Re: [PATCH v2 05/11] drm/xe/guc: Add page reclamation interface to GuC

[Matthew Brost <matthew.brost@intel.com>]

On Thu, Nov 27, 2025 at 07:02:06AM +0800, Brian Nguyen wrote:
> Add page reclamation related changes to GuC interface, handlers, and
> senders to support page reclamation.
> 
> Currently TLB invalidations will perform an entire PPC flush in order to
> prevent stale memory access for noncoherent system memory. Page
> reclamation is an extension of the typical TLB invalidation
> workflow, allowing disabling of full PPC flush and enable selective PPC
> flushing. Selective flushing will be decided by a list of pages whom's
> address is passed to GuC at time of action.
> 
> Page reclamation interfaces require at least GuC FW ver 70.31.0.
> 
> v2:
>  - Moved send_page_reclaim to first patch usage.
>  - Add comments explaining shared done handler. (Matthew B)
>  - Add FW version fallback to disable page reclaim
>    on older versions. (Matthew B, Shuicheng)
> 
> Signed-off-by: Brian Nguyen <brian3.nguyen@intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Matthew Brost <matthew.brost@intel.com>

> Cc: Shuicheng Lin <shuicheng.lin@intel.com>
> ---
>  drivers/gpu/drm/xe/abi/guc_actions_abi.h |  2 ++
>  drivers/gpu/drm/xe/xe_guc.c              |  4 ++++
>  drivers/gpu/drm/xe/xe_guc_ct.c           | 17 +++++++++++++++++
>  drivers/gpu/drm/xe/xe_guc_fwif.h         |  1 +
>  4 files changed, 24 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/abi/guc_actions_abi.h b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> index 47756e4674a1..11de3bdf69b5 100644
> --- a/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> +++ b/drivers/gpu/drm/xe/abi/guc_actions_abi.h
> @@ -151,6 +151,8 @@ enum xe_guc_action {
>  	XE_GUC_ACTION_TLB_INVALIDATION = 0x7000,
>  	XE_GUC_ACTION_TLB_INVALIDATION_DONE = 0x7001,
>  	XE_GUC_ACTION_TLB_INVALIDATION_ALL = 0x7002,
> +	XE_GUC_ACTION_PAGE_RECLAMATION = 0x7003,
> +	XE_GUC_ACTION_PAGE_RECLAMATION_DONE = 0x7004,
>  	XE_GUC_ACTION_STATE_CAPTURE_NOTIFICATION = 0x8002,
>  	XE_GUC_ACTION_NOTIFY_FLUSH_LOG_BUFFER_TO_FILE = 0x8003,
>  	XE_GUC_ACTION_NOTIFY_CRASH_DUMP_POSTED = 0x8004,
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index d6672cf30d3e..89b206c1eb86 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -767,6 +767,10 @@ int xe_guc_init(struct xe_guc *guc)
>  	if (!xe_uc_fw_is_enabled(&guc->fw))
>  		return 0;
>  
> +	/* Disable page reclaim if GuC FW does not support */
> +	if (GUC_FIRMWARE_VER(guc) < MAKE_GUC_VER(70, 31, 0))
> +		xe->info.has_page_reclaim_hw_assist = false;
> +
>  	if (IS_SRIOV_VF(xe)) {
>  		ret = xe_guc_ct_init(&guc->ct);
>  		if (ret)
> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
> index 02b4588fece0..b9e406d69414 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> @@ -1369,6 +1369,7 @@ static int parse_g2h_event(struct xe_guc_ct *ct, u32 *msg, u32 len)
>  	case XE_GUC_ACTION_DEREGISTER_CONTEXT_DONE:
>  	case XE_GUC_ACTION_SCHED_ENGINE_MODE_DONE:
>  	case XE_GUC_ACTION_TLB_INVALIDATION_DONE:
> +	case XE_GUC_ACTION_PAGE_RECLAMATION_DONE:
>  		g2h_release_space(ct, len);
>  	}
>  
> @@ -1555,6 +1556,15 @@ static int process_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
>  		ret = xe_guc_pagefault_handler(guc, payload, adj_len);
>  		break;
>  	case XE_GUC_ACTION_TLB_INVALIDATION_DONE:
> +	case XE_GUC_ACTION_PAGE_RECLAMATION_DONE:
> +		/*
> +		 * Page reclamation is an extension of TLB invalidation. Both
> +		 * operations share the same seqno and fence. When either
> +		 * action completes, we need to signal the corresponding
> +		 * fence. Since the handling logic (lookup fence by seqno,
> +		 * fence signalling) is identical, we use the same handler
> +		 * for both G2H events.
> +		 */
>  		ret = xe_guc_tlb_inval_done_handler(guc, payload, adj_len);
>  		break;
>  	case XE_GUC_ACTION_GUC2PF_RELAY_FROM_VF:
> @@ -1720,6 +1730,7 @@ static int g2h_read(struct xe_guc_ct *ct, u32 *msg, bool fast_path)
>  		switch (action) {
>  		case XE_GUC_ACTION_REPORT_PAGE_FAULT_REQ_DESC:
>  		case XE_GUC_ACTION_TLB_INVALIDATION_DONE:
> +		case XE_GUC_ACTION_PAGE_RECLAMATION_DONE:
>  			break;	/* Process these in fast-path */
>  		default:
>  			return 0;
> @@ -1756,6 +1767,12 @@ static void g2h_fast_path(struct xe_guc_ct *ct, u32 *msg, u32 len)
>  		ret = xe_guc_pagefault_handler(guc, payload, adj_len);
>  		break;
>  	case XE_GUC_ACTION_TLB_INVALIDATION_DONE:
> +	case XE_GUC_ACTION_PAGE_RECLAMATION_DONE:
> +		/*
> +		 * Seqno and fence handling of page reclamation and TLB
> +		 * invalidation is identical, so we can use the same handler
> +		 * for both actions.
> +		 */
>  		__g2h_release_space(ct, len);
>  		ret = xe_guc_tlb_inval_done_handler(guc, payload, adj_len);
>  		break;
> diff --git a/drivers/gpu/drm/xe/xe_guc_fwif.h b/drivers/gpu/drm/xe/xe_guc_fwif.h
> index 7d93c2749485..5aa6fb249be9 100644
> --- a/drivers/gpu/drm/xe/xe_guc_fwif.h
> +++ b/drivers/gpu/drm/xe/xe_guc_fwif.h
> @@ -16,6 +16,7 @@
>  #define G2H_LEN_DW_DEREGISTER_CONTEXT		3
>  #define G2H_LEN_DW_TLB_INVALIDATE		3
>  #define G2H_LEN_DW_G2G_NOTIFY_MIN		3
> +#define G2H_LEN_DW_PAGE_RECLAMATION		3
>  
>  #define GUC_ID_MAX			65535
>  #define GUC_ID_UNKNOWN			0xffffffff
> -- 
> 2.52.0
>