When adding cross-endian support, we introduced the TARGET_IS_BIENDIAN macro
and the virtio_access_is_big_endian() helper to have a branchless fast path
in the virtio memory accessors for targets that don't switch endian.
This was considered as a strong requirement at the time.
Now we have added a runtime check for virtio 1.0, which ruins the benefit
of the virtio_access_is_big_endian() helper for always little-endian targets.
With this patch, fixed little-endian targets stop checking for virtio 1.0,
since the result is little-endian in all cases. The helper also gets renamed
so it is clear it is optimized for fast paths.
Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com>
---
include/hw/virtio/virtio-access.h | 43 ++++++++++++++++++++-----------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/include/hw/virtio/virtio-access.h
b/include/hw/virtio/virtio-access.h
index ba1530619939..ff013519b9dc 100644
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -17,12 +17,15 @@
#include "hw/virtio/virtio.h"
#include "exec/address-spaces.h"
-static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
+static inline bool virtio_is_big_endian_fast(VirtIODevice *vdev)
{
+#if defined(TARGET_IS_BIENDIAN) || defined(TARGET_WORDS_BIGENDIAN)
if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
/* Devices conforming to VIRTIO 1.0 or later are always LE. */
return false;
}
+#endif
+
#if defined(TARGET_IS_BIENDIAN)
return virtio_is_big_endian(vdev);
#elif defined(TARGET_WORDS_BIGENDIAN)
@@ -34,7 +37,7 @@ static inline bool virtio_access_is_big_endian(VirtIODevice
*vdev)
static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return lduw_be_phys(&address_space_memory, pa);
}
return lduw_le_phys(&address_space_memory, pa);
@@ -42,7 +45,7 @@ static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev,
hwaddr pa)
static inline uint32_t virtio_ldl_phys(VirtIODevice *vdev, hwaddr pa)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return ldl_be_phys(&address_space_memory, pa);
}
return ldl_le_phys(&address_space_memory, pa);
@@ -50,7 +53,7 @@ static inline uint32_t virtio_ldl_phys(VirtIODevice *vdev,
hwaddr pa)
static inline uint64_t virtio_ldq_phys(VirtIODevice *vdev, hwaddr pa)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return ldq_be_phys(&address_space_memory, pa);
}
return ldq_le_phys(&address_space_memory, pa);
@@ -59,7 +62,7 @@ static inline uint64_t virtio_ldq_phys(VirtIODevice *vdev,
hwaddr pa)
static inline void virtio_stw_phys(VirtIODevice *vdev, hwaddr pa,
uint16_t value)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
stw_be_phys(&address_space_memory, pa, value);
} else {
stw_le_phys(&address_space_memory, pa, value);
@@ -69,7 +72,7 @@ static inline void virtio_stw_phys(VirtIODevice *vdev, hwaddr
pa,
static inline void virtio_stl_phys(VirtIODevice *vdev, hwaddr pa,
uint32_t value)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
stl_be_phys(&address_space_memory, pa, value);
} else {
stl_le_phys(&address_space_memory, pa, value);
@@ -78,7 +81,7 @@ static inline void virtio_stl_phys(VirtIODevice *vdev, hwaddr
pa,
static inline void virtio_stw_p(VirtIODevice *vdev, void *ptr, uint16_t v)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
stw_be_p(ptr, v);
} else {
stw_le_p(ptr, v);
@@ -87,7 +90,7 @@ static inline void virtio_stw_p(VirtIODevice *vdev, void
*ptr, uint16_t v)
static inline void virtio_stl_p(VirtIODevice *vdev, void *ptr, uint32_t v)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
stl_be_p(ptr, v);
} else {
stl_le_p(ptr, v);
@@ -96,7 +99,7 @@ static inline void virtio_stl_p(VirtIODevice *vdev, void
*ptr, uint32_t v)
static inline void virtio_stq_p(VirtIODevice *vdev, void *ptr, uint64_t v)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
stq_be_p(ptr, v);
} else {
stq_le_p(ptr, v);
@@ -105,7 +108,7 @@ static inline void virtio_stq_p(VirtIODevice *vdev, void
*ptr, uint64_t v)
static inline int virtio_lduw_p(VirtIODevice *vdev, const void *ptr)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return lduw_be_p(ptr);
} else {
return lduw_le_p(ptr);
@@ -114,7 +117,7 @@ static inline int virtio_lduw_p(VirtIODevice *vdev, const
void *ptr)
static inline int virtio_ldl_p(VirtIODevice *vdev, const void *ptr)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return ldl_be_p(ptr);
} else {
return ldl_le_p(ptr);
@@ -123,7 +126,7 @@ static inline int virtio_ldl_p(VirtIODevice *vdev, const
void *ptr)
static inline uint64_t virtio_ldq_p(VirtIODevice *vdev, const void *ptr)
{
- if (virtio_access_is_big_endian(vdev)) {
+ if (virtio_is_big_endian_fast(vdev)) {
return ldq_be_p(ptr);
} else {
return ldq_le_p(ptr);
@@ -133,18 +136,18 @@ static inline uint64_t virtio_ldq_p(VirtIODevice *vdev,
const void *ptr)
static inline bool virtio_needs_swap(VirtIODevice *vdev)
{
#ifdef HOST_WORDS_BIGENDIAN
- return virtio_access_is_big_endian(vdev) ? false : true;
+ return virtio_is_big_endian_fast(vdev) ? false : true;
#else
- return virtio_access_is_big_endian(vdev) ? true : false;
+ return virtio_is_big_endian_fast(vdev) ? true : false;
#endif
}
static inline uint16_t virtio_tswap16(VirtIODevice *vdev, uint16_t s)
{
#ifdef HOST_WORDS_BIGENDIAN
- return virtio_access_is_big_endian(vdev) ? s : bswap16(s);
+ return virtio_is_big_endian_fast(vdev) ? s : bswap16(s);
#else
- return virtio_access_is_big_endian(vdev) ? bswap16(s) : s;
+ return virtio_is_big_endian_fast(vdev) ? bswap16(s) : s;
#endif
}
@@ -156,9 +159,9 @@ static inline void virtio_tswap16s(VirtIODevice *vdev,
uint16_t *s)
static inline uint32_t virtio_tswap32(VirtIODevice *vdev, uint32_t s)
{
#ifdef HOST_WORDS_BIGENDIAN
- return virtio_access_is_big_endian(vdev) ? s : bswap32(s);
+ return virtio_is_big_endian_fast(vdev) ? s : bswap32(s);
#else
- return virtio_access_is_big_endian(vdev) ? bswap32(s) : s;
+ return virtio_is_big_endian_fast(vdev) ? bswap32(s) : s;
#endif
}
@@ -170,9 +173,9 @@ static inline void virtio_tswap32s(VirtIODevice *vdev,
uint32_t *s)
static inline uint64_t virtio_tswap64(VirtIODevice *vdev, uint64_t s)
{
#ifdef HOST_WORDS_BIGENDIAN
- return virtio_access_is_big_endian(vdev) ? s : bswap64(s);
+ return virtio_is_big_endian_fast(vdev) ? s : bswap64(s);
#else
- return virtio_access_is_big_endian(vdev) ? bswap64(s) : s;
+ return virtio_is_big_endian_fast(vdev) ? bswap64(s) : s;
#endif
}
