xref: /linux/drivers/gpu/drm/xe/xe_pci_sriov.c (revision bde5d79d00255db609fe9d859eef8c7b6d38b137)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2023-2024 Intel Corporation
4  */
5 
6 #include "xe_assert.h"
7 #include "xe_device.h"
8 #include "xe_gt_sriov_pf_config.h"
9 #include "xe_gt_sriov_pf_control.h"
10 #include "xe_pci_sriov.h"
11 #include "xe_pm.h"
12 #include "xe_sriov.h"
13 #include "xe_sriov_pf_helpers.h"
14 #include "xe_sriov_printk.h"
15 
16 static int pf_needs_provisioning(struct xe_gt *gt, unsigned int num_vfs)
17 {
18 	unsigned int n;
19 
20 	for (n = 1; n <= num_vfs; n++)
21 		if (!xe_gt_sriov_pf_config_is_empty(gt, n))
22 			return false;
23 
24 	return true;
25 }
26 
27 static int pf_provision_vfs(struct xe_device *xe, unsigned int num_vfs)
28 {
29 	struct xe_gt *gt;
30 	unsigned int id;
31 	int result = 0, err;
32 
33 	for_each_gt(gt, xe, id) {
34 		if (!pf_needs_provisioning(gt, num_vfs))
35 			continue;
36 		err = xe_gt_sriov_pf_config_set_fair(gt, VFID(1), num_vfs);
37 		result = result ?: err;
38 	}
39 
40 	return result;
41 }
42 
43 static void pf_unprovision_vfs(struct xe_device *xe, unsigned int num_vfs)
44 {
45 	struct xe_gt *gt;
46 	unsigned int id;
47 	unsigned int n;
48 
49 	for_each_gt(gt, xe, id)
50 		for (n = 1; n <= num_vfs; n++)
51 			xe_gt_sriov_pf_config_release(gt, n, true);
52 }
53 
54 static void pf_reset_vfs(struct xe_device *xe, unsigned int num_vfs)
55 {
56 	struct xe_gt *gt;
57 	unsigned int id;
58 	unsigned int n;
59 
60 	for_each_gt(gt, xe, id)
61 		for (n = 1; n <= num_vfs; n++)
62 			xe_gt_sriov_pf_control_trigger_flr(gt, n);
63 }
64 
65 static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
66 {
67 	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
68 	int total_vfs = xe_sriov_pf_get_totalvfs(xe);
69 	int err;
70 
71 	xe_assert(xe, IS_SRIOV_PF(xe));
72 	xe_assert(xe, num_vfs > 0);
73 	xe_assert(xe, num_vfs <= total_vfs);
74 	xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));
75 
76 	/*
77 	 * We must hold additional reference to the runtime PM to keep PF in D0
78 	 * during VFs lifetime, as our VFs do not implement the PM capability.
79 	 *
80 	 * With PF being in D0 state, all VFs will also behave as in D0 state.
81 	 * This will also keep GuC alive with all VFs' configurations.
82 	 *
83 	 * We will release this additional PM reference in pf_disable_vfs().
84 	 */
85 	xe_pm_runtime_get_noresume(xe);
86 
87 	err = pf_provision_vfs(xe, num_vfs);
88 	if (err < 0)
89 		goto failed;
90 
91 	err = pci_enable_sriov(pdev, num_vfs);
92 	if (err < 0)
93 		goto failed;
94 
95 	xe_sriov_info(xe, "Enabled %u of %u VF%s\n",
96 		      num_vfs, total_vfs, str_plural(total_vfs));
97 	return num_vfs;
98 
99 failed:
100 	pf_unprovision_vfs(xe, num_vfs);
101 	xe_pm_runtime_put(xe);
102 
103 	xe_sriov_notice(xe, "Failed to enable %u VF%s (%pe)\n",
104 			num_vfs, str_plural(num_vfs), ERR_PTR(err));
105 	return err;
106 }
107 
108 static int pf_disable_vfs(struct xe_device *xe)
109 {
110 	struct device *dev = xe->drm.dev;
111 	struct pci_dev *pdev = to_pci_dev(dev);
112 	u16 num_vfs = pci_num_vf(pdev);
113 
114 	xe_assert(xe, IS_SRIOV_PF(xe));
115 	xe_sriov_dbg(xe, "disabling %u VF%s\n", num_vfs, str_plural(num_vfs));
116 
117 	if (!num_vfs)
118 		return 0;
119 
120 	pci_disable_sriov(pdev);
121 
122 	pf_reset_vfs(xe, num_vfs);
123 
124 	pf_unprovision_vfs(xe, num_vfs);
125 
126 	/* not needed anymore - see pf_enable_vfs() */
127 	xe_pm_runtime_put(xe);
128 
129 	xe_sriov_info(xe, "Disabled %u VF%s\n", num_vfs, str_plural(num_vfs));
130 	return 0;
131 }
132 
133 /**
134  * xe_pci_sriov_configure - Configure SR-IOV (enable/disable VFs).
135  * @pdev: the &pci_dev
136  * @num_vfs: number of VFs to enable or zero to disable all VFs
137  *
138  * This is the Xe implementation of struct pci_driver.sriov_configure callback.
139  *
140  * This callback will be called by the PCI subsystem to enable or disable SR-IOV
141  * Virtual Functions (VFs) as requested by the used via the PCI sysfs interface.
142  *
143  * Return: number of configured VFs or a negative error code on failure.
144  */
145 int xe_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
146 {
147 	struct xe_device *xe = pdev_to_xe_device(pdev);
148 	int ret;
149 
150 	if (!IS_SRIOV_PF(xe))
151 		return -ENODEV;
152 
153 	if (num_vfs < 0)
154 		return -EINVAL;
155 
156 	if (num_vfs > xe_sriov_pf_get_totalvfs(xe))
157 		return -ERANGE;
158 
159 	if (num_vfs && pci_num_vf(pdev))
160 		return -EBUSY;
161 
162 	xe_pm_runtime_get(xe);
163 	if (num_vfs > 0)
164 		ret = pf_enable_vfs(xe, num_vfs);
165 	else
166 		ret = pf_disable_vfs(xe);
167 	xe_pm_runtime_put(xe);
168 
169 	return ret;
170 }
171