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mstsirkinmstsirkin
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Revert "virtio_pci: use shared interrupts for virtqueues"
This reverts commit 07ec514. Conflicts: drivers/virtio/virtio_pci_common.c Unfortunately the idea does not work with threadirqs as more than 32 queues can then map to a single interrupts. Further, the cleanup seems to be one of the changes that broke hybernation for some users. We are still not sure why but revert helps. This reverts the cleanup changes but keeps the affinity support. Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
1 parent 2008c15 commit 0b0f9dc

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2 files changed

+148
-112
lines changed

2 files changed

+148
-112
lines changed

‎drivers/virtio/virtio_pci_common.c

+134-110
Original file line numberDiff line numberDiff line change
@@ -33,8 +33,10 @@ void vp_synchronize_vectors(struct virtio_device *vdev)
3333
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
3434
int i;
3535

36-
synchronize_irq(pci_irq_vector(vp_dev->pci_dev, 0));
37-
for (i = 1; i < vp_dev->msix_vectors; i++)
36+
if (vp_dev->intx_enabled)
37+
synchronize_irq(vp_dev->pci_dev->irq);
38+
39+
for (i = 0; i < vp_dev->msix_vectors; ++i)
3840
synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
3941
}
4042

@@ -97,10 +99,79 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
9799
return vp_vring_interrupt(irq, opaque);
98100
}
99101

100-
static void vp_remove_vqs(struct virtio_device *vdev)
102+
static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
103+
bool per_vq_vectors, struct irq_affinity *desc)
104+
{
105+
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
106+
const char *name = dev_name(&vp_dev->vdev.dev);
107+
unsigned i, v;
108+
int err = -ENOMEM;
109+
110+
vp_dev->msix_vectors = nvectors;
111+
112+
vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names,
113+
GFP_KERNEL);
114+
if (!vp_dev->msix_names)
115+
goto error;
116+
vp_dev->msix_affinity_masks
117+
= kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks,
118+
GFP_KERNEL);
119+
if (!vp_dev->msix_affinity_masks)
120+
goto error;
121+
for (i = 0; i < nvectors; ++i)
122+
if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
123+
GFP_KERNEL))
124+
goto error;
125+
126+
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
127+
nvectors, PCI_IRQ_MSIX |
128+
(desc ? PCI_IRQ_AFFINITY : 0),
129+
desc);
130+
if (err < 0)
131+
goto error;
132+
vp_dev->msix_enabled = 1;
133+
134+
/* Set the vector used for configuration */
135+
v = vp_dev->msix_used_vectors;
136+
snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
137+
"%s-config", name);
138+
err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
139+
vp_config_changed, 0, vp_dev->msix_names[v],
140+
vp_dev);
141+
if (err)
142+
goto error;
143+
++vp_dev->msix_used_vectors;
144+
145+
v = vp_dev->config_vector(vp_dev, v);
146+
/* Verify we had enough resources to assign the vector */
147+
if (v == VIRTIO_MSI_NO_VECTOR) {
148+
err = -EBUSY;
149+
goto error;
150+
}
151+
152+
if (!per_vq_vectors) {
153+
/* Shared vector for all VQs */
154+
v = vp_dev->msix_used_vectors;
155+
snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
156+
"%s-virtqueues", name);
157+
err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
158+
vp_vring_interrupt, 0, vp_dev->msix_names[v],
159+
vp_dev);
160+
if (err)
161+
goto error;
162+
++vp_dev->msix_used_vectors;
163+
}
164+
return 0;
165+
error:
166+
return err;
167+
}
168+
169+
/* the config->del_vqs() implementation */
170+
void vp_del_vqs(struct virtio_device *vdev)
101171
{
102172
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
103173
struct virtqueue *vq, *n;
174+
int i;
104175

105176
list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
106177
if (vp_dev->msix_vector_map) {
@@ -112,33 +183,35 @@ static void vp_remove_vqs(struct virtio_device *vdev)
112183
}
113184
vp_dev->del_vq(vq);
114185
}
115-
}
116186

117-
/* the config->del_vqs() implementation */
118-
void vp_del_vqs(struct virtio_device *vdev)
119-
{
120-
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
121-
int i;
122-
123-
if (WARN_ON_ONCE(list_empty_careful(&vdev->vqs)))
124-
return;
187+
if (vp_dev->intx_enabled) {
188+
free_irq(vp_dev->pci_dev->irq, vp_dev);
189+
vp_dev->intx_enabled = 0;
190+
}
125191

126-
vp_remove_vqs(vdev);
192+
for (i = 0; i < vp_dev->msix_used_vectors; ++i)
193+
free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
127194

128-
if (vp_dev->msix_enabled) {
129-
for (i = 0; i < vp_dev->msix_vectors; i++)
195+
for (i = 0; i < vp_dev->msix_vectors; i++)
196+
if (vp_dev->msix_affinity_masks[i])
130197
free_cpumask_var(vp_dev->msix_affinity_masks[i]);
131198

199+
if (vp_dev->msix_enabled) {
132200
/* Disable the vector used for configuration */
133201
vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
134202

135-
kfree(vp_dev->msix_affinity_masks);
136-
kfree(vp_dev->msix_names);
137-
kfree(vp_dev->msix_vector_map);
203+
pci_free_irq_vectors(vp_dev->pci_dev);
204+
vp_dev->msix_enabled = 0;
138205
}
139206

140-
free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
141-
pci_free_irq_vectors(vp_dev->pci_dev);
207+
vp_dev->msix_vectors = 0;
208+
vp_dev->msix_used_vectors = 0;
209+
kfree(vp_dev->msix_names);
210+
vp_dev->msix_names = NULL;
211+
kfree(vp_dev->msix_affinity_masks);
212+
vp_dev->msix_affinity_masks = NULL;
213+
kfree(vp_dev->msix_vector_map);
214+
vp_dev->msix_vector_map = NULL;
142215
}
143216

144217
static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
@@ -147,128 +220,80 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
147220
struct irq_affinity *desc)
148221
{
149222
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
150-
const char *name = dev_name(&vp_dev->vdev.dev);
151-
int i, err = -ENOMEM, allocated_vectors, nvectors;
152-
unsigned flags = PCI_IRQ_MSIX;
153223
u16 msix_vec;
154-
155-
if (desc) {
156-
flags |= PCI_IRQ_AFFINITY;
157-
desc->pre_vectors++; /* virtio config vector */
158-
}
159-
160-
nvectors = 1;
161-
for (i = 0; i < nvqs; i++)
162-
if (callbacks[i])
163-
nvectors++;
224+
int i, err, nvectors, allocated_vectors;
164225

165226
if (per_vq_vectors) {
166-
err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
167-
nvectors, flags, desc);
227+
/* Best option: one for change interrupt, one per vq. */
228+
nvectors = 1;
229+
for (i = 0; i < nvqs; ++i)
230+
if (callbacks[i])
231+
++nvectors;
168232
} else {
169-
err = pci_alloc_irq_vectors(vp_dev->pci_dev, 2, 2,
170-
PCI_IRQ_MSIX);
171-
}
172-
if (err < 0)
173-
return err;
174-
175-
vp_dev->msix_vectors = nvectors;
176-
vp_dev->msix_names = kmalloc_array(nvectors,
177-
sizeof(*vp_dev->msix_names), GFP_KERNEL);
178-
if (!vp_dev->msix_names)
179-
goto out_free_irq_vectors;
180-
181-
vp_dev->msix_affinity_masks = kcalloc(nvectors,
182-
sizeof(*vp_dev->msix_affinity_masks), GFP_KERNEL);
183-
if (!vp_dev->msix_affinity_masks)
184-
goto out_free_msix_names;
185-
186-
for (i = 0; i < nvectors; ++i) {
187-
if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
188-
GFP_KERNEL))
189-
goto out_free_msix_affinity_masks;
233+
/* Second best: one for change, shared for all vqs. */
234+
nvectors = 2;
190235
}
191236

192-
/* Set the vector used for configuration */
193-
snprintf(vp_dev->msix_names[0], sizeof(*vp_dev->msix_names),
194-
"%s-config", name);
195-
err = request_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_config_changed,
196-
0, vp_dev->msix_names[0], vp_dev);
237+
err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors,
238+
per_vq_vectors ? desc : NULL);
197239
if (err)
198-
goto out_free_irq_vectors;
240+
goto error_find;
199241

200-
/* Verify we had enough resources to assign the vector */
201-
if (vp_dev->config_vector(vp_dev, 0) == VIRTIO_MSI_NO_VECTOR) {
202-
err = -EBUSY;
203-
goto out_free_config_irq;
242+
if (per_vq_vectors) {
243+
vp_dev->msix_vector_map = kmalloc_array(nvqs,
244+
sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
245+
if (!vp_dev->msix_vector_map)
246+
goto error_find;
204247
}
205248

206-
vp_dev->msix_vector_map = kmalloc_array(nvqs,
207-
sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
208-
if (!vp_dev->msix_vector_map)
209-
goto out_disable_config_irq;
210-
211-
allocated_vectors = 1; /* vector 0 is the config interrupt */
249+
allocated_vectors = vp_dev->msix_used_vectors;
212250
for (i = 0; i < nvqs; ++i) {
213251
if (!names[i]) {
214252
vqs[i] = NULL;
215253
continue;
216254
}
217255

218-
if (callbacks[i])
219-
msix_vec = allocated_vectors;
220-
else
256+
if (!callbacks[i])
221257
msix_vec = VIRTIO_MSI_NO_VECTOR;
222-
258+
else if (per_vq_vectors)
259+
msix_vec = allocated_vectors++;
260+
else
261+
msix_vec = VP_MSIX_VQ_VECTOR;
223262
vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
224263
msix_vec);
225264
if (IS_ERR(vqs[i])) {
226265
err = PTR_ERR(vqs[i]);
227-
goto out_remove_vqs;
266+
goto error_find;
228267
}
229268

269+
if (!per_vq_vectors)
270+
continue;
271+
230272
if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
231273
vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
232274
continue;
233275
}
234276

235-
snprintf(vp_dev->msix_names[i + 1],
236-
sizeof(*vp_dev->msix_names), "%s-%s",
277+
/* allocate per-vq irq if available and necessary */
278+
snprintf(vp_dev->msix_names[msix_vec],
279+
sizeof *vp_dev->msix_names,
280+
"%s-%s",
237281
dev_name(&vp_dev->vdev.dev), names[i]);
238282
err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
239-
vring_interrupt, IRQF_SHARED,
240-
vp_dev->msix_names[i + 1], vqs[i]);
283+
vring_interrupt, 0,
284+
vp_dev->msix_names[msix_vec],
285+
vqs[i]);
241286
if (err) {
242287
/* don't free this irq on error */
243288
vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
244-
goto out_remove_vqs;
289+
goto error_find;
245290
}
246291
vp_dev->msix_vector_map[i] = msix_vec;
247-
248-
if (per_vq_vectors)
249-
allocated_vectors++;
250292
}
251-
252-
vp_dev->msix_enabled = 1;
253293
return 0;
254294

255-
out_remove_vqs:
256-
vp_remove_vqs(vdev);
257-
kfree(vp_dev->msix_vector_map);
258-
out_disable_config_irq:
259-
vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
260-
out_free_config_irq:
261-
free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
262-
out_free_msix_affinity_masks:
263-
for (i = 0; i < nvectors; i++) {
264-
if (vp_dev->msix_affinity_masks[i])
265-
free_cpumask_var(vp_dev->msix_affinity_masks[i]);
266-
}
267-
kfree(vp_dev->msix_affinity_masks);
268-
out_free_msix_names:
269-
kfree(vp_dev->msix_names);
270-
out_free_irq_vectors:
271-
pci_free_irq_vectors(vp_dev->pci_dev);
295+
error_find:
296+
vp_del_vqs(vdev);
272297
return err;
273298
}
274299

@@ -282,8 +307,9 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
282307
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
283308
dev_name(&vdev->dev), vp_dev);
284309
if (err)
285-
return err;
310+
goto out_del_vqs;
286311

312+
vp_dev->intx_enabled = 1;
287313
for (i = 0; i < nvqs; ++i) {
288314
if (!names[i]) {
289315
vqs[i] = NULL;
@@ -293,15 +319,13 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
293319
VIRTIO_MSI_NO_VECTOR);
294320
if (IS_ERR(vqs[i])) {
295321
err = PTR_ERR(vqs[i]);
296-
goto out_remove_vqs;
322+
goto out_del_vqs;
297323
}
298324
}
299325

300326
return 0;
301-
302-
out_remove_vqs:
303-
vp_remove_vqs(vdev);
304-
free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
327+
out_del_vqs:
328+
vp_del_vqs(vdev);
305329
return err;
306330
}
307331

‎drivers/virtio/virtio_pci_common.h

+14-2
Original file line numberDiff line numberDiff line change
@@ -66,12 +66,16 @@ struct virtio_pci_device {
6666

6767
/* MSI-X support */
6868
int msix_enabled;
69+
int intx_enabled;
6970
cpumask_var_t *msix_affinity_masks;
7071
/* Name strings for interrupts. This size should be enough,
7172
* and I'm too lazy to allocate each name separately. */
7273
char (*msix_names)[256];
73-
/* Total Number of MSI-X vectors (including per-VQ ones). */
74-
int msix_vectors;
74+
/* Number of available vectors */
75+
unsigned msix_vectors;
76+
/* Vectors allocated, excluding per-vq vectors if any */
77+
unsigned msix_used_vectors;
78+
7579
/* Map of per-VQ MSI-X vectors, may be NULL */
7680
unsigned *msix_vector_map;
7781

@@ -85,6 +89,14 @@ struct virtio_pci_device {
8589
u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
8690
};
8791

92+
/* Constants for MSI-X */
93+
/* Use first vector for configuration changes, second and the rest for
94+
* virtqueues Thus, we need at least 2 vectors for MSI. */
95+
enum {
96+
VP_MSIX_CONFIG_VECTOR = 0,
97+
VP_MSIX_VQ_VECTOR = 1,
98+
};
99+
88100
/* Convert a generic virtio device to our structure */
89101
static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
90102
{

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