Commit e448372e authored by Michal Wajdeczko's avatar Michal Wajdeczko
Browse files

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



Instead of trying very hard to find the largest fair GGTT 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 instance:

  num VFs | GGTT space (MiB)
  --------+-----------------
   63..57 | 56
   56..29 | 64
   28..15 | 128
   14..8  | 256
    7..4  | 512
    3..2  | 1024
       1  | 2048 (regular PF)
       1  | 3584 (admin only PF)

Note that due to FW/HW limitations we can't share all 4GiB GGTT
address space with VFs, so for the larger (>7) number of the VFs
the change in the outcome is happening at different points than
we have in case of GuC contexts/doorbells IDs.

Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: default avatarPiotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patch.msgid.link/20251112124408.8094-1-michal.wajdeczko@intel.com
parent aaecfadc

drivers/gpu/drm/xe/tests/xe_gt_sriov_pf_config_kunit.c

+46 −0
Original line number Diff line number Diff line
@@ -145,11 +145,57 @@ static void fair_doorbells(struct kunit *test) 
		KUNIT_ASSERT_EQ(test, SZ_128, pf_profile_fair_dbs(gt, num_vfs));

}



static void fair_ggtt_1vf(struct kunit *test)

{

	struct xe_gt *gt = test->priv;

	struct xe_device *xe = gt_to_xe(gt);



	pf_set_admin_mode(xe, false);

	KUNIT_ASSERT_FALSE(test, xe_sriov_pf_admin_only(xe));

	KUNIT_EXPECT_EQ(test, SZ_2G, pf_profile_fair_ggtt(gt, 1));



	pf_set_admin_mode(xe, true);

	KUNIT_ASSERT_TRUE(test, xe_sriov_pf_admin_only(xe));

	KUNIT_EXPECT_EQ(test, SZ_2G + SZ_1G + SZ_512M, pf_profile_fair_ggtt(gt, 1));

}



static void fair_ggtt(struct kunit *test)

{

	unsigned int num_vfs = (unsigned long)test->param_value;

	struct xe_gt *gt = test->priv;

	struct xe_device *xe = gt_to_xe(gt);

	u64 alignment = pf_get_ggtt_alignment(gt);

	u64 shareable = SZ_2G + SZ_1G + SZ_512M;



	pf_set_admin_mode(xe, false);

	KUNIT_ASSERT_FALSE(test, xe_sriov_pf_admin_only(xe));



	KUNIT_EXPECT_TRUE(test, IS_ALIGNED(pf_profile_fair_ggtt(gt, num_vfs), alignment));

	KUNIT_EXPECT_GE(test, shareable, num_vfs * pf_profile_fair_ggtt(gt, num_vfs));



	if (num_vfs > 56)

		KUNIT_ASSERT_EQ(test, SZ_64M - SZ_8M, pf_profile_fair_ggtt(gt, num_vfs));

	else if (num_vfs > 28)

		KUNIT_ASSERT_EQ(test, SZ_64M, pf_profile_fair_ggtt(gt, num_vfs));

	else if (num_vfs > 14)

		KUNIT_ASSERT_EQ(test, SZ_128M, pf_profile_fair_ggtt(gt, num_vfs));

	else if (num_vfs > 7)

		KUNIT_ASSERT_EQ(test, SZ_256M, pf_profile_fair_ggtt(gt, num_vfs));

	else if (num_vfs > 3)

		KUNIT_ASSERT_EQ(test, SZ_512M, pf_profile_fair_ggtt(gt, num_vfs));

	else if (num_vfs > 1)

		KUNIT_ASSERT_EQ(test, SZ_1G, pf_profile_fair_ggtt(gt, num_vfs));

	else

		KUNIT_ASSERT_EQ(test, SZ_2G, pf_profile_fair_ggtt(gt, num_vfs));

}



static struct kunit_case pf_gt_config_test_cases[] = {

	KUNIT_CASE(fair_contexts_1vf),

	KUNIT_CASE(fair_doorbells_1vf),

	KUNIT_CASE(fair_ggtt_1vf),

	KUNIT_CASE_PARAM(fair_contexts, num_vfs_gen_param),

	KUNIT_CASE_PARAM(fair_doorbells, num_vfs_gen_param),

	KUNIT_CASE_PARAM(fair_ggtt, num_vfs_gen_param),

	{}

};

drivers/gpu/drm/xe/xe_gt_sriov_pf_config.c

+23 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include "abi/guc_actions_sriov_abi.h"

#include "abi/guc_klvs_abi.h"



#include "regs/xe_gtt_defs.h"

#include "regs/xe_guc_regs.h"



#include "xe_bo.h"
@@ -697,6 +698,22 @@ static u64 pf_estimate_fair_ggtt(struct xe_gt *gt, unsigned int num_vfs) 
	return fair;

}



static u64 pf_profile_fair_ggtt(struct xe_gt *gt, unsigned int num_vfs)

{

	bool admin_only_pf = xe_sriov_pf_admin_only(gt_to_xe(gt));

	u64 shareable = ALIGN_DOWN(GUC_GGTT_TOP, SZ_512M);

	u64 alignment = pf_get_ggtt_alignment(gt);



	if (admin_only_pf && num_vfs == 1)

		return ALIGN_DOWN(shareable, alignment);



	/* need to hardcode due to ~512M of GGTT being reserved */

	if (num_vfs > 56)

		return SZ_64M - SZ_8M;



	return rounddown_pow_of_two(shareable / num_vfs);

}



/**

 * xe_gt_sriov_pf_config_set_fair_ggtt - Provision many VFs with fair GGTT.

 * @gt: the &xe_gt (can't be media)
@@ -710,6 +727,7 @@ static u64 pf_estimate_fair_ggtt(struct xe_gt *gt, unsigned int num_vfs) 
int xe_gt_sriov_pf_config_set_fair_ggtt(struct xe_gt *gt, unsigned int vfid,

					unsigned int num_vfs)

{

	u64 profile = pf_profile_fair_ggtt(gt, num_vfs);

	u64 fair;



	xe_gt_assert(gt, vfid);
@@ -723,6 +741,11 @@ int xe_gt_sriov_pf_config_set_fair_ggtt(struct xe_gt *gt, unsigned int vfid, 
	if (!fair)

		return -ENOSPC;



	fair = min(fair, profile);

	if (fair < profile)

		xe_gt_sriov_info(gt, "Using non-profile provisioning (%s %llu vs %llu)\n",

				 "GGTT", fair, profile);



	return xe_gt_sriov_pf_config_bulk_set_ggtt(gt, vfid, num_vfs, fair);

}