From: Adrian Bunk <bunk@kernel.org>
Date: Tue, 5 Aug 2008 22:36:09 +0000 (+0300)
Subject: KVM: fix userspace ABI breakage
X-Git-Tag: v2.6.27-rc5~38^2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1327138e294ffda120a50c8f31d792addb196c79;p=linux-2.6

KVM: fix userspace ABI breakage

The following part of commit 9ef621d3be56e1188300476a8102ff54f7b6793f
(KVM: Support mixed endian machines) changed on the size of a struct
that is exported to userspace:

include/linux/kvm.h:

@@ -318,14 +318,14 @@ struct kvm_trace_rec {
 	__u32 vcpu_id;
 	union {
 		struct {
-			__u32 cycle_lo, cycle_hi;
+			__u64 cycle_u64;
 			__u32 extra_u32[KVM_TRC_EXTRA_MAX];
 		} cycle;
 		struct {
 			__u32 extra_u32[KVM_TRC_EXTRA_MAX];
 		} nocycle;
 	} u;
-};
+} __attribute__((packed));

Packing a struct was the correct idea, but it packed the wrong struct.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 69511f74f9..70a30651cd 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -320,12 +320,12 @@ struct kvm_trace_rec {
 		struct {
 			__u64 cycle_u64;
 			__u32 extra_u32[KVM_TRC_EXTRA_MAX];
-		} cycle;
+		} __attribute__((packed)) cycle;
 		struct {
 			__u32 extra_u32[KVM_TRC_EXTRA_MAX];
 		} nocycle;
 	} u;
-} __attribute__((packed));
+};
 
 #define KVMIO 0xAE