* [PATCH] virtio_pci: add module param to force legacy mode
@ 2015-01-15 15:56 ` Michael S. Tsirkin
0 siblings, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2015-01-15 15:56 UTC (permalink / raw)
To: linux-kernel; +Cc: Rusty Russell, virtualization
If set, try legacy interface first, modern one if that fails. Useful to
work around device/driver bugs, and for compatibility testing.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/virtio/virtio_pci_common.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 20c7638..0f87b99 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -19,6 +19,14 @@
#include "virtio_pci_common.h"
+static bool force_legacy = false;
+
+#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
+module_param(force_legacy, bool, 0444);
+MODULE_PARM_DESC(force_legacy,
+ "Force legacy mode for transitional virtio 1 devices");
+#endif
+
/* wait for pending irq handlers */
void vp_synchronize_vectors(struct virtio_device *vdev)
{
@@ -505,13 +513,24 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
if (rc)
goto err_request_regions;
- rc = virtio_pci_modern_probe(vp_dev);
- if (rc != -ENODEV)
- return rc;
+ if (force_legacy) {
+ rc = virtio_pci_legacy_probe(vp_dev);
+ /* Also try modern mode if we can't map BAR0 (no IO space). */
+ if (rc != -ENODEV && rc != -ENOMEM)
+ return rc;
- rc = virtio_pci_legacy_probe(vp_dev);
- if (rc)
- goto err_probe;
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ } else {
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc != -ENODEV)
+ return rc;
+
+ rc = virtio_pci_legacy_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ }
pci_set_master(pci_dev);
--
MST
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] virtio_pci: add module param to force legacy mode
@ 2015-01-15 15:56 ` Michael S. Tsirkin
0 siblings, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2015-01-15 15:56 UTC (permalink / raw)
To: linux-kernel; +Cc: virtualization
If set, try legacy interface first, modern one if that fails. Useful to
work around device/driver bugs, and for compatibility testing.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/virtio/virtio_pci_common.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 20c7638..0f87b99 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -19,6 +19,14 @@
#include "virtio_pci_common.h"
+static bool force_legacy = false;
+
+#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY)
+module_param(force_legacy, bool, 0444);
+MODULE_PARM_DESC(force_legacy,
+ "Force legacy mode for transitional virtio 1 devices");
+#endif
+
/* wait for pending irq handlers */
void vp_synchronize_vectors(struct virtio_device *vdev)
{
@@ -505,13 +513,24 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
if (rc)
goto err_request_regions;
- rc = virtio_pci_modern_probe(vp_dev);
- if (rc != -ENODEV)
- return rc;
+ if (force_legacy) {
+ rc = virtio_pci_legacy_probe(vp_dev);
+ /* Also try modern mode if we can't map BAR0 (no IO space). */
+ if (rc != -ENODEV && rc != -ENOMEM)
+ return rc;
- rc = virtio_pci_legacy_probe(vp_dev);
- if (rc)
- goto err_probe;
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ } else {
+ rc = virtio_pci_modern_probe(vp_dev);
+ if (rc != -ENODEV)
+ return rc;
+
+ rc = virtio_pci_legacy_probe(vp_dev);
+ if (rc)
+ goto err_probe;
+ }
pci_set_master(pci_dev);
--
MST
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] virtio_pci: add module param to force legacy mode
2015-01-15 15:56 ` Michael S. Tsirkin
(?)
@ 2015-01-19 5:53 ` Rusty Russell
-1 siblings, 0 replies; 3+ messages in thread
From: Rusty Russell @ 2015-01-19 5:53 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel; +Cc: virtualization
"Michael S. Tsirkin" <mst@redhat.com> writes:
> If set, try legacy interface first, modern one if that fails. Useful to
> work around device/driver bugs, and for compatibility testing.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Thanks, I've applied all these to virtio-next.
Cheers!
Rusty.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-01-19 7:42 UTC | newest]
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2015-01-15 15:56 [PATCH] virtio_pci: add module param to force legacy mode Michael S. Tsirkin
2015-01-15 15:56 ` Michael S. Tsirkin
2015-01-19 5:53 ` Rusty Russell
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