KVM: Allow internal errors reported to userspace to carry extra data
Usually userspace will freeze the guest so we can inspect it, but some
internal state is not available. Add extra data to internal error
reporting so we can expose it to the debugger. Extra data is specific
to the suberror.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a902479..4c3e5b2 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2800,6 +2800,7 @@
case EMULATE_FAIL:
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+ vcpu->run->internal.ndata = 0;
return 0;
default:
BUG();
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c9cc959..c0e66dd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3352,6 +3352,7 @@
kvm_report_emulation_failure(vcpu, "emulation failure");
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
+ vcpu->run->internal.ndata = 0;
ret = 0;
goto out;
}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index ca62b8e..172639e 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -251,6 +251,9 @@
} dcr;
struct {
__u32 suberror;
+ /* Available with KVM_CAP_INTERNAL_ERROR_DATA: */
+ __u32 ndata;
+ __u64 data[16];
} internal;
/* Fix the size of the union. */
char padding[256];
@@ -484,6 +487,7 @@
#define KVM_CAP_XEN_HVM 38
#endif
#define KVM_CAP_ADJUST_CLOCK 39
+#define KVM_CAP_INTERNAL_ERROR_DATA 40
#ifdef KVM_CAP_IRQ_ROUTING
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bd44fb4..f92ba13 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1653,6 +1653,7 @@
#ifdef CONFIG_KVM_APIC_ARCHITECTURE
case KVM_CAP_SET_BOOT_CPU_ID:
#endif
+ case KVM_CAP_INTERNAL_ERROR_DATA:
return 1;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
case KVM_CAP_IRQ_ROUTING: