Xiao Guangrong <[email protected]> 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. Nadav
