[PATCH] KVM: s390: add explicit padding to struct kvm_s390_keyop

From: Arnd Bergmann

Date: Fri Feb 06 2026 - 04:18:00 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

The newly added structure causes a warning about implied padding:

./usr/include/linux/kvm.h:1247:1: error: padding struct size to alignment boundary with 6 bytes [-Werror=padded]

The padding can lead to leaking kernel data and ABI incompatibilies
when used on x86. Neither of these is a problem in this specific
patch, but it's best to avoid it and use explicit padding fields
in general.

Fixes: 0ee4ddc1647b ("KVM: s390: Storage key manipulation IOCTL")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
I have a long series to add annotations to all existing structures,
but that will take a while. For now, I'm sending fixes when new
instances show up in linux-next.
---
include/uapi/linux/kvm.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index a68b1741045c..1225fbd017e5 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1255,6 +1255,7 @@ struct kvm_s390_keyop {
__u64 guest_addr;
__u8 key;
__u8 operation;
+ __u8 pad[6];
};

/*
--
2.39.5