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Subject[PATCH 01/40] KVM: x86: make double/triple fault promotion generic to all exceptions
Date
From: Eddie Dong <eddie.dong@intel.com>

Move Double-Fault generation logic out of page fault
exception generating function to cover more generic case.

Signed-off-by: Eddie Dong <eddie.dong@intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
arch/x86/kvm/x86.c | 89 +++++++++++++++++++++++++++++++++++----------------
1 files changed, 61 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ddcad4..b503614 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -257,12 +257,68 @@ 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)
+{
+ switch (vector) {
+ case PF_VECTOR:
+ return EXCPT_PF;
+ case DE_VECTOR:
+ case TS_VECTOR:
+ case NP_VECTOR:
+ case SS_VECTOR:
+ case GP_VECTOR:
+ return EXCPT_CONTRIBUTORY;
+ default:
+ break;
+ }
+ 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 */
+ goto queue;
+}
+
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);

@@ -270,25 +326,6 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
u32 error_code)
{
++vcpu->stat.pf_guest;
-
- if (vcpu->arch.exception.pending) {
- switch(vcpu->arch.exception.nr) {
- case DF_VECTOR:
- /* triple fault -> shutdown */
- set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
- return;
- case PF_VECTOR:
- vcpu->arch.exception.nr = DF_VECTOR;
- vcpu->arch.exception.error_code = 0;
- return;
- default:
- /* replace previous exception with a new one in a hope
- that instruction re-execution will regenerate lost
- exception */
- vcpu->arch.exception.pending = false;
- break;
- }
- }
vcpu->arch.cr2 = addr;
kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
}
@@ -301,11 +338,7 @@ 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);

--
1.6.5.3


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