KVM: x86: add SYNC_REGS_SIZE_BYTES #define.

Replace hardcoded padding size value for struct kvm_sync_regs
with #define SYNC_REGS_SIZE_BYTES.

Also update the value specified in api.txt from outdated hardcoded
value to SYNC_REGS_SIZE_BYTES.

Signed-off-by: Ken Hofsass <hofsass@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index db992e0..55867a2 100644 (file)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3905,7 +3905,7 @@ in userspace.
        __u64 kvm_dirty_regs;
        union {
                struct kvm_sync_regs regs;
-               char padding[1024];
+               char padding[SYNC_REGS_SIZE_BYTES];
        } s;
 
 If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2d2d926..088c2c9 100644 (file)
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -396,6 +396,10 @@ struct kvm_run {
                char padding[256];
        };
 
+       /* 2048 is the size of the char array used to bound/pad the size
+        * of the union that holds sync regs.
+        */
+       #define SYNC_REGS_SIZE_BYTES 2048
        /*
         * shared registers between kvm and userspace.
         * kvm_valid_regs specifies the register classes set by the host
@@ -407,7 +411,7 @@ struct kvm_run {
        __u64 kvm_dirty_regs;
        union {
                struct kvm_sync_regs regs;
-               char padding[2048];
+               char padding[SYNC_REGS_SIZE_BYTES];
        } s;
 };