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, 12 insertions, 6 deletions

diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index a3fa537e717a..bc6c28d04263 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -226,33 +226,39 @@ static inline void vringh_notify(struct vringh *vrh)
 		vrh->notify(vrh);
 }
 
+static inline bool vringh_is_little_endian(const struct vringh *vrh)
+{
+	return vrh->little_endian ||
+		virtio_legacy_is_little_endian();
+}
+
 static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val)
 {
-	return __virtio16_to_cpu(vrh->little_endian, val);
+	return __virtio16_to_cpu(vringh_is_little_endian(vrh), val);
 }
 
 static inline __virtio16 cpu_to_vringh16(const struct vringh *vrh, u16 val)
 {
-	return __cpu_to_virtio16(vrh->little_endian, val);
+	return __cpu_to_virtio16(vringh_is_little_endian(vrh), val);
 }
 
 static inline u32 vringh32_to_cpu(const struct vringh *vrh, __virtio32 val)
 {
-	return __virtio32_to_cpu(vrh->little_endian, val);
+	return __virtio32_to_cpu(vringh_is_little_endian(vrh), val);
 }
 
 static inline __virtio32 cpu_to_vringh32(const struct vringh *vrh, u32 val)
 {
-	return __cpu_to_virtio32(vrh->little_endian, val);
+	return __cpu_to_virtio32(vringh_is_little_endian(vrh), val);
 }
 
 static inline u64 vringh64_to_cpu(const struct vringh *vrh, __virtio64 val)
 {
-	return __virtio64_to_cpu(vrh->little_endian, val);
+	return __virtio64_to_cpu(vringh_is_little_endian(vrh), val);
 }
 
 static inline __virtio64 cpu_to_vringh64(const struct vringh *vrh, u64 val)
 {
-	return __cpu_to_virtio64(vrh->little_endian, val);
+	return __cpu_to_virtio64(vringh_is_little_endian(vrh), val);
 }
 #endif /* _LINUX_VRINGH_H */