Gleb Natapov wrote:
>> +
>> +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;
>> +}
>> +
> This makes double fault (8) benign exception. Surely not what you
> want.
double fault fall into neither of above class per SDM. But it should be
checked earlier than generating DB fault. See new updated.
>> + /* to check exception */
>> + prev_nr = vcpu->arch.exception.nr;
>> + class2 = exception_class(nr);
>> + class1 = exception_class(prev_nr);
>> + if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
>> + || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
>> + /* generate double fault per SDM Table 5-5 */
>> + printk(KERN_DEBUG "kvm: double fault 0x%x on 0x%x\n",
>> + prev_nr, nr); + vcpu->arch.exception.pending =
>> true;
>> + vcpu->arch.exception.has_error_code = 1;
>> + vcpu->arch.exception.nr = DF_VECTOR;
>> + vcpu->arch.exception.error_code = 0;
>> + if (prev_nr == DF_VECTOR) {
>> + /* triple fault -> shutdown */
>> + set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests); +
>> }
>> + } else
>> + printk(KERN_ERR "Exception 0x%x on 0x%x happens serially\n",
>> + prev_nr, nr); +}
> When two exceptions happens serially is is better to replace pending
> exception with a new one. This way the first exception (that is lost)
> will be regenerated when instruction will be re-executed.
Do you want it to be covered for now? For exception, it is easy but for IRQ, it
needs to be pushed back.
Thx, eddie
Move Double-Fault generation logic out of page fault
exception generating function to cover more generic case.
Signed-off-by: Eddie Dong <[email protected]>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ab1fdac..d0e75a2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -162,12 +162,60 @@ 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) {
+ 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 */
+ printk(KERN_DEBUG "kvm: double fault 0x%x on 0x%x\n",
+ prev_nr, nr);
+ 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
+ printk(KERN_ERR "Exception 0x%x on 0x%x happens serially\n",
+ prev_nr, nr);
+}
+
void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
- WARN_ON(vcpu->arch.exception.pending);
- vcpu->arch.exception.pending = true;
- vcpu->arch.exception.has_error_code = false;
- vcpu->arch.exception.nr = nr;
+ kvm_multiple_exception(vcpu, nr, false, 0);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception);
@@ -176,18 +224,6 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned
long addr,
{
++vcpu->stat.pf_guest;
- if (vcpu->arch.exception.pending) {
- if (vcpu->arch.exception.nr == PF_VECTOR) {
- printk(KERN_DEBUG "kvm: inject_page_fault:"
- " double fault 0x%lx\n", addr);
- vcpu->arch.exception.nr = DF_VECTOR;
- vcpu->arch.exception.error_code = 0;
- } else if (vcpu->arch.exception.nr == DF_VECTOR) {
- /* triple fault -> shutdown */
- set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
- }
- return;
- }
vcpu->arch.cr2 = addr;
kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
}
@@ -200,11 +236,7 @@ EXPORT_SYMBOL_GPL(kvm_inject_nmi);
void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
- WARN_ON(vcpu->arch.exception.pending);
- vcpu->arch.exception.pending = true;
- vcpu->arch.exception.has_error_code = true;
- vcpu->arch.exception.nr = nr;
- vcpu->arch.exception.error_code = error_code;
+ kvm_multiple_exception(vcpu, nr, true, error_code);
}
EXPORT_SYMBOL_GPL(kvm_queue_exception_e);
irq2.patch
Description: irq2.patch
