Use the newly introduced SHM_PAGE_SIZE register to read the page size
and store it into virtio_shm_region.
Signed-off-by: Sergio Lopez <slp@xxxxxxxxxx>
---
drivers/virtio/virtio_mmio.c | 13 ++++++++++++-
include/uapi/linux/virtio_mmio.h | 3 +++
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index cd0a0407659517e6a318b117ba67258c59f1f983..92590c77901bee453d8c1a1ac60ad9cca90d1b59 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -537,6 +537,7 @@ 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);
+ u16 page_size = 0;
u64 len, addr;
/* Select the region we're interested in */
@@ -560,7 +561,17 @@ static bool vm_get_shm_region(struct virtio_device *vdev,
region->addr = addr;
- region->page_size = 4096 >> 12;
+ /* If supported by the device transport, read the region page size */
+ if (__virtio_test_bit(vdev, VIRTIO_F_SHM_PAGE_SIZE))
+ page_size = (u16) readl(vm_dev->base + VIRTIO_MMIO_SHM_PAGE_SIZE);
+
+ /* For backwards compatibility, if the device didn't specify a
+ * page size, assume it to be 4096.
+ */
+ if (page_size == 0)
+ page_size = 4096 >> 12;
+
+ region->page_size = page_size;
return true;
}
diff --git a/include/uapi/linux/virtio_mmio.h b/include/uapi/linux/virtio_mmio.h
index 0650f91bea6c70f935764070d825d181a2379afb..c5a1cdad5a1c9bc954d7facfd8c05e2acbb28e96 100644
--- a/include/uapi/linux/virtio_mmio.h
+++ b/include/uapi/linux/virtio_mmio.h
@@ -133,6 +133,9 @@
#define VIRTIO_MMIO_SHM_BASE_LOW 0x0b8
#define VIRTIO_MMIO_SHM_BASE_HIGH 0x0bc
+/* Shared memory region page size, in format PAGE_SIZE >> 12 */
+#define VIRTIO_MMIO_SHM_PAGE_SIZE 0x0c4
+
/* Configuration atomicity value */
#define VIRTIO_MMIO_CONFIG_GENERATION 0x0fc
--
2.48.1
