Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio/vhost cross endian support from Michael Tsirkin:
 "I have just queued some more bugfix patches today but none fix
  regressions and none are related to these ones, so it looks like a
  good time for a merge for -rc1.

  The motivation for this is support for legacy BE guests on the new LE
  hosts.  There are two redeeming properties that made me merge this:

   - It's a trivial amount of code: since we wrap host/guest accesses
     anyway, almost all of it is well hidden from drivers.

   - Sane platforms would never set flags like VHOST_CROSS_ENDIAN_LEGACY,
     and when it's clear, there's zero overhead (as some point it was
     tested by compiling with and without the patches, got the same
     stripped binary).

  Maybe we could create a Kconfig symbol to enforce the second point:
  prevent people from enabling it eg on x86.  I will look into this"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio-pci: alloc only resources actually used.
  macvtap/tun: cross-endian support for little-endian hosts
  vhost: cross-endian support for legacy devices
  virtio: add explicit big-endian support to memory accessors
  vhost: introduce vhost_is_little_endian() helper
  vringh: introduce vringh_is_little_endian() helper
  macvtap: introduce macvtap_is_little_endian() helper
  tun: add tun_is_little_endian() helper
  virtio: introduce virtio_is_little_endian() helper

1 files changed, 14 insertions, 10 deletions

diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h
index 51865d05b267..ce63a2c3a612 100644
--- a/include/linux/virtio_byteorder.h
+++ b/include/linux/virtio_byteorder.h
@@ -3,17 +3,21 @@
 #include <linux/types.h>
 #include <uapi/linux/virtio_types.h>
 
-/*
- * Low-level memory accessors for handling virtio in modern little endian and in
- * compatibility native endian format.
- */
+static inline bool virtio_legacy_is_little_endian(void)
+{
+#ifdef __LITTLE_ENDIAN
+	return true;
+#else
+	return false;
+#endif
+}
 
 static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
 {
 	if (little_endian)
 		return le16_to_cpu((__force __le16)val);
 	else
-		return (__force u16)val;
+		return be16_to_cpu((__force __be16)val);
 }
 
 static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
@@ -21,7 +25,7 @@ static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
 	if (little_endian)
 		return (__force __virtio16)cpu_to_le16(val);
 	else
-		return (__force __virtio16)val;
+		return (__force __virtio16)cpu_to_be16(val);
 }
 
 static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
@@ -29,7 +33,7 @@ static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
 	if (little_endian)
 		return le32_to_cpu((__force __le32)val);
 	else
-		return (__force u32)val;
+		return be32_to_cpu((__force __be32)val);
 }
 
 static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
@@ -37,7 +41,7 @@ static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
 	if (little_endian)
 		return (__force __virtio32)cpu_to_le32(val);
 	else
-		return (__force __virtio32)val;
+		return (__force __virtio32)cpu_to_be32(val);
 }
 
 static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
@@ -45,7 +49,7 @@ static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
 	if (little_endian)
 		return le64_to_cpu((__force __le64)val);
 	else
-		return (__force u64)val;
+		return be64_to_cpu((__force __be64)val);
 }
 
 static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
@@ -53,7 +57,7 @@ static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
 	if (little_endian)
 		return (__force __virtio64)cpu_to_le64(val);
 	else
-		return (__force __virtio64)val;
+		return (__force __virtio64)cpu_to_be64(val);
 }
 
 #endif /* _LINUX_VIRTIO_BYTEORDER */