e839d4be9afc750a713019f4 | |
| parent | d017f850a3b6f84e6d847c6cbb01eaf6ce61f4f6 (diff) | |
KVM: x86: fix root cause for missed hardware breakpoints
[ Upstream commit 70e4da7a8ff62f2775337b705f45c804bb450454 ]
Commit 172b2386ed16 ("KVM: x86: fix missed hardware breakpoints",
2016-02-10) worked around a case where the debug registers are not loaded
correctly on preemption and on the first entry to KVM_RUN.
However, Xiao Guangrong pointed out that the root cause must be that
KVM_DEBUGREG_BP_ENABLED is not being set correctly. This can indeed
happen due to the lazy debug exit mechanism, which does not call
kvm_update_dr7. Fix it by replacing the existing loop (more or less
equivalent to kvm_update_dr0123) with calls to all the kvm_update_dr*
functions.
Cc: stable@vger.kernel.org # 4.1+
Fixes: 172b2386ed16a9143d9a456aae5ec87275c61489
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0dbf28a6d83d..42f1575ab58d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2968,7 +2968,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) accumulate_steal_time(vcpu); kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu); - vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD; } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) @@ -6372,12 +6371,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) * KVM_DEBUGREG_WONT_EXIT again. */ if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) { - int i; - WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP); kvm_x86_ops->sync_dirty_debug_regs(vcpu); - for (i = 0; i < KVM_NR_DB_REGS; i++) - vcpu->arch.eff_db[i] = vcpu->arch.db[i]; + kvm_update_dr0123(vcpu); + kvm_update_dr6(vcpu); + kvm_update_dr7(vcpu); + vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD; } /* |