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SubjectRe: [PATCH 05/19] virtio: Implement get_shm_region for MMIO transport
On Wed, 21 Aug 2019 13:57:06 -0400
Vivek Goyal <vgoyal@redhat.com> wrote:

> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
>
> On MMIO a new set of registers is defined for finding SHM
> regions. Add their definitions and use them to find the region.
>
> Cc: kvm@vger.kernel.org
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> ---
> drivers/virtio/virtio_mmio.c | 32 ++++++++++++++++++++++++++++++++
> include/uapi/linux/virtio_mmio.h | 11 +++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index e09edb5c5e06..5c07985c8cb8 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -500,6 +500,37 @@ static const char *vm_bus_name(struct virtio_device *vdev)
> return vm_dev->pdev->name;
> }
>
> +static bool vm_get_shm_region(struct virtio_device *vdev,
> + struct virtio_shm_region *region, u8 id)
> +{
> + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
> + u64 len, addr;
> +
> + /* Select the region we're interested in */
> + writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
> +
> + /* Read the region size */
> + len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
> + len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
> +
> + region->len = len;
> +
> + /* Check if region length is -1. If that's the case, the shared memory
> + * region does not exist and there is no need to proceed further.
> + */
> + if (len == ~(u64)0) {
> + return false;
> + }

I think the curly braces should be dropped here.

> +
> + /* Read the region base address */
> + addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
> + addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
> +
> + region->addr = addr;
> +
> + return true;
> +}
> +
> static const struct virtio_config_ops virtio_mmio_config_ops = {
> .get = vm_get,
> .set = vm_set,

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

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