linux/drivers/gpu/drm/xe/xe_pci_sriov.c

// SPDX-License-Identifier: MIT
/*
 * Copyright © 2023-2024 Intel Corporation
 */

#include <linux/bitops.h>
#include <linux/pci.h>

#include "regs/xe_bars.h"
#include "xe_assert.h"
#include "xe_device.h"
#include "xe_gt_sriov_pf_config.h"
#include "xe_gt_sriov_pf_control.h"
#include "xe_gt_sriov_printk.h"
#include "xe_guc_engine_activity.h"
#include "xe_pci_sriov.h"
#include "xe_pm.h"
#include "xe_sriov.h"
#include "xe_sriov_pf.h"
#include "xe_sriov_pf_control.h"
#include "xe_sriov_pf_helpers.h"
#include "xe_sriov_pf_provision.h"
#include "xe_sriov_pf_sysfs.h"
#include "xe_sriov_printk.h"

static void pf_reset_vfs(struct xe_device *xe, unsigned int num_vfs)
{
	unsigned int n;

	for (n = 1; n <= num_vfs; n++)
		xe_sriov_pf_control_reset_vf(xe, n);
}

static void pf_link_vfs(struct xe_device *xe, int num_vfs)
{
	struct pci_dev *pdev_pf = to_pci_dev(xe->drm.dev);
	struct device_link *link;
	struct pci_dev *pdev_vf;
	unsigned int n;

	/*
	 * When both PF and VF devices are enabled on the host, during system
	 * resume they are resuming in parallel.
	 *
	 * But PF has to complete the provision of VF first to allow any VFs to
	 * successfully resume.
	 *
	 * Create a parent-child device link between PF and VF devices that will
	 * enforce correct resume order.
	 */
	for (n = 1; n <= num_vfs; n++) {
		pdev_vf = xe_pci_sriov_get_vf_pdev(pdev_pf, n);

		/* unlikely, something weird is happening, abort */
		if (!pdev_vf) {
			xe_sriov_err(xe, "Cannot find VF%u device, aborting link%s creation!\n",
				     n, str_plural(num_vfs));
			break;
		}

		link = device_link_add(&pdev_vf->dev, &pdev_pf->dev,
				       DL_FLAG_AUTOREMOVE_CONSUMER);
		/* unlikely and harmless, continue with other VFs */
		if (!link)
			xe_sriov_notice(xe, "Failed linking VF%u\n", n);

		pci_dev_put(pdev_vf);
	}
}

static void pf_engine_activity_stats(struct xe_device *xe, unsigned int num_vfs, bool enable)
{
	struct xe_gt *gt;
	unsigned int id;
	int ret = 0;

	for_each_gt(gt, xe, id) {
		ret = xe_guc_engine_activity_function_stats(&gt->uc.guc, num_vfs, enable);
		if (ret)
			xe_gt_sriov_info(gt, "Failed to %s engine activity function stats (%pe)\n",
					 str_enable_disable(enable), ERR_PTR(ret));
	}
}

static int resize_vf_vram_bar(struct xe_device *xe, int num_vfs)
{
	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
	u32 sizes;

	sizes = pci_iov_vf_bar_get_sizes(pdev, VF_LMEM_BAR, num_vfs);
	if (!sizes)
		return 0;

	return pci_iov_vf_bar_set_size(pdev, VF_LMEM_BAR, __fls(sizes));
}

static int pf_prepare_vfs_enabling(struct xe_device *xe)
{
	xe_assert(xe, IS_SRIOV_PF(xe));
	/* make sure we are not locked-down by other components */
	return xe_sriov_pf_arm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL);
}

static void pf_finish_vfs_enabling(struct xe_device *xe)
{
	xe_assert(xe, IS_SRIOV_PF(xe));
	/* allow other components to lockdown VFs enabling */
	xe_sriov_pf_disarm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL);
}

static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
{
	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
	int total_vfs = xe_sriov_pf_get_totalvfs(xe);
	int err;

	xe_assert(xe, IS_SRIOV_PF(xe));
	xe_assert(xe, num_vfs > 0);
	xe_assert(xe, num_vfs <= total_vfs);
	xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));

	err = xe_sriov_pf_wait_ready(xe);
	if (err)
		goto out;

	err = pf_prepare_vfs_enabling(xe);
	if (err)
		goto out;

	/*
	 * We must hold additional reference to the runtime PM to keep PF in D0
	 * during VFs lifetime, as our VFs do not implement the PM capability.
	 *
	 * With PF being in D0 state, all VFs will also behave as in D0 state.
	 * This will also keep GuC alive with all VFs' configurations.
	 *
	 * We will release this additional PM reference in pf_disable_vfs().
	 */
	xe_pm_runtime_get_noresume(xe);

	err = xe_sriov_pf_provision_vfs(xe, num_vfs);
	if (err < 0)
		goto failed;

	if (IS_DGFX(xe)) {
		err = resize_vf_vram_bar(xe, num_vfs);
		if (err)
			xe_sriov_info(xe, "Failed to set VF LMEM BAR size: %d\n", err);
	}

	err = pci_enable_sriov(pdev, num_vfs);
	if (err < 0)
		goto failed;

	pf_link_vfs(xe, num_vfs);

	xe_sriov_info(xe, "Enabled %u of %u VF%s\n",
		      num_vfs, total_vfs, str_plural(total_vfs));

	xe_sriov_pf_sysfs_link_vfs(xe, num_vfs);

	pf_engine_activity_stats(xe, num_vfs, true);

	return num_vfs;

failed:
	xe_sriov_pf_unprovision_vfs(xe, num_vfs);
	xe_pm_runtime_put(xe);
	pf_finish_vfs_enabling(xe);
out:
	xe_sriov_notice(xe, "Failed to enable %u VF%s (%pe)\n",
			num_vfs, str_plural(num_vfs), ERR_PTR(err));
	return err;
}

static int pf_disable_vfs(struct xe_device *xe)
{
	struct device *dev = xe->drm.dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	u16 num_vfs = pci_num_vf(pdev);

	xe_assert(xe, IS_SRIOV_PF(xe));
	xe_sriov_dbg(xe, "disabling %u VF%s\n", num_vfs, str_plural(num_vfs));

	if (!num_vfs)
		return 0;

	pf_engine_activity_stats(xe, num_vfs, false);

	xe_sriov_pf_sysfs_unlink_vfs(xe, num_vfs);

	pci_disable_sriov(pdev);

	pf_reset_vfs(xe, num_vfs);

	xe_sriov_pf_unprovision_vfs(xe, num_vfs);

	/* not needed anymore - see pf_enable_vfs() */
	xe_pm_runtime_put(xe);

	pf_finish_vfs_enabling(xe);

	xe_sriov_info(xe, "Disabled %u VF%s\n", num_vfs, str_plural(num_vfs));
	return 0;
}

/**
 * xe_pci_sriov_configure - Configure SR-IOV (enable/disable VFs).
 * @pdev: the &pci_dev
 * @num_vfs: number of VFs to enable or zero to disable all VFs
 *
 * This is the Xe implementation of struct pci_driver.sriov_configure callback.
 *
 * This callback will be called by the PCI subsystem to enable or disable SR-IOV
 * Virtual Functions (VFs) as requested by the used via the PCI sysfs interface.
 *
 * Return: number of configured VFs or a negative error code on failure.
 */
int xe_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
{
	struct xe_device *xe = pdev_to_xe_device(pdev);

	if (!IS_SRIOV_PF(xe))
		return -ENODEV;

	if (num_vfs < 0)
		return -EINVAL;

	if (num_vfs > xe_sriov_pf_get_totalvfs(xe))
		return -ERANGE;

	if (num_vfs && pci_num_vf(pdev))
		return -EBUSY;

	guard(xe_pm_runtime)(xe);
	if (num_vfs > 0)
		return pf_enable_vfs(xe, num_vfs);
	else
		return pf_disable_vfs(xe);
}

/**
 * xe_pci_sriov_get_vf_pdev() - Lookup the VF's PCI device using the VF identifier.
 * @pdev: the PF's &pci_dev
 * @vfid: VF identifier (1-based)
 *
 * The caller must decrement the reference count by calling pci_dev_put().
 *
 * Return: the VF's &pci_dev or NULL if the VF device was not found.
 */
struct pci_dev *xe_pci_sriov_get_vf_pdev(struct pci_dev *pdev, unsigned int vfid)
{
	struct xe_device *xe = pdev_to_xe_device(pdev);

	xe_assert(xe, dev_is_pf(&pdev->dev));
	xe_assert(xe, vfid);
	xe_assert(xe, vfid <= pci_sriov_get_totalvfs(pdev));

	return pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
					   pdev->bus->number,
					   pci_iov_virtfn_devfn(pdev, vfid - 1));
}