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429711aec2
linux/drivers/vhost
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Jason Wang 429711aec2 vhost: switch to use new message format 
We use to have message like:

struct vhost_msg {
	int type;
	union {
		struct vhost_iotlb_msg iotlb;
		__u8 padding[64];
	};
};

Unfortunately, there will be a hole of 32bit in 64bit machine because
of the alignment. This leads a different formats between 32bit API and
64bit API. What's more it will break 32bit program running on 64bit
machine.

So fixing this by introducing a new message type with an explicit
32bit reserved field after type like:

struct vhost_msg_v2 {
	__u32 type;
	__u32 reserved;
	union {
		struct vhost_iotlb_msg iotlb;
		__u8 padding[64];
	};
};

We will have a consistent ABI after switching to use this. To enable
this capability, introduce a new ioctl (VHOST_SET_BAKCEND_FEATURE) for
userspace to enable this feature (VHOST_BACKEND_F_IOTLB_V2).

Fixes: 6b1e6cc785 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-06 10:41:04 -07:00
..
Kconfig tap: tap as an independent module 2017-02-11 20:59:41 -05:00
Kconfig.vringh
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
net.c vhost: switch to use new message format 2018-08-06 10:41:04 -07:00
scsi.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
test.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
test.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vhost.c vhost: switch to use new message format 2018-08-06 10:41:04 -07:00
vhost.h vhost: switch to use new message format 2018-08-06 10:41:04 -07:00
vringh.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
vsock.c fw_cfg, vhost: features fixes 2018-04-06 19:21:41 -07:00