[RFC 2/2] drm/xe/FLR: Support PCIe FLR
Aravind Iddamsetty
aravind.iddamsetty at linux.intel.com
Thu Mar 21 10:45:23 UTC 2024
On 21/03/24 02:22, Rodrigo Vivi wrote:
> 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 at intel.com>
>> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>> Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty at linux.intel.com>
>> ---
>> 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?
it looks to be that the runtime ref is already taken before reset_prepare
is invoked and released only after below done call.
drivers/pci/pci-sysfs.c:
reset_store {
pm_runtime_get_sync(dev);
result = pci_reset_function(pdev);
pm_runtime_put(dev);
}
>
>> +
>> +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?
ideally we better do it here, as the device might be in a non functional state
in reset prepare and in remove path we touch the device which might result in
unwanted failures. it is safe to do here as we know the reset is done and we can clear the stale state.
>
>> + 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?
I had tested manually for couple of times it worked, except for some warnings
the output of which I pasted in cover letter. I'm yet to develop any IGT.
>
> Thanks for taking care of that.
Thank you!
Regards,
Aravind.
>
>> +};
>> --
>> 2.25.1
>>
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