drivers/gpu/drm/xe/xe_sriov_pf.c

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

#include <drm/drm_managed.h>

#include "xe_assert.h"
#include "xe_device.h"
#include "xe_module.h"
#include "xe_sriov.h"
#include "xe_sriov_pf.h"
#include "xe_sriov_printk.h"

static unsigned int wanted_max_vfs(struct xe_device *xe)
{
	return xe_modparam.max_vfs;
}

static int pf_reduce_totalvfs(struct xe_device *xe, int limit)
{
	struct device *dev = xe->drm.dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	int err;

	err = pci_sriov_set_totalvfs(pdev, limit);
	if (err)
		xe_sriov_notice(xe, "Failed to set number of VFs to %d (%pe)\n",
				limit, ERR_PTR(err));
	return err;
}

static bool pf_continue_as_native(struct xe_device *xe, const char *why)
{
	xe_sriov_dbg(xe, "%s, continuing as native\n", why);
	pf_reduce_totalvfs(xe, 0);
	return false;
}

/**
 * xe_sriov_pf_readiness - Check if PF functionality can be enabled.
 * @xe: the &xe_device to check
 *
 * This function is called as part of the SR-IOV probe to validate if all
 * PF prerequisites are satisfied and we can continue with enabling PF mode.
 *
 * Return: true if the PF mode can be turned on.
 */
bool xe_sriov_pf_readiness(struct xe_device *xe)
{
	struct device *dev = xe->drm.dev;
	struct pci_dev *pdev = to_pci_dev(dev);
	int totalvfs = pci_sriov_get_totalvfs(pdev);
	int newlimit = min_t(u16, wanted_max_vfs(xe), totalvfs);

	xe_assert(xe, totalvfs <= U16_MAX);

	if (!dev_is_pf(dev))
		return false;

	if (!xe_device_uc_enabled(xe))
		return pf_continue_as_native(xe, "Guc submission disabled");

	if (!newlimit)
		return pf_continue_as_native(xe, "all VFs disabled");

	pf_reduce_totalvfs(xe, newlimit);

	xe->sriov.pf.device_total_vfs = totalvfs;
	xe->sriov.pf.driver_max_vfs = newlimit;

	return true;
}

/**
 * xe_sriov_pf_init_early - Initialize SR-IOV PF specific data.
 * @xe: the &xe_device to initialize
 *
 * Return: 0 on success or a negative error code on failure.
 */
int xe_sriov_pf_init_early(struct xe_device *xe)
{
	xe_assert(xe, IS_SRIOV_PF(xe));

	return drmm_mutex_init(&xe->drm, &xe->sriov.pf.master_lock);
}

/**
 * xe_sriov_pf_print_vfs_summary - Print SR-IOV PF information.
 * @xe: the &xe_device to print info from
 * @p: the &drm_printer
 *
 * Print SR-IOV PF related information into provided DRM printer.
 */
void xe_sriov_pf_print_vfs_summary(struct xe_device *xe, struct drm_printer *p)
{
	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);

	xe_assert(xe, IS_SRIOV_PF(xe));

	drm_printf(p, "total: %u\n", xe->sriov.pf.device_total_vfs);
	drm_printf(p, "supported: %u\n", xe->sriov.pf.driver_max_vfs);
	drm_printf(p, "enabled: %u\n", pci_num_vf(pdev));
}