On Wed, Mar 20, 2024 at 04:14:26PM +0530, Aravind Iddamsetty wrote:
> PCI subsystem provides callbacks to inform the driver about a request to
> do function level reset by user, initiated by writing to sysfs entry
> /sys/bus/pci/devices/.../reset. This will allow the driver to handle FLR
> without the need to do unbind and rebind as the driver needs to
> reinitialize the device afresh post FLR.
>
> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/xe/Makefile | 1 +
> drivers/gpu/drm/xe/xe_device_types.h | 3 +
> drivers/gpu/drm/xe/xe_gt.c | 31 ++++++---
> drivers/gpu/drm/xe/xe_gt.h | 1 +
> drivers/gpu/drm/xe/xe_pci.c | 53 ++++++++++++++--
> drivers/gpu/drm/xe/xe_pci.h | 6 +-
> drivers/gpu/drm/xe/xe_pci_err.c | 94 ++++++++++++++++++++++++++++
> 7 files changed, 174 insertions(+), 15 deletions(-)
> create mode 100644 drivers/gpu/drm/xe/xe_pci_err.c
>
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index 3c3e67885559..1447712fec65 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -114,6 +114,7 @@ xe-y += xe_bb.o \
> xe_module.o \
> xe_pat.o \
> xe_pci.o \
> + xe_pci_err.o \
> xe_pcode.o \
> xe_pm.o \
> xe_preempt_fence.o \
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index 9785eef2e5a4..e9b8c7cbb428 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -455,6 +455,9 @@ struct xe_device {
> /** @needs_flr_on_fini: requests function-reset on fini */
> bool needs_flr_on_fini;
>
> + /** @pci_state: PCI state of device */
> + struct pci_saved_state *pci_state;
> +
> /* private: */
>
> #if IS_ENABLED(CONFIG_DRM_XE_DISPLAY)
> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
> index 85408e7a932b..437874a9a5a0 100644
> --- a/drivers/gpu/drm/xe/xe_gt.c
> +++ b/drivers/gpu/drm/xe/xe_gt.c
> @@ -629,6 +629,26 @@ static int do_gt_restart(struct xe_gt *gt)
> return 0;
> }
>
> +/* Idle the GT */
> +int xe_idle_gt(struct xe_gt *gt)
> +{
> + int err;
> +
> + xe_gt_sanitize(gt);
> +
> + xe_uc_gucrc_disable(>->uc);
> + xe_uc_stop_prepare(>->uc);
> + xe_gt_pagefault_reset(gt);
> +
> + err = xe_uc_stop(>->uc);
> + if (err)
> + return err;
> +
> + xe_gt_tlb_invalidation_reset(gt);
> +
> + return err;
> +}
> +
> static int gt_reset(struct xe_gt *gt)
> {
> int err;
> @@ -645,21 +665,12 @@ static int gt_reset(struct xe_gt *gt)
> }
>
> xe_pm_runtime_get(gt_to_xe(gt));
> - xe_gt_sanitize(gt);
>
> err = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> if (err)
> goto err_msg;
>
> - xe_uc_gucrc_disable(>->uc);
> - xe_uc_stop_prepare(>->uc);
> - xe_gt_pagefault_reset(gt);
> -
> - err = xe_uc_stop(>->uc);
> - if (err)
> - goto err_out;
> -
> - xe_gt_tlb_invalidation_reset(gt);
> + xe_idle_gt(gt);
>
> err = do_gt_reset(gt);
> if (err)
> diff --git a/drivers/gpu/drm/xe/xe_gt.h b/drivers/gpu/drm/xe/xe_gt.h
> index ed6ea8057e35..77df919199cc 100644
> --- a/drivers/gpu/drm/xe/xe_gt.h
> +++ b/drivers/gpu/drm/xe/xe_gt.h
> @@ -43,6 +43,7 @@ int xe_gt_resume(struct xe_gt *gt);
> void xe_gt_reset_async(struct xe_gt *gt);
> void xe_gt_sanitize(struct xe_gt *gt);
> void xe_gt_remove(struct xe_gt *gt);
> +int xe_idle_gt(struct xe_gt *gt);
>
> /**
> * xe_gt_any_hw_engine_by_reset_domain - scan the list of engines and return the
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index c401d4890386..fcd2a7f66f7b 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -383,6 +383,41 @@ MODULE_DEVICE_TABLE(pci, pciidlist);
>
> #undef INTEL_VGA_DEVICE
>
> +static bool xe_save_pci_state(struct pci_dev *pdev)
> +{
> + struct xe_device *xe = pci_get_drvdata(pdev);
> +
> + if (pci_save_state(pdev))
> + return false;
> +
> + kfree(xe->pci_state);
> +
> + xe->pci_state = pci_store_saved_state(pdev);
> +
> + if (!xe->pci_state) {
> + drm_err(&xe->drm, "Failed to store PCI saved state\n");
> + return false;
> + }
> +
> + return true;
> +}
> +
> +void xe_load_pci_state(struct pci_dev *pdev)
> +{
> + struct xe_device *xe = pci_get_drvdata(pdev);
> + int ret;
> +
> + if (!xe->pci_state)
> + return;
> +
> + ret = pci_load_saved_state(pdev, xe->pci_state);
> + if (!ret) {
> + pci_restore_state(pdev);
> + } else {
> + drm_warn(&xe->drm, "Failed to load PCI state err:%d\n", ret);
> + }
> +}
> +
> /* is device_id present in comma separated list of ids */
> static bool device_id_in_list(u16 device_id, const char *devices, bool negative)
> {
> @@ -688,10 +723,12 @@ static void xe_pci_remove(struct pci_dev *pdev)
>
> xe_device_remove(xe);
> xe_pm_runtime_fini(xe);
> +
> + kfree(xe->pci_state);
> pci_set_drvdata(pdev, NULL);
> }
>
> -static int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> +int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> {
> const struct xe_device_desc *desc = (const void *)ent->driver_data;
> const struct xe_subplatform_desc *subplatform_desc;
> @@ -786,6 +823,9 @@ static int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> drm_dbg(&xe->drm, "d3cold: capable=%s\n",
> str_yes_no(xe->d3cold.capable));
>
> + if (xe_save_pci_state(pdev))
> + pci_restore_state(pdev);
> +
> return 0;
> }
>
> @@ -833,7 +873,7 @@ static int xe_pci_suspend(struct device *dev)
> */
> d3cold_toggle(pdev, D3COLD_ENABLE);
>
> - pci_save_state(pdev);
> + xe_save_pci_state(pdev);
> pci_disable_device(pdev);
>
> return 0;
> @@ -857,6 +897,8 @@ static int xe_pci_resume(struct device *dev)
>
> pci_set_master(pdev);
>
> + xe_load_pci_state(pdev);
> +
> err = xe_pm_resume(pdev_to_xe_device(pdev));
> if (err)
> return err;
> @@ -874,7 +916,7 @@ static int xe_pci_runtime_suspend(struct device *dev)
> if (err)
> return err;
>
> - pci_save_state(pdev);
> + xe_save_pci_state(pdev);
>
> if (xe->d3cold.allowed) {
> d3cold_toggle(pdev, D3COLD_ENABLE);
> @@ -899,7 +941,7 @@ static int xe_pci_runtime_resume(struct device *dev)
> if (err)
> return err;
>
> - pci_restore_state(pdev);
> + xe_load_pci_state(pdev);
>
> if (xe->d3cold.allowed) {
> err = pci_enable_device(pdev);
> @@ -928,6 +970,8 @@ static const struct dev_pm_ops xe_pm_ops = {
> };
> #endif
>
> +extern const struct pci_error_handlers xe_pci_err_handlers;
> +
> static struct pci_driver xe_pci_driver = {
> .name = DRIVER_NAME,
> .id_table = pciidlist,
> @@ -937,6 +981,7 @@ static struct pci_driver xe_pci_driver = {
> #ifdef CONFIG_PM_SLEEP
> .driver.pm = &xe_pm_ops,
> #endif
> + .err_handler = &xe_pci_err_handlers,
> };
>
> int xe_register_pci_driver(void)
> diff --git a/drivers/gpu/drm/xe/xe_pci.h b/drivers/gpu/drm/xe/xe_pci.h
> index 611c1209b14c..9faf5380a09e 100644
> --- a/drivers/gpu/drm/xe/xe_pci.h
> +++ b/drivers/gpu/drm/xe/xe_pci.h
> @@ -6,7 +6,11 @@
> #ifndef _XE_PCI_H_
> #define _XE_PCI_H_
>
> +struct pci_dev;
> +struct pci_device_id;
> +
> int xe_register_pci_driver(void);
> void xe_unregister_pci_driver(void);
> -
> +void xe_load_pci_state(struct pci_dev *pdev);
> +int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
> #endif
> diff --git a/drivers/gpu/drm/xe/xe_pci_err.c b/drivers/gpu/drm/xe/xe_pci_err.c
> new file mode 100644
> index 000000000000..ecc467a9c3af
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_pci_err.c
> @@ -0,0 +1,94 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#include <linux/pci.h>
> +#include <drm/drm_drv.h>
> +
> +#include "xe_device.h"
> +#include "xe_gt.h"
> +#include "xe_gt_printk.h"
> +#include "xe_pci.h"
> +#include "xe_pm.h"
> +
> +/**
> + * xe_pci_reset_prepare - Called when user issued a function level reset
> + * via /sys/bus/pci/devices/.../reset.
> + * @pdev: PCI device struct
> + */
> +static void xe_pci_reset_prepare(struct pci_dev *pdev)
> +{
> + struct xe_device *xe = pci_get_drvdata(pdev);
> + struct xe_gt *gt;
> + int id, err;
> +
> + pci_warn(pdev, "preparing for PCIe FLR reset\n");
> +
> + drm_warn(&xe->drm, "removing device access to userspace\n");
> + drm_dev_unplug(&xe->drm);
> +
> + xe_pm_runtime_get(xe);
> + /* idle the GTs */
> + for_each_gt(gt, xe, id) {
> + err = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> + if (err)
> + goto reset;
> + err = xe_idle_gt(gt);
> + if (err) {
> + xe_gt_err(gt, "failed to idle gt (%pe)\n", ERR_PTR(err));
> + goto reset;
> + }
> +
> + err = xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> + XE_WARN_ON(err);
> + }
> + xe_pm_runtime_put(xe);
perhaps we should only return the ref at the end of the done call?
> +
> +reset:
> + pci_disable_device(pdev);
> +}
> +
> +/**
> + * xe_pci_reset_done - Called when function level reset is done.
> + * @pdev: PCI device struct
> + */
> +static void xe_pci_reset_done(struct pci_dev *pdev)
> +{
> + const struct pci_device_id *ent = pci_match_id(pdev->driver->id_table, pdev);
> + struct xe_device *xe = pci_get_drvdata(pdev);
> +
> + dev_info(&pdev->dev,
> + "PCI device went through FLR, reenabling the device\n");
> +
> + if (pci_enable_device(pdev)) {
> + dev_err(&pdev->dev,
> + "Cannot re-enable PCI device after reset\n");
> + return;
> + }
> + pci_set_master(pdev);
> + xe_load_pci_state(pdev);
> +
> + /*
> + * We want to completely clean the driver and even destroy
> + * the xe private data and reinitialize afresh similar to
> + * probe
> + */
> + pdev->driver->remove(pdev);
> + if (pci_dev_msi_enabled(pdev))
> + pci_free_irq_vectors(pdev);
> +
> + devm_drm_release_action(&xe->drm);
is there any opportunity to have that done at the prepare fn?
or do we really need that to happen after the pci state restoration?
> + pci_disable_device(pdev);
> +
> + /*
> + * if this fails the driver might be in a stale state, only option is
> + * to unbind and rebind
> + */
> + xe_pci_probe(pdev, ent);
> +}
> +
> +const struct pci_error_handlers xe_pci_err_handlers = {
> + .reset_prepare = xe_pci_reset_prepare,
> + .reset_done = xe_pci_reset_done,
I had recently got to this functions while working on the xe_wedged/busted
thing and I was considering something exactly like that.
But you actually got something much simpler then I had thought.
how's the test of that? working reliably?
any IGT?
Thanks for taking care of that.
> +};
> --
> 2.25.1
>
