On Thu, Nov 12, 2009 at 02:21:24PM +0200, Gleb Natapov wrote: > On Wed, Nov 11, 2009 at 05:29:47PM -0200, Marcelo Tosatti wrote: > > I suppose a complete fix would be to follow the "Conditions for > > Generating a Double Fault" with support for handling exceptions > > serially. > > > > But this works for me. > > > I prefer proper solution. Like one attached (this is combination of ths > patch by Eddie Dong and my fix): > > Move Double-Fault generation logic out of page fault > exception generating function to cover more generic case. > > Signed-off-by: Eddie Dong <[email protected]> > Signed-off-by: Gleb Natapov <[email protected]>
Nice. Tested-by: Marcelo Tosatti <[email protected]> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 76c8375..88c4490 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -248,12 +248,61 @@ void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data) > } > EXPORT_SYMBOL_GPL(kvm_set_apic_base); > > +#define EXCPT_BENIGN 0 > +#define EXCPT_CONTRIBUTORY 1 > +#define EXCPT_PF 2 > + > +static int exception_class(int vector) > +{ > + if (vector == 14) > + return EXCPT_PF; > + else if (vector == 0 || (vector >= 10 && vector <= 13)) > + return EXCPT_CONTRIBUTORY; > + else > + return EXCPT_BENIGN; > +} > + > +static void kvm_multiple_exception(struct kvm_vcpu *vcpu, > + unsigned nr, bool has_error, u32 error_code) > +{ > + u32 prev_nr; > + int class1, class2; > + > + if (!vcpu->arch.exception.pending) { > + queue: > + vcpu->arch.exception.pending = true; > + vcpu->arch.exception.has_error_code = has_error; > + vcpu->arch.exception.nr = nr; > + vcpu->arch.exception.error_code = error_code; > + return; > + } > + > + /* to check exception */ > + prev_nr = vcpu->arch.exception.nr; > + if (prev_nr == DF_VECTOR) { > + /* triple fault -> shutdown */ > + set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests); > + return; > + } > + class1 = exception_class(prev_nr); > + class2 = exception_class(nr); > + if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY) > + || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) { > + /* generate double fault per SDM Table 5-5 */ > + vcpu->arch.exception.pending = true; > + vcpu->arch.exception.has_error_code = true; > + vcpu->arch.exception.nr = DF_VECTOR; > + vcpu->arch.exception.error_code = 0; > + } else > + /* replace previous exception with a new one in a hope > + that instruction re-execution will regenerate lost > + exception */ Out of curiosity, why not an exception queue? > + goto queue; This goto seems unnecessary. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
