From 87e7bf1450c9f6bd0927f63ebc0fe2d12e8bc83d Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 12 Mar 2015 12:56:43 +1030 Subject: [PATCH] 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: Michael S. Tsirkin Signed-off-by: Rusty Russell --- drivers/virtio/virtio_mmio.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index cad569890908..9c877d2375a5 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -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, -- 2.11.4.GIT