From: Greg Kurz <groug@kaod.org>
To: "Philippe Mathieu-Daudé" <philmd@linaro.org>
Cc: qemu-devel@nongnu.org, "Thomas Huth" <thuth@redhat.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Kevin Wolf" <kwolf@redhat.com>,
qemu-block@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Jason Wang" <jasowang@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Christian Schoenebeck" <qemu_oss@crudebyte.com>,
"Hanna Reitz" <hreitz@redhat.com>
Subject: Re: [RFC PATCH-for-8.0 07/10] hw/virtio: Directly access cached VirtIODevice::access_is_big_endian
Date: Tue, 13 Dec 2022 11:50:19 +0100 [thread overview]
Message-ID: <20221213115019.4adfc326@bahia> (raw)
In-Reply-To: <20221212230517.28872-8-philmd@linaro.org>
On Tue, 13 Dec 2022 00:05:14 +0100
Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
> Since the device endianness doesn't change at runtime,
> use the cached value instead of evaluating it on each call.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> include/hw/virtio/virtio-access.h | 44 +++++++++++++++----------------
> 1 file changed, 22 insertions(+), 22 deletions(-)
>
> diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h
> index 07aae69042..985f39fe16 100644
> --- a/include/hw/virtio/virtio-access.h
> +++ b/include/hw/virtio/virtio-access.h
> @@ -43,7 +43,7 @@ static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa)
> {
> AddressSpace *dma_as = vdev->dma_as;
>
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
For x86, virtio_access_is_big_endian() expands to :
static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
{
return false;
}
When I added these memory accessors, there was a strong requirement from MST
that x86 shouldn't have to pay for an out-of-line check when it is known that
everything is always little endian. Not sure exactly what you're trying to
achieve with VirtIODevice::access_is_big_endian but this shouldn't mess with
this fast path.
> return lduw_be_phys(dma_as, pa);
> }
> return lduw_le_phys(dma_as, pa);
> @@ -53,7 +53,7 @@ static inline uint32_t virtio_ldl_phys(VirtIODevice *vdev, hwaddr pa)
> {
> AddressSpace *dma_as = vdev->dma_as;
>
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> return ldl_be_phys(dma_as, pa);
> }
> return ldl_le_phys(dma_as, pa);
> @@ -63,7 +63,7 @@ static inline uint64_t virtio_ldq_phys(VirtIODevice *vdev, hwaddr pa)
> {
> AddressSpace *dma_as = vdev->dma_as;
>
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> return ldq_be_phys(dma_as, pa);
> }
> return ldq_le_phys(dma_as, pa);
> @@ -74,7 +74,7 @@ static inline void virtio_stw_phys(VirtIODevice *vdev, hwaddr pa,
> {
> AddressSpace *dma_as = vdev->dma_as;
>
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> stw_be_phys(dma_as, pa, value);
> } else {
> stw_le_phys(dma_as, pa, value);
> @@ -86,7 +86,7 @@ static inline void virtio_stl_phys(VirtIODevice *vdev, hwaddr pa,
> {
> AddressSpace *dma_as = vdev->dma_as;
>
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> stl_be_phys(dma_as, pa, value);
> } else {
> stl_le_phys(dma_as, pa, value);
> @@ -95,7 +95,7 @@ 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 (vdev->access_is_big_endian) {
> stw_be_p(ptr, v);
> } else {
> stw_le_p(ptr, v);
> @@ -104,7 +104,7 @@ 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 (vdev->access_is_big_endian) {
> stl_be_p(ptr, v);
> } else {
> stl_le_p(ptr, v);
> @@ -113,7 +113,7 @@ 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 (vdev->access_is_big_endian) {
> stq_be_p(ptr, v);
> } else {
> stq_le_p(ptr, v);
> @@ -122,7 +122,7 @@ 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 (vdev->access_is_big_endian) {
> return lduw_be_p(ptr);
> } else {
> return lduw_le_p(ptr);
> @@ -131,7 +131,7 @@ 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 (vdev->access_is_big_endian) {
> return ldl_be_p(ptr);
> } else {
> return ldl_le_p(ptr);
> @@ -140,7 +140,7 @@ 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 (vdev->access_is_big_endian) {
> return ldq_be_p(ptr);
> } else {
> return ldq_le_p(ptr);
> @@ -150,9 +150,9 @@ static inline uint64_t virtio_ldq_p(VirtIODevice *vdev, const void *ptr)
> static inline uint16_t virtio_tswap16(VirtIODevice *vdev, uint16_t s)
> {
> #if HOST_BIG_ENDIAN
> - return virtio_access_is_big_endian(vdev) ? s : bswap16(s);
> + return vdev->access_is_big_endian ? s : bswap16(s);
> #else
> - return virtio_access_is_big_endian(vdev) ? bswap16(s) : s;
> + return vdev->access_is_big_endian ? bswap16(s) : s;
> #endif
> }
>
> @@ -160,7 +160,7 @@ static inline uint16_t virtio_lduw_phys_cached(VirtIODevice *vdev,
> MemoryRegionCache *cache,
> hwaddr pa)
> {
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> return lduw_be_phys_cached(cache, pa);
> }
> return lduw_le_phys_cached(cache, pa);
> @@ -170,7 +170,7 @@ static inline uint32_t virtio_ldl_phys_cached(VirtIODevice *vdev,
> MemoryRegionCache *cache,
> hwaddr pa)
> {
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> return ldl_be_phys_cached(cache, pa);
> }
> return ldl_le_phys_cached(cache, pa);
> @@ -180,7 +180,7 @@ static inline uint64_t virtio_ldq_phys_cached(VirtIODevice *vdev,
> MemoryRegionCache *cache,
> hwaddr pa)
> {
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> return ldq_be_phys_cached(cache, pa);
> }
> return ldq_le_phys_cached(cache, pa);
> @@ -190,7 +190,7 @@ static inline void virtio_stw_phys_cached(VirtIODevice *vdev,
> MemoryRegionCache *cache,
> hwaddr pa, uint16_t value)
> {
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> stw_be_phys_cached(cache, pa, value);
> } else {
> stw_le_phys_cached(cache, pa, value);
> @@ -201,7 +201,7 @@ static inline void virtio_stl_phys_cached(VirtIODevice *vdev,
> MemoryRegionCache *cache,
> hwaddr pa, uint32_t value)
> {
> - if (virtio_access_is_big_endian(vdev)) {
> + if (vdev->access_is_big_endian) {
> stl_be_phys_cached(cache, pa, value);
> } else {
> stl_le_phys_cached(cache, pa, value);
> @@ -216,9 +216,9 @@ static inline void virtio_tswap16s(VirtIODevice *vdev, uint16_t *s)
> static inline uint32_t virtio_tswap32(VirtIODevice *vdev, uint32_t s)
> {
> #if HOST_BIG_ENDIAN
> - return virtio_access_is_big_endian(vdev) ? s : bswap32(s);
> + return vdev->access_is_big_endian ? s : bswap32(s);
> #else
> - return virtio_access_is_big_endian(vdev) ? bswap32(s) : s;
> + return vdev->access_is_big_endian ? bswap32(s) : s;
> #endif
> }
>
> @@ -230,9 +230,9 @@ static inline void virtio_tswap32s(VirtIODevice *vdev, uint32_t *s)
> static inline uint64_t virtio_tswap64(VirtIODevice *vdev, uint64_t s)
> {
> #if HOST_BIG_ENDIAN
> - return virtio_access_is_big_endian(vdev) ? s : bswap64(s);
> + return vdev->access_is_big_endian ? s : bswap64(s);
> #else
> - return virtio_access_is_big_endian(vdev) ? bswap64(s) : s;
> + return vdev->access_is_big_endian ? bswap64(s) : s;
> #endif
> }
>
next prev parent reply other threads:[~2022-12-13 10:51 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-12 23:05 [RFC PATCH-for-8.0 00/10] hw/virtio: Build most objects as target independent units Philippe Mathieu-Daudé
2022-12-12 23:05 ` [PATCH-for-8.0 01/10] hw/virtio: Add missing "hw/core/cpu.h" include Philippe Mathieu-Daudé
2022-12-12 23:05 ` [PATCH-for-8.0 02/10] hw/virtio: Rename virtio_ss[] -> specific_virtio_ss[] Philippe Mathieu-Daudé
2022-12-12 23:05 ` [PATCH-for-8.0 03/10] hw/virtio: Constify qmp_virtio_feature_map_t[] Philippe Mathieu-Daudé
2022-12-13 0:02 ` Richard Henderson
2022-12-13 7:35 ` Philippe Mathieu-Daudé
2022-12-12 23:05 ` [PATCH-for-8.0 04/10] hw/virtio: Extract config read/write accessors to virtio-config.c Philippe Mathieu-Daudé
2022-12-12 23:05 ` [PATCH-for-8.0 05/10] hw/virtio: Extract QMP related code virtio-qmp.c Philippe Mathieu-Daudé
2022-12-12 23:05 ` [RFC PATCH-for-8.0 06/10] hw/virtio: Cache access_is_big_endian value in VirtIODevice state Philippe Mathieu-Daudé
2022-12-13 0:14 ` Richard Henderson
2022-12-13 7:30 ` Philippe Mathieu-Daudé
2022-12-13 8:03 ` Thomas Huth
2022-12-13 8:32 ` Philippe Mathieu-Daudé
2022-12-13 8:47 ` Thomas Huth
2022-12-13 8:22 ` Philippe Mathieu-Daudé
2022-12-13 15:41 ` Richard Henderson
2022-12-12 23:05 ` [RFC PATCH-for-8.0 07/10] hw/virtio: Directly access cached VirtIODevice::access_is_big_endian Philippe Mathieu-Daudé
2022-12-13 10:50 ` Greg Kurz [this message]
2022-12-12 23:05 ` [PATCH-for-8.0 08/10] hw/virtio: Un-inline virtio_access_is_big_endian() Philippe Mathieu-Daudé
2022-12-12 23:05 ` [RFC PATCH-for-8.0 09/10] hw/virtio: Extract vhost_user_ram_slots_max() to vhost-user-target.c Philippe Mathieu-Daudé
2025-04-10 12:14 ` Philippe Mathieu-Daudé
2025-04-10 14:36 ` Pierrick Bouvier
2025-04-10 17:21 ` Philippe Mathieu-Daudé
2025-04-10 17:29 ` Pierrick Bouvier
2025-04-11 10:15 ` Philippe Mathieu-Daudé
2022-12-12 23:05 ` [RFC PATCH-for-8.0 10/10] hw/virtio: Make most of virtio devices target-independent Philippe Mathieu-Daudé
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