linux-kernel - [PATCH v2 3/3] drm/xe/pf: Extend the VF LMEM BAR

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Message-ID: <20240919223557.1897608-4-michal.winiarski@intel.com>
Date: Fri, 20 Sep 2024 00:35:57 +0200
From: Michał Winiarski <michal.winiarski@...el.com>
To: <linux-pci@...r.kernel.org>, <intel-xe@...ts.freedesktop.org>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>, "Bjorn
 Helgaas" <bhelgaas@...gle.com>, Christian König
	<christian.koenig@....com>, Krzysztof Wilczyński
	<kw@...ux.com>
CC: Rodrigo Vivi <rodrigo.vivi@...el.com>, Michal Wajdeczko
	<michal.wajdeczko@...el.com>, Lucas De Marchi <lucas.demarchi@...el.com>,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
	<mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, David Airlie
	<airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Matt Roper
	<matthew.d.roper@...el.com>, Michał Winiarski
	<michal.winiarski@...el.com>
Subject: [PATCH v2 3/3] drm/xe/pf: Extend the VF LMEM BAR

Opt into extending the VF BAR.
LMEM is partitioned between multiple VFs, and we expect that the more
VFs we have, the less LMEM is assigned to each VF.
This means that we can achieve full LMEM BAR access without the need to
attempt full VF LMEM BAR resize via pci_resize_resource().

Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
---
 drivers/gpu/drm/xe/regs/xe_bars.h | 1 +
 drivers/gpu/drm/xe/xe_sriov_pf.c  | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/xe/regs/xe_bars.h b/drivers/gpu/drm/xe/regs/xe_bars.h
index ce05b6ae832f1..880140d6ccdca 100644
--- a/drivers/gpu/drm/xe/regs/xe_bars.h
+++ b/drivers/gpu/drm/xe/regs/xe_bars.h
@@ -7,5 +7,6 @@
 
 #define GTTMMADR_BAR			0 /* MMIO + GTT */
 #define LMEM_BAR			2 /* VRAM */
+#define VF_LMEM_BAR			9 /* VF VRAM */
 
 #endif
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf.c b/drivers/gpu/drm/xe/xe_sriov_pf.c
index 0f721ae17b266..a26719b87ac1e 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf.c
@@ -4,7 +4,9 @@
  */
 
 #include <drm/drm_managed.h>
+#include <linux/pci.h>
 
+#include "regs/xe_bars.h"
 #include "xe_assert.h"
 #include "xe_device.h"
 #include "xe_module.h"
@@ -80,8 +82,14 @@ bool xe_sriov_pf_readiness(struct xe_device *xe)
  */
 int xe_sriov_pf_init_early(struct xe_device *xe)
 {
+	int err;
+
 	xe_assert(xe, IS_SRIOV_PF(xe));
 
+	err = pci_iov_resource_extend(to_pci_dev(xe->drm.dev), VF_LMEM_BAR, true);
+	if (err)
+		xe_sriov_info(xe, "Failed to extend VF LMEM BAR: %d", err);
+
 	return drmm_mutex_init(&xe->drm, &xe->sriov.pf.master_lock);
 }
 
-- 
2.46.0