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-rw-r--r--Documentation/virtual/kvm/api.txt15
1 files changed, 12 insertions, 3 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index f670e4b9e7f3..57d3ee9e4bde 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2901,14 +2901,19 @@ userspace buffer and its length:
struct kvm_s390_irq_state {
__u64 buf;
- __u32 flags;
+ __u32 flags; /* will stay unused for compatibility reasons */
__u32 len;
- __u32 reserved[4];
+ __u32 reserved[4]; /* will stay unused for compatibility reasons */
};
Userspace passes in the above struct and for each pending interrupt a
struct kvm_s390_irq is copied to the provided buffer.
+The structure contains a flags and a reserved field for future extensions. As
+the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and
+reserved, these fields can not be used in the future without breaking
+compatibility.
+
If -ENOBUFS is returned the buffer provided was too small and userspace
may retry with a bigger buffer.
@@ -2932,10 +2937,14 @@ containing a struct kvm_s390_irq_state:
struct kvm_s390_irq_state {
__u64 buf;
+ __u32 flags; /* will stay unused for compatibility reasons */
__u32 len;
- __u32 pad;
+ __u32 reserved[4]; /* will stay unused for compatibility reasons */
};
+The restrictions for flags and reserved apply as well.
+(see KVM_S390_GET_IRQ_STATE)
+
The userspace memory referenced by buf contains a struct kvm_s390_irq
for each interrupt to be injected into the guest.
If one of the interrupts could not be injected for some reason the