On 9/17/2025 11:37 PM, Lucas De Marchi wrote:
> Now that xe_pci.c calls the rebar directly, it doens't make sense to
typo: doesn't
> keep it in xe_vram.c since it's closer to the PCI initialization than to
> the vram. Move it to its own file.
s/vram/VRAM
>
> While at it, add a better comment to document the possible values for
> the vram_bar_size module parameter.
if better comment is needed, shouldn't it be done in MODULE_PARM_DESC ?
>
> Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
> ---
> drivers/gpu/drm/xe/Makefile | 1 +
> drivers/gpu/drm/xe/xe_pci.c | 3 +-
> drivers/gpu/drm/xe/xe_pci_rebar.c | 125
> ++++++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_pci_rebar.h | 13 ++++
> drivers/gpu/drm/xe/xe_vram.c | 109 ---------------------------------
> drivers/gpu/drm/xe/xe_vram.h | 1 -
> 6 files changed, 141 insertions(+), 111 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index 7a065c98a3b85..5a66d7a53d0db 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -95,6 +95,7 @@ xe-y += xe_bb.o \
> xe_observation.o \
> xe_pat.o \
> xe_pci.o \
> + xe_pci_rebar.o \
> xe_pcode.o \
> xe_pm.o \
> xe_preempt_fence.o \
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 1f4120b535137..6cc5e7b6901a8 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -27,6 +27,7 @@
> #include "xe_macros.h"
> #include "xe_mmio.h"
> #include "xe_module.h"
> +#include "xe_pci_rebar.h"
> #include "xe_pci_sriov.h"
> #include "xe_pci_types.h"
> #include "xe_pm.h"
> @@ -866,7 +867,7 @@ static int xe_pci_probe(struct pci_dev *pdev, const
> struct pci_device_id *ent)
> if (err)
> return err;
>
> - xe_vram_resize_bar(xe);
> + xe_pci_rebar(xe);
>
> err = xe_device_probe_early(xe);
> /*
> diff --git a/drivers/gpu/drm/xe/xe_pci_rebar.c
> b/drivers/gpu/drm/xe/xe_pci_rebar.c
> new file mode 100644
> index 0000000000000..e04416630b573
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_pci_rebar.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#include "xe_pci_rebar.h"
as we have HDRTEST enabled, does it still make sense to have
this header outside of normal xe headers listed below ?
> +
> +#include <linux/pci.h>
> +#include <linux/types.h>
> +
> +#include <drm/drm_print.h>
> +
> +#include "regs/xe_bars.h"
> +#include "xe_device_types.h"
> +#include "xe_module.h"
> +
> +#define BAR_SIZE_SHIFT 20
> +
> +static void release_bars(struct pci_dev *pdev)
> +{
> + int resno;
> +
> + for (resno = PCI_STD_RESOURCES; resno < PCI_STD_RESOURCE_END; resno++) {
> + if (pci_resource_len(pdev, resno))
> + pci_release_resource(pdev, resno);
> + }
> +}
> +
> +static void resize_bar(struct xe_device *xe, int resno, resource_size_t size)
> +{
> + struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> + int bar_size = pci_rebar_bytes_to_size(size);
> + int ret;
> +
> + release_bars(pdev);
> +
> + ret = pci_resize_resource(pdev, resno, bar_size);
> + if (ret) {
> + drm_info(&xe->drm, "Failed to resize BAR%d to %dM (%pe).
> Consider enabling 'Resizable BAR' support in your BIOS\n",
maybe "%dMiB" as used below?
> + resno, 1 << bar_size, ERR_PTR(ret));
> + return;
> + }
> +
> + drm_info(&xe->drm, "BAR%d resized to %dM\n", resno, 1 << bar_size);
we can use
xe_info(xe, ...
> +}
> +
please add kernel-doc
> +void xe_pci_rebar(struct xe_device *xe)
> +{
> + int force_vram_bar_size = xe_modparam.force_vram_bar_size;
> + struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> + struct pci_bus *root = pdev->bus;
> + resource_size_t current_size;
> + resource_size_t rebar_size;
> + struct resource *root_res;
> + u32 bar_size_mask;
> + u32 pci_cmd;
> + int i;
> +
> + /* gather some relevant info */
> + current_size = pci_resource_len(pdev, LMEM_BAR);
> + bar_size_mask = pci_rebar_get_possible_sizes(pdev, LMEM_BAR);
> +
> + if (!bar_size_mask)
> + return;
> +
> + /*
> + * Handle force_vram_bar_size:
> + * - negative: resize is disabled
> + * - 0: try to resize to maximum possible
> + * - positive: resize to specific value
> + */
do we really need to duplicate modparam description from xe_module.c ?
> + if (force_vram_bar_size < 0)
> + return;
> +
> + if (force_vram_bar_size) {
> + u32 bar_size_bit;
> +
> + rebar_size = force_vram_bar_size * (resource_size_t)SZ_1M;
> +
> + bar_size_bit = bar_size_mask &
> BIT(pci_rebar_bytes_to_size(rebar_size));
> +
> + if (!bar_size_bit) {
> + drm_info(&xe->drm,
> + "Requested size: %lluMiB is not supported by
> rebar sizes: 0x%x. Leaving default: %lluMiB\n",
> + (u64)rebar_size >> 20, bar_size_mask,
> (u64)current_size >> 20);
> + return;
> + }
> +
> + rebar_size = 1ULL << (__fls(bar_size_bit) + BAR_SIZE_SHIFT);
> +
> + if (rebar_size == current_size)
> + return;
> + } else {
> + rebar_size = 1ULL << (__fls(bar_size_mask) + BAR_SIZE_SHIFT);
> +
> + /* only resize if larger than current */
> + if (rebar_size <= current_size)
> + return;
> + }
> +
> + drm_info(&xe->drm, "Attempting to resize bar from %lluMiB -> %lluMiB\n",
> + (u64)current_size >> 20, (u64)rebar_size >> 20);
> +
> + while (root->parent)
> + root = root->parent;
> +
> + pci_bus_for_each_resource(root, root_res, i) {
> + if (root_res && root_res->flags & (IORESOURCE_MEM |
> IORESOURCE_MEM_64) &&
> + (u64)root_res->start > 0x100000000ul)
> + break;
> + }
> +
> + if (!root_res) {
> + drm_info(&xe->drm, "Can't resize VRAM BAR - platform support is
> missing. Consider enabling 'Resizable BAR' support in your BIOS\n");
> + return;
> + }
> +
> + pci_read_config_dword(pdev, PCI_COMMAND, &pci_cmd);
> + pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd &
> ~PCI_COMMAND_MEMORY);
> +
> + resize_bar(xe, LMEM_BAR, rebar_size);
> +
> + pci_assign_unassigned_bus_resources(pdev->bus);
> + pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_pci_rebar.h
> b/drivers/gpu/drm/xe/xe_pci_rebar.h
> new file mode 100644
> index 0000000000000..c87aa58aee718
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_pci_rebar.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2025 Intel Corporation
> + */
> +
> +#ifndef _XE_PCI_REBAR_H_
> +#define _XE_PCI_REBAR_H_
> +
> +struct xe_device;
> +
> +void xe_pci_rebar(struct xe_device *xe);
> +
> +#endif
> diff --git a/drivers/gpu/drm/xe/xe_vram.c b/drivers/gpu/drm/xe/xe_vram.c
> index 4fb5a8426531a..caab5c1ff7ba9 100644
> --- a/drivers/gpu/drm/xe/xe_vram.c
> +++ b/drivers/gpu/drm/xe/xe_vram.c
> @@ -24,115 +24,6 @@
> #include "xe_vram.h"
> #include "xe_vram_types.h"
>
> -#define BAR_SIZE_SHIFT 20
> -
> -static void release_bars(struct pci_dev *pdev)
> -{
> - int resno;
> -
> - for (resno = PCI_STD_RESOURCES; resno < PCI_STD_RESOURCE_END; resno++) {
> - if (pci_resource_len(pdev, resno))
> - pci_release_resource(pdev, resno);
> - }
> -}
> -
> -static void resize_bar(struct xe_device *xe, int resno, resource_size_t size)
> -{
> - struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> - int bar_size = pci_rebar_bytes_to_size(size);
> - int ret;
> -
> - release_bars(pdev);
> -
> - ret = pci_resize_resource(pdev, resno, bar_size);
> - if (ret) {
> - drm_info(&xe->drm, "Failed to resize BAR%d to %dM (%pe).
> Consider enabling 'Resizable BAR' support in your BIOS\n",
> - resno, 1 << bar_size, ERR_PTR(ret));
> - return;
> - }
> -
> - drm_info(&xe->drm, "BAR%d resized to %dM\n", resno, 1 << bar_size);
> -}
> -
> -/*
> - * if force_vram_bar_size is set, attempt to set to the requested size
> - * else set to maximum possible size
> - */
> -void xe_vram_resize_bar(struct xe_device *xe)
> -{
> - int force_vram_bar_size = xe_modparam.force_vram_bar_size;
> - struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
> - struct pci_bus *root = pdev->bus;
> - resource_size_t current_size;
> - resource_size_t rebar_size;
> - struct resource *root_res;
> - u32 bar_size_mask;
> - u32 pci_cmd;
> - int i;
> -
> - /* gather some relevant info */
> - current_size = pci_resource_len(pdev, LMEM_BAR);
> - bar_size_mask = pci_rebar_get_possible_sizes(pdev, LMEM_BAR);
> -
> - if (!bar_size_mask)
> - return;
> -
> - if (force_vram_bar_size < 0)
> - return;
> -
> - /* set to a specific size? */
> - if (force_vram_bar_size) {
> - u32 bar_size_bit;
> -
> - rebar_size = force_vram_bar_size * (resource_size_t)SZ_1M;
> -
> - bar_size_bit = bar_size_mask &
> BIT(pci_rebar_bytes_to_size(rebar_size));
> -
> - if (!bar_size_bit) {
> - drm_info(&xe->drm,
> - "Requested size: %lluMiB is not supported by
> rebar sizes: 0x%x. Leaving default: %lluMiB\n",
> - (u64)rebar_size >> 20, bar_size_mask,
> (u64)current_size >> 20);
> - return;
> - }
> -
> - rebar_size = 1ULL << (__fls(bar_size_bit) + BAR_SIZE_SHIFT);
> -
> - if (rebar_size == current_size)
> - return;
> - } else {
> - rebar_size = 1ULL << (__fls(bar_size_mask) + BAR_SIZE_SHIFT);
> -
> - /* only resize if larger than current */
> - if (rebar_size <= current_size)
> - return;
> - }
> -
> - drm_info(&xe->drm, "Attempting to resize bar from %lluMiB -> %lluMiB\n",
> - (u64)current_size >> 20, (u64)rebar_size >> 20);
> -
> - while (root->parent)
> - root = root->parent;
> -
> - pci_bus_for_each_resource(root, root_res, i) {
> - if (root_res && root_res->flags & (IORESOURCE_MEM |
> IORESOURCE_MEM_64) &&
> - (u64)root_res->start > 0x100000000ul)
> - break;
> - }
> -
> - if (!root_res) {
> - drm_info(&xe->drm, "Can't resize VRAM BAR - platform support is
> missing. Consider enabling 'Resizable BAR' support in your BIOS\n");
> - return;
> - }
> -
> - pci_read_config_dword(pdev, PCI_COMMAND, &pci_cmd);
> - pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd &
> ~PCI_COMMAND_MEMORY);
> -
> - resize_bar(xe, LMEM_BAR, rebar_size);
> -
> - pci_assign_unassigned_bus_resources(pdev->bus);
> - pci_write_config_dword(pdev, PCI_COMMAND, pci_cmd);
> -}
> -
> static bool resource_is_valid(struct pci_dev *pdev, int bar)
> {
> if (!pci_resource_flags(pdev, bar))
> diff --git a/drivers/gpu/drm/xe/xe_vram.h b/drivers/gpu/drm/xe/xe_vram.h
> index 13505cfb184dc..72860f714fc66 100644
> --- a/drivers/gpu/drm/xe/xe_vram.h
> +++ b/drivers/gpu/drm/xe/xe_vram.h
> @@ -11,7 +11,6 @@
> struct xe_device;
> struct xe_vram_region;
>
> -void xe_vram_resize_bar(struct xe_device *xe);
> int xe_vram_probe(struct xe_device *xe);
>
> struct xe_vram_region *xe_vram_region_alloc(struct xe_device *xe, u8 id, u32
> placement);
>
