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Subject: [PATCH 03/16] virtio: implement "v1.0" bit.
From: Rusty Russell <rusty@rustcorp.com.au> This is a test to see what it looks like. I store a bool in the device structure: our test_bit() uses volatile, so the code doesn't get eliminated even if gcc sees both sides are the same :( Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> --- drivers/virtio/virtio.c | 7 +++++++ include/linux/virtio.h | 8 ++++++++ include/uapi/linux/virtio_config.h | 3 +++ 3 files changed, 18 insertions(+) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index e342692..179412d 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -133,6 +133,13 @@ static int virtio_dev_probe(struct device *_d) if (device_features & (1ULL << i)) dev->features |= (1ULL << i); + /* Version 1.0 compliant devices set the VIRTIO_F_VERSION_1 bit */ + if (device_features & (1ULL << VIRTIO_F_VERSION_1)) { + dev->legacy = false; + dev->features |= (1ULL << VIRTIO_F_VERSION_1); + } else + dev->legacy = true; + dev->config->finalize_features(dev); err = drv->probe(dev); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 838a395..2c3cbd4 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -9,6 +9,7 @@ #include <linux/mod_devicetable.h> #include <linux/gfp.h> #include <linux/vringh.h> +#include <uapi/linux/virtio_config.h> /** * virtqueue - a queue to register buffers for sending or receiving. @@ -76,6 +77,7 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq); /** * virtio_device - representation of a device using virtio * @index: unique position on the virtio bus + * @legacy: set if this is a pre-v1.0 device. * @dev: underlying device. * @id: the device type identification (used to match it with a driver). * @config: the configuration ops for this device. @@ -86,6 +88,7 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq); */ struct virtio_device { int index; + bool legacy; struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; @@ -100,6 +103,11 @@ static inline struct virtio_device *dev_to_virtio(struct device *_dev) return container_of(_dev, struct virtio_device, dev); } +static inline bool virtio_device_legacy(const struct virtio_device *dev) +{ + return dev->legacy; +} + int register_virtio_device(struct virtio_device *dev); void unregister_virtio_device(struct virtio_device *dev); diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h index 3ce768c..80e7381 100644 --- a/include/uapi/linux/virtio_config.h +++ b/include/uapi/linux/virtio_config.h @@ -54,4 +54,7 @@ /* Can the device handle any descriptor layout? */ #define VIRTIO_F_ANY_LAYOUT 27 +/* v1.0 compliant. */ +#define VIRTIO_F_VERSION_1 32 + #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */ -- 1.8.1.2
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