[PATCH 1/3] drm/xe/guc_ads: allocate UM queues in a separate BO
Jia Yao <[email protected]>
| Newsgroups | org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
Move the UM queues into a dedicated BO (ads->um_queue_bo) and avoid
CPU memset operations on it, which eliminates the CPU as a potential
cacheline-polluting agent and helps maintain consistency between GAM
writes and GuC reads.
We also need to ensure the base_dpa for the queue is contiguous on hw
where this is used instead of a GGTT address. Another good reason to
split this out to a separate BO.
Fixes: 9c57bc08652a ("drm/xe/lnl: Drop force_probe requirement")
Cc: Gwan-gyeong Mun <[email protected]>
Cc: Matthew Auld <[email protected]>
Cc: <[email protected]> # v6.12+
Signed-off-by: Jia Yao <[email protected]>
Reviewed-by: Matthew Auld <[email protected]>
Signed-off-by: Matthew Auld <[email protected]>
Link: https://patch.msgid.link/[email protected]
(cherry picked from commit 6af05de0dc19bbf3aaeec2020fe48b37c834b811)
Signed-off-by: Thomas Hellström <[email protected]>
(cherry picked from commit 99b01815957bd7d848420cb697f79ed11f7f215c)
---
drivers/gpu/drm/xe/xe_bo.h | 14 +++++
drivers/gpu/drm/xe/xe_guc.c | 6 ++
drivers/gpu/drm/xe/xe_guc_ads.c | 90 +++++++++++++++++----------
drivers/gpu/drm/xe/xe_guc_ads_types.h | 5 ++
4 files changed, 83 insertions(+), 32 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
index 556ce5390009..4640d311b5c5 100644
--- a/drivers/gpu/drm/xe/xe_bo.h
+++ b/drivers/gpu/drm/xe/xe_bo.h
@@ -6,6 +6,7 @@
#ifndef _XE_BO_H_
#define _XE_BO_H_
+#include <drm/drm_prime.h>
#include <drm/ttm/ttm_tt.h>
#include "xe_bo_types.h"
@@ -316,6 +317,19 @@ void xe_bo_put_commit(struct llist_head *deferred);
struct sg_table *xe_bo_sg(struct xe_bo *bo);
+/**
+ * xe_bo_sg_is_contiguous() - Check if a BO's DMA address space is contiguous.
+ * @bo: the BO to check (must have a valid sg table, i.e. !xe_bo_is_vram())
+ * @len: required contiguous length in bytes
+ *
+ * Returns true if the first @len bytes of the BO are mapped to a contiguous
+ * DMA address range.
+ */
+static inline bool xe_bo_sg_is_contiguous(struct xe_bo *bo, size_t len)
+{
+ return drm_prime_get_contiguous_size(xe_bo_sg(bo)) >= len;
+}
+
/*
* xe_sg_segment_size() - Provides upper limit for sg segment size.
* @dev: device pointer
diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index bedd9894e182..75ab0730c6cc 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -293,6 +293,12 @@ static int xe_guc_realloc_post_hwconfig(struct xe_guc *guc)
if (ret)
return ret;
+ if (guc->ads.um_queue_bo) {
+ ret = xe_managed_bo_reinit_in_vram(xe, tile, &guc->ads.um_queue_bo);
+ if (ret)
+ return ret;
+ }
+
return 0;
}
diff --git a/drivers/gpu/drm/xe/xe_guc_ads.c b/drivers/gpu/drm/xe/xe_guc_ads.c
index e144fd41c0a7..1bb74e04ed77 100644
--- a/drivers/gpu/drm/xe/xe_guc_ads.c
+++ b/drivers/gpu/drm/xe/xe_guc_ads.c
@@ -60,10 +60,14 @@ ads_to_map(struct xe_guc_ads *ads)
/*
* The Additional Data Struct (ADS) has pointers for different buffers used by
- * the GuC. One single gem object contains the ADS struct itself (guc_ads) and
- * all the extra buffers indirectly linked via the ADS struct's entries.
+ * the GuC. One gem object (ads->bo) contains the ADS struct itself (guc_ads)
+ * and most of the extra buffers linked via the ADS struct's entries. The UM
+ * fault queues (PAGE_FAULT, PAGE_FAULT_RESPONSE, ACCESS_COUNTER rings) are
+ * kept in a separate BO (ads->um_queue_bo) so that the full memset of ads->bo
+ * performed on every GT reset does not discard fault descriptors already
+ * written into the rings by the GPU.
*
- * Layout of the ADS blob allocated for the GuC:
+ * Layout of the ADS blob (ads->bo):
*
* +---------------------------------------+ <== base
* | guc_ads |
@@ -95,10 +99,6 @@ ads_to_map(struct xe_guc_ads *ads)
* +---------------------------------------+
* | padding |
* +---------------------------------------+ <== 4K aligned
- * | UM queues |
- * +---------------------------------------+
- * | padding |
- * +---------------------------------------+ <== 4K aligned
* | private data |
* +---------------------------------------+
* | padding |
@@ -153,16 +153,6 @@ static size_t guc_ads_capture_size(struct xe_guc_ads *ads)
return PAGE_ALIGN(PAGE_SIZE);
}
-static size_t guc_ads_um_queues_size(struct xe_guc_ads *ads)
-{
- struct xe_device *xe = ads_to_xe(ads);
-
- if (!xe->info.has_usm)
- return 0;
-
- return GUC_UM_QUEUE_SIZE * GUC_UM_HW_QUEUE_MAX;
-}
-
static size_t guc_ads_private_data_size(struct xe_guc_ads *ads)
{
return PAGE_ALIGN(ads_to_guc(ads)->fw.private_data_size);
@@ -203,22 +193,12 @@ static size_t guc_ads_capture_offset(struct xe_guc_ads *ads)
return PAGE_ALIGN(offset);
}
-static size_t guc_ads_um_queues_offset(struct xe_guc_ads *ads)
-{
- u32 offset;
-
- offset = guc_ads_capture_offset(ads) +
- guc_ads_capture_size(ads);
-
- return PAGE_ALIGN(offset);
-}
-
static size_t guc_ads_private_data_offset(struct xe_guc_ads *ads)
{
size_t offset;
- offset = guc_ads_um_queues_offset(ads) +
- guc_ads_um_queues_size(ads);
+ offset = guc_ads_capture_offset(ads) +
+ guc_ads_capture_size(ads);
return PAGE_ALIGN(offset);
}
@@ -416,6 +396,46 @@ int xe_guc_ads_init(struct xe_guc_ads *ads)
ads->bo = bo;
+ if (xe->info.has_usm) {
+ /*
+ * Allocate a separate BO for the HW fault ring (UM queues).
+ *
+ * Round the size up to the next power of two so that
+ * (system memory, no IOMMU) the TTM pool issues a single
+ * alloc_pages(order=N) call, maximising the chance of getting
+ * a physically contiguous block. GuC requires contiguous DPA.
+ */
+ size_t um_size = roundup_pow_of_two(GUC_UM_QUEUE_SIZE *
+ GUC_UM_HW_QUEUE_MAX);
+
+ u32 um_flags = XE_BO_FLAG_SYSTEM |
+ XE_BO_FLAG_GGTT |
+ XE_BO_FLAG_GGTT_INVALIDATE |
+ XE_BO_FLAG_PINNED_NORESTORE;
+
+ bo = xe_managed_bo_create_pin_map(xe, tile, um_size, um_flags);
+ if (IS_ERR(bo))
+ return PTR_ERR(bo);
+
+ /*
+ * On pre-Xe3p platforms, GAM (not GuC) accesses the UM queue
+ * ring via base_dpa, which must be a contiguous DMA address
+ * range. Verify that the allocated pages are contiguous in
+ * DMA address space.
+ */
+ if (!xe_bo_is_vram(bo) &&
+ !xe_guc_using_main_gamctrl_queues(ads_to_guc(ads)) &&
+ unlikely(!xe_bo_sg_is_contiguous(bo,
+ GUC_UM_QUEUE_SIZE *
+ GUC_UM_HW_QUEUE_MAX))) {
+ drm_err(&xe->drm,
+ "UM fault queue memory is not contiguous in DMA address space; GAM requires contiguous DPA\n");
+ return -ENOMEM;
+ }
+
+ ads->um_queue_bo = bo;
+ }
+
return 0;
}
@@ -684,13 +704,19 @@ static void guc_mmio_reg_state_init(struct xe_guc_ads *ads)
static void guc_um_init_params(struct xe_guc_ads *ads)
{
- u32 um_queue_offset = guc_ads_um_queues_offset(ads);
+ struct xe_bo *um_bo = ads->um_queue_bo;
u64 base_dpa;
u32 base_ggtt;
int i;
- base_ggtt = xe_bo_ggtt_addr(ads->bo) + um_queue_offset;
- base_dpa = xe_bo_main_addr(ads->bo, PAGE_SIZE) + um_queue_offset;
+ if (um_bo) {
+ /* All USM platforms: UM queues in dedicated um_queue_bo */
+ base_ggtt = xe_bo_ggtt_addr(um_bo);
+ base_dpa = xe_bo_main_addr(um_bo, PAGE_SIZE);
+ } else {
+ /* Platform does not support USM: no UM queues, nothing to do */
+ return;
+ }
for (i = 0; i < GUC_UM_HW_QUEUE_MAX; ++i) {
ads_blob_write(ads, um_init_params.queue_params[i].base_dpa,
diff --git a/drivers/gpu/drm/xe/xe_guc_ads_types.h b/drivers/gpu/drm/xe/xe_guc_ads_types.h
index 2de5decfe0fd..99ad22bda325 100644
--- a/drivers/gpu/drm/xe/xe_guc_ads_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_ads_types.h
@@ -16,6 +16,11 @@ struct xe_bo;
struct xe_guc_ads {
/** @bo: XE BO for GuC ads blob */
struct xe_bo *bo;
+ /**
+ * @um_queue_bo: Dedicated BO for the HW fault ring (UM queues).
+ * NULL if the platform does not support USM.
+ */
+ struct xe_bo *um_queue_bo;
/** @golden_lrc_size: golden LRC size */
size_t golden_lrc_size;
/** @regset_size: size of register set passed to GuC for save/restore */
--
2.43.0