On 26/02/2016 12:28, Nadav Amit wrote: > Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> wrote: > >> On 02/19/2016 06:56 PM, Paolo Bonzini wrote: >>> Sometimes when setting a breakpoint a process doesn't stop on it. >>> This is because the debug registers are not loaded correctly on >>> VCPU load. >>> >>> >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 4244c2baf57d..f4891f2ece23 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -2752,6 +2752,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) >>> } >>> >>> kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu); >>> + vcpu->arch.switch_db_regs |= KVM_DEBUGREG_RELOAD; >> >> Er, i do not understand how it works. The BP is enabled in this test case so >> the debug registers are always reloaded before entering guest as >> KVM_DEBUGREG_BP_ENABLED bit is always set on switch_db_regs. What did i miss? > > Note that KVM_DEBUGREG_BP_ENABLED does not have to be set, since > kvm_update_dr7() is not called once the guest has KVM_DEBUGREG_WONT_EXIT. Looks like our emails crossed; could you review the patch I have just sent? Paolo -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html