drm/xe/pf: Use migration-friendly VRAM auto-provisioning

Instead of trying very hard to find the largest fair VRAM (aka LMEM)
size that could be allocated for VFs on the current tile, pick some
smaller rounded down to power-of-two value that is more likely to be
provisioned in the same manner by the other PF instances.

In some cases, the outcome of above calculation might not be optimal,
but it's expected that admin will do fine-tuning using sysfs files.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patch.msgid.link/20260218205553.3561-6-michal.wajdeczko@intel.com

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
index f67c8822e592dc58eb8715e2ff59cfd3dd558074..72cd46554230fbe125b9a5fe46ab3a33148e3c9d 100644 (file)
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c
@@ -1900,6 +1900,28 @@ static u64 pf_estimate_fair_lmem(struct xe_gt *gt, unsigned int num_vfs)
        return fair;
 }
 
+static u64 pf_profile_fair_lmem(struct xe_gt *gt, unsigned int num_vfs)
+{
+       struct xe_tile *tile = gt_to_tile(gt);
+       bool admin_only_pf = xe_sriov_pf_admin_only(tile->xe);
+       u64 usable = xe_vram_region_usable_size(tile->mem.vram);
+       u64 spare = pf_get_min_spare_lmem(gt);
+       u64 available = usable > spare ? usable - spare : 0;
+       u64 shareable = ALIGN_DOWN(available, SZ_1G);
+       u64 alignment = pf_get_lmem_alignment(gt);
+       u64 fair;
+
+       if (admin_only_pf)
+               fair = div_u64(shareable, num_vfs);
+       else
+               fair = div_u64(shareable, 1 + num_vfs);
+
+       if (!admin_only_pf && fair)
+               fair = rounddown_pow_of_two(fair);
+
+       return ALIGN_DOWN(fair, alignment);
+}
+
 /**
  * xe_gt_sriov_pf_config_set_fair_lmem - Provision many VFs with fair LMEM.
  * @gt: the &xe_gt (can't be media)
@@ -1913,6 +1935,7 @@ static u64 pf_estimate_fair_lmem(struct xe_gt *gt, unsigned int num_vfs)
 int xe_gt_sriov_pf_config_set_fair_lmem(struct xe_gt *gt, unsigned int vfid,
                                        unsigned int num_vfs)
 {
+       u64 profile;
        u64 fair;
 
        xe_gt_assert(gt, vfid);
@@ -1929,6 +1952,12 @@ int xe_gt_sriov_pf_config_set_fair_lmem(struct xe_gt *gt, unsigned int vfid,
        if (!fair)
                return -ENOSPC;
 
+       profile = pf_profile_fair_lmem(gt, num_vfs);
+       fair = min(fair, profile);
+       if (fair < profile)
+               xe_gt_sriov_info(gt, "Using non-profile provisioning (%s %llu vs %llu)\n",
+                                "VRAM", fair, profile);
+
        return xe_gt_sriov_pf_config_bulk_set_lmem(gt, vfid, num_vfs, fair);
 }