linux-kernel - Re: [PATCH 11/26] drm/xe: Allow the caller to pass guc_buf

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Message-ID: <xak4eutwq2haltvwcsrxlixu2vumnsib3wnexrrnugcol4wayq@maabjjl6y6op>
Date: Tue, 21 Oct 2025 02:47:18 +0200
From: Michał Winiarski <michal.winiarski@...el.com>
To: Michal Wajdeczko <michal.wajdeczko@...el.com>
CC: Alex Williamson <alex.williamson@...hat.com>, Lucas De Marchi
	<lucas.demarchi@...el.com>, Thomas Hellström
	<thomas.hellstrom@...ux.intel.com>, Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Jason Gunthorpe <jgg@...pe.ca>, Yishai Hadas <yishaih@...dia.com>, Kevin Tian
	<kevin.tian@...el.com>, Shameer Kolothum
	<shameerali.kolothum.thodi@...wei.com>, <intel-xe@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
	<dri-devel@...ts.freedesktop.org>, Matthew Brost <matthew.brost@...el.com>,
	Jani Nikula <jani.nikula@...ux.intel.com>, Joonas Lahtinen
	<joonas.lahtinen@...ux.intel.com>, Tvrtko Ursulin <tursulin@...ulin.net>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, "Lukasz
 Laguna" <lukasz.laguna@...el.com>
Subject: Re: [PATCH 11/26] drm/xe: Allow the caller to pass guc_buf_cache size

On Mon, Oct 13, 2025 at 01:08:39PM +0200, Michal Wajdeczko wrote:
> 
> 
> On 10/11/2025 9:38 PM, Michał Winiarski wrote:
> > An upcoming change will use GuC buffer cache as a place where GuC
> > migration data will be stored, and the memory requirement for that is
> > larger than indirect data.
> > Allow the caller to pass the size based on the intended usecase.
> > 
> > Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
> > ---
> >  drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c | 2 +-
> >  drivers/gpu/drm/xe/xe_guc.c                 | 4 ++--
> >  drivers/gpu/drm/xe/xe_guc_buf.c             | 6 +++---
> >  drivers/gpu/drm/xe/xe_guc_buf.h             | 2 +-
> >  4 files changed, 7 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c b/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> > index d266882adc0e0..c273ce8087f56 100644
> > --- a/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> > +++ b/drivers/gpu/drm/xe/tests/xe_guc_buf_kunit.c
> > @@ -72,7 +72,7 @@ static int guc_buf_test_init(struct kunit *test)
> >  	kunit_activate_static_stub(test, xe_managed_bo_create_pin_map,
> >  				   replacement_xe_managed_bo_create_pin_map);
> >  
> > -	KUNIT_ASSERT_EQ(test, 0, xe_guc_buf_cache_init(&guc->buf));
> > +	KUNIT_ASSERT_EQ(test, 0, xe_guc_buf_cache_init(&guc->buf), SZ_8K);
> 
> SZ_8K added to wrong place ;)

As buildbots & CI already noticed :)

> >  
> >  	test->priv = &guc->buf;
> >  	return 0;
> > diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> > index d94490979adc0..ccc7c60ae9b77 100644
> > --- a/drivers/gpu/drm/xe/xe_guc.c
> > +++ b/drivers/gpu/drm/xe/xe_guc.c
> > @@ -809,7 +809,7 @@ static int vf_guc_init_post_hwconfig(struct xe_guc *guc)
> >  	if (err)
> >  		return err;
> >  
> > -	err = xe_guc_buf_cache_init(&guc->buf);
> > +	err = xe_guc_buf_cache_init(&guc->buf, SZ_8K);
> >  	if (err)
> >  		return err;
> >  
> > @@ -857,7 +857,7 @@ int xe_guc_init_post_hwconfig(struct xe_guc *guc)
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = xe_guc_buf_cache_init(&guc->buf);
> > +	ret = xe_guc_buf_cache_init(&guc->buf, SZ_8K);
> >  	if (ret)
> >  		return ret;
> >  
> > diff --git a/drivers/gpu/drm/xe/xe_guc_buf.c b/drivers/gpu/drm/xe/xe_guc_buf.c
> > index 1be26145f0b98..418ada00b99e3 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_buf.c
> > +++ b/drivers/gpu/drm/xe/xe_guc_buf.c
> > @@ -28,16 +28,16 @@ static struct xe_gt *cache_to_gt(struct xe_guc_buf_cache *cache)
> >   * @cache: the &xe_guc_buf_cache to initialize
> >   *
> >   * The Buffer Cache allows to obtain a reusable buffer that can be used to pass
> > - * indirect H2G data to GuC without a need to create a ad-hoc allocation.
> > + * data to GuC or read data from GuC without a need to create a ad-hoc allocation.
> >   *
> >   * Return: 0 on success or a negative error code on failure.
> >   */
> > -int xe_guc_buf_cache_init(struct xe_guc_buf_cache *cache)
> > +int xe_guc_buf_cache_init(struct xe_guc_buf_cache *cache, u32 size)
> >  {
> >  	struct xe_gt *gt = cache_to_gt(cache);
> >  	struct xe_sa_manager *sam;
> >  
> > -	sam = __xe_sa_bo_manager_init(gt_to_tile(gt), SZ_8K, 0, sizeof(u32));
> 
> maybe we should promote this magic SZ_8K as 
> 
> #define XE_GUC_BUF_CACHE_DEFAULT_SIZE SZ_8K

Ok.

Thanks,
-Michał

> 
> > +	sam = __xe_sa_bo_manager_init(gt_to_tile(gt), size, 0, sizeof(u32));
> >  	if (IS_ERR(sam))
> >  		return PTR_ERR(sam);
> >  	cache->sam = sam;
> > diff --git a/drivers/gpu/drm/xe/xe_guc_buf.h b/drivers/gpu/drm/xe/xe_guc_buf.h
> > index fe6b5ffe0d6eb..fe5cf3b183497 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_buf.h
> > +++ b/drivers/gpu/drm/xe/xe_guc_buf.h
> > @@ -11,7 +11,7 @@
> >  
> >  #include "xe_guc_buf_types.h"
> >  
> > -int xe_guc_buf_cache_init(struct xe_guc_buf_cache *cache);
> > +int xe_guc_buf_cache_init(struct xe_guc_buf_cache *cache, u32 size);
> >  u32 xe_guc_buf_cache_dwords(struct xe_guc_buf_cache *cache);
> >  struct xe_guc_buf xe_guc_buf_reserve(struct xe_guc_buf_cache *cache, u32 dwords);
> >  struct xe_guc_buf xe_guc_buf_from_data(struct xe_guc_buf_cache *cache,
>