1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
4  */
5 
6 #include <linux/vfio.h>
7 #include <linux/slab.h>
8 #include <linux/types.h>
9 #include <linux/eventfd.h>
10 #include <linux/msi.h>
11 #include <linux/interrupt.h>
12 
13 #include "linux/cdx/cdx_bus.h"
14 #include "private.h"
15 
vfio_cdx_msihandler(int irq_no,void * arg)16 static irqreturn_t vfio_cdx_msihandler(int irq_no, void *arg)
17 {
18 	struct eventfd_ctx *trigger = arg;
19 
20 	eventfd_signal(trigger);
21 	return IRQ_HANDLED;
22 }
23 
vfio_cdx_msi_enable(struct vfio_cdx_device * vdev,int nvec)24 static int vfio_cdx_msi_enable(struct vfio_cdx_device *vdev, int nvec)
25 {
26 	struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
27 	struct device *dev = vdev->vdev.dev;
28 	int msi_idx, ret;
29 
30 	vdev->cdx_irqs = kcalloc(nvec, sizeof(struct vfio_cdx_irq), GFP_KERNEL);
31 	if (!vdev->cdx_irqs)
32 		return -ENOMEM;
33 
34 	ret = cdx_enable_msi(cdx_dev);
35 	if (ret) {
36 		kfree(vdev->cdx_irqs);
37 		return ret;
38 	}
39 
40 	/* Allocate cdx MSIs */
41 	ret = msi_domain_alloc_irqs(dev, MSI_DEFAULT_DOMAIN, nvec);
42 	if (ret) {
43 		cdx_disable_msi(cdx_dev);
44 		kfree(vdev->cdx_irqs);
45 		return ret;
46 	}
47 
48 	for (msi_idx = 0; msi_idx < nvec; msi_idx++)
49 		vdev->cdx_irqs[msi_idx].irq_no = msi_get_virq(dev, msi_idx);
50 
51 	vdev->msi_count = nvec;
52 	vdev->config_msi = 1;
53 
54 	return 0;
55 }
56 
vfio_cdx_msi_set_vector_signal(struct vfio_cdx_device * vdev,int vector,int fd)57 static int vfio_cdx_msi_set_vector_signal(struct vfio_cdx_device *vdev,
58 					  int vector, int fd)
59 {
60 	struct eventfd_ctx *trigger;
61 	int irq_no, ret;
62 
63 	if (vector < 0 || vector >= vdev->msi_count)
64 		return -EINVAL;
65 
66 	irq_no = vdev->cdx_irqs[vector].irq_no;
67 
68 	if (vdev->cdx_irqs[vector].trigger) {
69 		free_irq(irq_no, vdev->cdx_irqs[vector].trigger);
70 		kfree(vdev->cdx_irqs[vector].name);
71 		eventfd_ctx_put(vdev->cdx_irqs[vector].trigger);
72 		vdev->cdx_irqs[vector].trigger = NULL;
73 	}
74 
75 	if (fd < 0)
76 		return 0;
77 
78 	vdev->cdx_irqs[vector].name = kasprintf(GFP_KERNEL, "vfio-msi[%d](%s)",
79 						vector, dev_name(vdev->vdev.dev));
80 	if (!vdev->cdx_irqs[vector].name)
81 		return -ENOMEM;
82 
83 	trigger = eventfd_ctx_fdget(fd);
84 	if (IS_ERR(trigger)) {
85 		kfree(vdev->cdx_irqs[vector].name);
86 		return PTR_ERR(trigger);
87 	}
88 
89 	ret = request_irq(irq_no, vfio_cdx_msihandler, 0,
90 			  vdev->cdx_irqs[vector].name, trigger);
91 	if (ret) {
92 		kfree(vdev->cdx_irqs[vector].name);
93 		eventfd_ctx_put(trigger);
94 		return ret;
95 	}
96 
97 	vdev->cdx_irqs[vector].trigger = trigger;
98 
99 	return 0;
100 }
101 
vfio_cdx_msi_set_block(struct vfio_cdx_device * vdev,unsigned int start,unsigned int count,int32_t * fds)102 static int vfio_cdx_msi_set_block(struct vfio_cdx_device *vdev,
103 				  unsigned int start, unsigned int count,
104 				  int32_t *fds)
105 {
106 	int i, j, ret = 0;
107 
108 	if (start >= vdev->msi_count || start + count > vdev->msi_count)
109 		return -EINVAL;
110 
111 	for (i = 0, j = start; i < count && !ret; i++, j++) {
112 		int fd = fds ? fds[i] : -1;
113 
114 		ret = vfio_cdx_msi_set_vector_signal(vdev, j, fd);
115 	}
116 
117 	if (ret) {
118 		for (--j; j >= (int)start; j--)
119 			vfio_cdx_msi_set_vector_signal(vdev, j, -1);
120 	}
121 
122 	return ret;
123 }
124 
vfio_cdx_msi_disable(struct vfio_cdx_device * vdev)125 static void vfio_cdx_msi_disable(struct vfio_cdx_device *vdev)
126 {
127 	struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
128 	struct device *dev = vdev->vdev.dev;
129 
130 	vfio_cdx_msi_set_block(vdev, 0, vdev->msi_count, NULL);
131 
132 	if (!vdev->config_msi)
133 		return;
134 
135 	msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
136 	cdx_disable_msi(cdx_dev);
137 	kfree(vdev->cdx_irqs);
138 
139 	vdev->cdx_irqs = NULL;
140 	vdev->msi_count = 0;
141 	vdev->config_msi = 0;
142 }
143 
vfio_cdx_set_msi_trigger(struct vfio_cdx_device * vdev,unsigned int index,unsigned int start,unsigned int count,u32 flags,void * data)144 static int vfio_cdx_set_msi_trigger(struct vfio_cdx_device *vdev,
145 				    unsigned int index, unsigned int start,
146 				    unsigned int count, u32 flags,
147 				    void *data)
148 {
149 	struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
150 	int i;
151 
152 	if (start + count > cdx_dev->num_msi)
153 		return -EINVAL;
154 
155 	if (!count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
156 		vfio_cdx_msi_disable(vdev);
157 		return 0;
158 	}
159 
160 	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
161 		s32 *fds = data;
162 		int ret;
163 
164 		if (vdev->config_msi)
165 			return vfio_cdx_msi_set_block(vdev, start, count,
166 						  fds);
167 		ret = vfio_cdx_msi_enable(vdev, cdx_dev->num_msi);
168 		if (ret)
169 			return ret;
170 
171 		ret = vfio_cdx_msi_set_block(vdev, start, count, fds);
172 		if (ret)
173 			vfio_cdx_msi_disable(vdev);
174 
175 		return ret;
176 	}
177 
178 	for (i = start; i < start + count; i++) {
179 		if (!vdev->cdx_irqs[i].trigger)
180 			continue;
181 		if (flags & VFIO_IRQ_SET_DATA_NONE) {
182 			eventfd_signal(vdev->cdx_irqs[i].trigger);
183 		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
184 			u8 *bools = data;
185 
186 			if (bools[i - start])
187 				eventfd_signal(vdev->cdx_irqs[i].trigger);
188 		}
189 	}
190 
191 	return 0;
192 }
193 
vfio_cdx_set_irqs_ioctl(struct vfio_cdx_device * vdev,u32 flags,unsigned int index,unsigned int start,unsigned int count,void * data)194 int vfio_cdx_set_irqs_ioctl(struct vfio_cdx_device *vdev,
195 			    u32 flags, unsigned int index,
196 			    unsigned int start, unsigned int count,
197 			    void *data)
198 {
199 	if (flags & VFIO_IRQ_SET_ACTION_TRIGGER)
200 		return vfio_cdx_set_msi_trigger(vdev, index, start,
201 			  count, flags, data);
202 	else
203 		return -EINVAL;
204 }
205 
206 /* Free All IRQs for the given device */
vfio_cdx_irqs_cleanup(struct vfio_cdx_device * vdev)207 void vfio_cdx_irqs_cleanup(struct vfio_cdx_device *vdev)
208 {
209 	/*
210 	 * Device does not support any interrupt or the interrupts
211 	 * were not configured
212 	 */
213 	if (!vdev->cdx_irqs)
214 		return;
215 
216 	vfio_cdx_set_msi_trigger(vdev, 0, 0, 0, VFIO_IRQ_SET_DATA_NONE, NULL);
217 }
218