virtio_mmio currently lacks generation support which
makes multi-byte field access racy.
Fix by getting the value at offset 0xfc for version 2
devices. Nothing we can do for version 1, so return
generation id 0.
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
Pawel, you mentioned you have a working virtio 1.0
hypervisor, can you pls confirm this works correctly?
drivers/virtio/virtio_mmio.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 0375456..69b2e4d 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -237,6 +237,16 @@ static void vm_set(struct virtio_device *vdev, unsigned
offset,
}
}
+static u32 vm_generation(struct virtio_device *vdev)
+{
+ struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+
+ if (vm_dev->version == 1)
+ return 0;
+ else
+ return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
+}
+
static u8 vm_get_status(struct virtio_device *vdev)
{
struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
@@ -503,6 +513,8 @@ static const char *vm_bus_name(struct virtio_device *vdev)
static const struct virtio_config_ops virtio_mmio_config_ops = {
.get = vm_get,
.set = vm_set,
+ .generation = vm_generation,
+ .get_status = vm_get_status,
.get_status = vm_get_status,
.set_status = vm_set_status,
.reset = vm_reset,
--
MST
On Thu, Mar 05, 2015 at 11:09:42PM +0100, Michael S. Tsirkin wrote:> virtio_mmio currently lacks generation support which > makes multi-byte field access racy. > Fix by getting the value at offset 0xfc for version 2 > devices. Nothing we can do for version 1, so return > generation id 0. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > > Pawel, you mentioned you have a working virtio 1.0 > hypervisor, can you pls confirm this works correctly?Same here - can you ack pls?> drivers/virtio/virtio_mmio.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c > index 0375456..69b2e4d 100644 > --- a/drivers/virtio/virtio_mmio.c > +++ b/drivers/virtio/virtio_mmio.c > @@ -237,6 +237,16 @@ static void vm_set(struct virtio_device *vdev, unsigned offset, > } > } > > +static u32 vm_generation(struct virtio_device *vdev) > +{ > + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); > + > + if (vm_dev->version == 1) > + return 0; > + else > + return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION); > +} > + > static u8 vm_get_status(struct virtio_device *vdev) > { > struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); > @@ -503,6 +513,8 @@ static const char *vm_bus_name(struct virtio_device *vdev) > static const struct virtio_config_ops virtio_mmio_config_ops = { > .get = vm_get, > .set = vm_set, > + .generation = vm_generation, > + .get_status = vm_get_status, > .get_status = vm_get_status, > .set_status = vm_set_status, > .reset = vm_reset, > -- > MST
"Michael S. Tsirkin" <mst at redhat.com> writes:> virtio_mmio currently lacks generation support which > makes multi-byte field access racy. > Fix by getting the value at offset 0xfc for version 2 > devices. Nothing we can do for version 1, so return > generation id 0. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > > Pawel, you mentioned you have a working virtio 1.0 > hypervisor, can you pls confirm this works correctly?I've applied this one, but fixed it to compile:> drivers/virtio/virtio_mmio.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c > index 0375456..69b2e4d 100644 > --- a/drivers/virtio/virtio_mmio.c > +++ b/drivers/virtio/virtio_mmio.c > @@ -237,6 +237,16 @@ static void vm_set(struct virtio_device *vdev, unsigned offset, > } > } > > +static u32 vm_generation(struct virtio_device *vdev) > +{ > + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); > + > + if (vm_dev->version == 1) > + return 0; > + else > + return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION); > +} > + > static u8 vm_get_status(struct virtio_device *vdev) > { > struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); > @@ -503,6 +513,8 @@ static const char *vm_bus_name(struct virtio_device *vdev) > static const struct virtio_config_ops virtio_mmio_config_ops = { > .get = vm_get, > .set = vm_set, > + .generation = vm_generation, > + .get_status = vm_get_status, > .get_status = vm_get_status,See the double-assingment of get_status? Thanks, Rusty. PS. Sorry, that *does* actually compile. I wish it didn't though...
On Thu, 2015-03-12 at 02:07 +0000, Rusty Russell wrote:> "Michael S. Tsirkin" <mst at redhat.com> writes: > > virtio_mmio currently lacks generation support which > > makes multi-byte field access racy. > > Fix by getting the value at offset 0xfc for version 2 > > devices. Nothing we can do for version 1, so return > > generation id 0. > > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > > > Pawel, you mentioned you have a working virtio 1.0 > > hypervisor, can you pls confirm this works correctly?Again, belated Acked-by: Pawel Moll <pawel.moll at arm.com> although not yet tested-by... Pawe?