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Commit 87e7bf14 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Rusty Russell
Browse files

virtio_mmio: generation support 



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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 71e4b8bf

drivers/virtio/virtio_mmio.c

+11 −0
Original line number Diff line number Diff line
@@ -174,6 +174,16 @@ static void vm_set(struct virtio_device *vdev, unsigned offset, 
		writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);

}



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);
@@ -440,6 +450,7 @@ 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,

	.set_status	= vm_set_status,

	.reset		= vm_reset,