From: Jia Yao Date: Tue, 4 Aug 2026 16:50:55 +0000 (+0000) Subject: drm/xe/guc_ads: allocate UM queues in a separate BO X-Git-Tag: v7.2~13^2^2~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=99b01815957bd7d848420cb697f79ed11f7f215c;p=thirdparty%2Fkernel%2Flinux.git drm/xe/guc_ads: allocate UM queues in a separate BO 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 Cc: Matthew Auld Cc: # v6.12+ Signed-off-by: Jia Yao Reviewed-by: Matthew Auld Signed-off-by: Matthew Auld Link: https://patch.msgid.link/20260804165057.129529-2-jia.yao@intel.com (cherry picked from commit 6af05de0dc19bbf3aaeec2020fe48b37c834b811) Signed-off-by: Thomas Hellström --- diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h index 7ae1d9ac0574..57039cf42ea7 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 #include #include "xe_bo_types.h" @@ -548,6 +549,19 @@ void xe_bo_dev_fini(struct xe_bo_dev *bo_device); 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 4023700ff2a9..21cf3edef922 100644 --- a/drivers/gpu/drm/xe/xe_guc.c +++ b/drivers/gpu/drm/xe/xe_guc.c @@ -714,6 +714,12 @@ 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 c98454545a85..a411d6440ba6 100644 --- a/drivers/gpu/drm/xe/xe_guc_ads.c +++ b/drivers/gpu/drm/xe/xe_guc_ads.c @@ -63,10 +63,14 @@ 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 | @@ -98,10 +102,6 @@ ads_to_map(struct xe_guc_ads *ads) * +---------------------------------------+ * | padding | * +---------------------------------------+ <== 4K aligned - * | UM queues | - * +---------------------------------------+ - * | padding | - * +---------------------------------------+ <== 4K aligned * | private data | * +---------------------------------------+ * | padding | @@ -155,16 +155,6 @@ static size_t guc_ads_capture_size(struct xe_guc_ads *ads) return PAGE_ALIGN(ads->capture_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); @@ -205,22 +195,12 @@ 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); } @@ -409,6 +389,46 @@ 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; } ALLOW_ERROR_INJECTION(xe_guc_ads_init, ERRNO); /* See xe_pci_probe() */ @@ -820,7 +840,7 @@ 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; struct xe_guc *guc = ads_to_guc(ads); struct xe_device *xe = ads_to_xe(ads); u64 base_dpa; @@ -830,8 +850,14 @@ static void guc_um_init_params(struct xe_guc_ads *ads) with_dpa = !xe_guc_using_main_gamctrl_queues(guc); - 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) { /* diff --git a/drivers/gpu/drm/xe/xe_guc_ads_types.h b/drivers/gpu/drm/xe/xe_guc_ads_types.h index 48a8e092023f..845c1fbd93a4 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 */