KVM: x86: Add KVM_GET/SET_VCPU_EVENTS

This new IOCTL exports all yet user-invisible states related to
exceptions, interrupts, and NMIs. Together with appropriate user space
changes, this fixes sporadic problems of vmsave/restore, live migration
and system reset.

[avi: future-proof abi by adding a flags field]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 36594ba57723..e1a114161027 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -653,6 +653,55 @@ struct kvm_clock_data {
         __u32 pad[9];
 };
 
+4.29 KVM_GET_VCPU_EVENTS
+
+Capability: KVM_CAP_VCPU_EVENTS
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_vcpu_event (out)
+Returns: 0 on success, -1 on error
+
+Gets currently pending exceptions, interrupts, and NMIs as well as related
+states of the vcpu.
+
+struct kvm_vcpu_events {
+        struct {
+                __u8 injected;
+                __u8 nr;
+                __u8 has_error_code;
+                __u8 pad;
+                __u32 error_code;
+        } exception;
+        struct {
+                __u8 injected;
+                __u8 nr;
+                __u8 soft;
+                __u8 pad;
+        } interrupt;
+        struct {
+                __u8 injected;
+                __u8 pending;
+                __u8 masked;
+                __u8 pad;
+        } nmi;
+        __u32 sipi_vector;
+        __u32 flags;   /* must be zero */
+};
+
+4.30 KVM_SET_VCPU_EVENTS
+
+Capability: KVM_CAP_VCPU_EVENTS
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_vcpu_event (in)
+Returns: 0 on success, -1 on error
+
+Set pending exceptions, interrupts, and NMIs as well as related states of the
+vcpu.
+
+See KVM_GET_VCPU_EVENTS for the data structure.
+
+
 5. The kvm_run structure
 
 Application code obtains a pointer to the kvm_run structure by