[PATCH v2 14/23] drm/xe/dma-buf: Use the SGT mapping type
Alistair Popple
apopple at nvidia.com
Wed Nov 4 22:40:49 PST 2026
From: Jason Gunthorpe <jgg at nvidia.com>
Like habana, xe wants to check pci_p2pdma_distance(), but unlike
habana, it can migrate to system memory and support non-p2p DMAs as well.
Add two exporter SGT mapping types, one that matches P2P and one that
matches all of the non-p2p. The pin and map code will force migrate if
the non-p2p one is matched.
Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
Signed-off-by: Alistair Popple <apopple at nvidia.com>
---
drivers/gpu/drm/xe/xe_dma_buf.c | 79 +++++++++++++++++++++--------------------
1 file changed, 41 insertions(+), 38 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
index 6a85b292dee7..f9bdfe7ee2c7 100644
--- a/drivers/gpu/drm/xe/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/xe_dma_buf.c
@@ -7,8 +7,7 @@
#include <kunit/test.h>
#include <linux/dma-buf.h>
-#include <linux/dynamic_debug.h>
-#include <linux/pci-p2pdma.h>
+#include <linux/dma-buf-mapping.h>
#include <drm/drm_device.h>
#include <drm/drm_prime.h>
@@ -23,33 +22,10 @@
MODULE_IMPORT_NS("DMA_BUF");
-#if defined(CONFIG_DYNAMIC_DEBUG) || \
- (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
-static void xe_ddebug_flip_bool(const struct _ddebug *desc, bool *flag)
-{
- *flag = true;
-}
-
-#define xe_dma_buf_p2p_debug_flip(flag) \
- _dynamic_func_call("xe dma-buf p2p debug", xe_ddebug_flip_bool, flag)
-#else
-#define xe_dma_buf_p2p_debug_flip(flag) do { } while (0)
-#endif
-
static int xe_dma_buf_attach(struct dma_buf *dmabuf,
struct dma_buf_attachment *attach)
{
struct drm_gem_object *obj = attach->dmabuf->priv;
- bool verbose_p2p_dist = drm_debug_enabled(DRM_UT_DRIVER);
-
- xe_dma_buf_p2p_debug_flip(&verbose_p2p_dist);
-
- if (attach->peer2peer &&
- pci_p2pdma_distance(to_pci_dev(obj->dev->dev), attach->dev, verbose_p2p_dist) < 0)
- attach->peer2peer = false;
-
- if (!attach->peer2peer && !xe_bo_can_migrate(gem_to_xe_bo(obj), XE_PL_TT))
- return -EOPNOTSUPP;
xe_pm_runtime_get(to_xe_device(obj->dev));
return 0;
@@ -70,13 +46,16 @@ static int xe_dma_buf_pin(struct dma_buf_attachment *attach)
struct xe_bo *bo = gem_to_xe_bo(obj);
struct xe_device *xe = xe_bo_device(bo);
struct drm_exec *exec = XE_VALIDATION_UNSUPPORTED;
- bool allow_vram = true;
+ bool allow_vram = dma_buf_sgt_p2p_allowed(attach);
int ret;
- list_for_each_entry(attach, &dmabuf->attachments, node) {
- if (!attach->peer2peer) {
- allow_vram = false;
- break;
+ if (allow_vram) {
+ /* Other attachments may be unmapped: ask what they accept */
+ list_for_each_entry(attach, &dmabuf->attachments, node) {
+ if (!dma_buf_attach_accepts_sgt_p2p(attach)) {
+ allow_vram = false;
+ break;
+ }
}
}
@@ -114,6 +93,8 @@ static void xe_dma_buf_unpin(struct dma_buf_attachment *attach)
static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
enum dma_data_direction dir)
{
+ struct device *dma_dev = dma_buf_sgt_dma_device(attach);
+ bool peer2peer = dma_buf_sgt_p2p_allowed(attach);
struct dma_buf *dma_buf = attach->dmabuf;
struct drm_gem_object *obj = dma_buf->priv;
struct xe_bo *bo = gem_to_xe_bo(obj);
@@ -124,11 +105,11 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
if (xe_bo_is_purged(bo))
return ERR_PTR(-ENOENT);
- if (!attach->peer2peer && !xe_bo_can_migrate(bo, XE_PL_TT))
+ if (!peer2peer && !xe_bo_can_migrate(bo, XE_PL_TT))
return ERR_PTR(-EOPNOTSUPP);
if (!xe_bo_is_pinned(bo)) {
- if (!attach->peer2peer)
+ if (!peer2peer)
r = xe_bo_migrate(bo, XE_PL_TT, NULL, exec);
else
r = xe_bo_validate(bo, NULL, false, exec);
@@ -144,7 +125,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
if (IS_ERR(sgt))
return sgt;
- if (dma_map_sgtable(attach->dev, sgt, dir,
+ if (dma_map_sgtable(dma_dev, sgt, dir,
DMA_ATTR_SKIP_CPU_SYNC))
goto error_free;
break;
@@ -153,7 +134,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
case XE_PL_VRAM1:
r = xe_ttm_vram_mgr_alloc_sgt(xe_bo_device(bo),
bo->ttm.resource, 0,
- bo->ttm.base.size, attach->dev,
+ bo->ttm.base.size, dma_dev,
dir, &sgt);
if (r)
return ERR_PTR(r);
@@ -174,12 +155,14 @@ static void xe_dma_buf_unmap(struct dma_buf_attachment *attach,
struct sg_table *sgt,
enum dma_data_direction dir)
{
+ struct device *dma_dev = dma_buf_sgt_dma_device(attach);
+
if (sg_page(sgt->sgl)) {
- dma_unmap_sgtable(attach->dev, sgt, dir, 0);
+ dma_unmap_sgtable(dma_dev, sgt, dir, 0);
sg_free_table(sgt);
kfree(sgt);
} else {
- xe_ttm_vram_mgr_free_sgt(attach->dev, dir, sgt);
+ xe_ttm_vram_mgr_free_sgt(dma_dev, dir, sgt);
}
}
@@ -225,18 +208,38 @@ static void xe_dma_buf_release(struct dma_buf *dmabuf)
drm_gem_dmabuf_release(dmabuf);
}
+static const struct dma_buf_mapping_sgt_exp_ops xe_dma_buf_sgt_ops = {
+ .map_dma_buf = xe_dma_buf_map,
+ .unmap_dma_buf = xe_dma_buf_unmap,
+};
+
+static int xe_dma_buf_match_mapping(struct dma_buf_match_args *args)
+{
+ struct drm_gem_object *obj = args->dmabuf->priv;
+ struct dma_buf_mapping_match sgt_match[2];
+ unsigned int num_match = 0;
+
+ sgt_match[num_match++] = DMA_BUF_EMAPPING_SGT_P2P(
+ &xe_dma_buf_sgt_ops, to_pci_dev(obj->dev->dev));
+
+ if (xe_bo_can_migrate(gem_to_xe_bo(obj), XE_PL_TT))
+ sgt_match[num_match++] =
+ DMA_BUF_EMAPPING_SGT(&xe_dma_buf_sgt_ops);
+
+ return dma_buf_match_mapping(args, sgt_match, num_match);
+}
+
static const struct dma_buf_ops xe_dmabuf_ops = {
.attach = xe_dma_buf_attach,
.detach = xe_dma_buf_detach,
.pin = xe_dma_buf_pin,
.unpin = xe_dma_buf_unpin,
- .map_dma_buf = xe_dma_buf_map,
- .unmap_dma_buf = xe_dma_buf_unmap,
.release = xe_dma_buf_release,
.begin_cpu_access = xe_dma_buf_begin_cpu_access,
.mmap = drm_gem_dmabuf_mmap,
.vmap = drm_gem_dmabuf_vmap,
.vunmap = drm_gem_dmabuf_vunmap,
+ .match_mapping = xe_dma_buf_match_mapping,
};
struct dma_buf *xe_gem_prime_export(struct drm_gem_object *obj, int flags)
--
2.54.0
More information about the Linux-nvme
mailing list