diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2025-12-29 18:27:21 -0500 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2026-01-08 09:54:27 -0500 |
| commit | bd2b617c49820a38cefcf512c6d56d30deb59aa9 (patch) | |
| tree | 908c11710a6f0d45502383aecedae3f6348e3794 | |
| parent | 2678369e8efe0c5ac71adb49fbc2c240a222e44d (diff) | |
virtio-rng: fix DMA alignment for data buffer
The data buffer in struct virtrng_info is used for DMA_FROM_DEVICE via
virtqueue_add_inbuf() and shares cachelines with the adjacent
CPU-written fields (data_avail, data_idx).
The device writing to the DMA buffer and the CPU writing to adjacent
fields could corrupt each other's data on non-cache-coherent platforms.
Add __dma_from_device_group_begin()/end() annotations to place these
in distinct cache lines.
Message-ID: <157a63b6324d1f1307ddd4faa3b62a8b90a79423.1767601130.git.mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | drivers/char/hw_random/virtio-rng.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index dd998f4fe4f2..eb80a031c7be 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -11,6 +11,7 @@ #include <linux/spinlock.h> #include <linux/virtio.h> #include <linux/virtio_rng.h> +#include <linux/dma-mapping.h> #include <linux/module.h> #include <linux/slab.h> @@ -28,11 +29,13 @@ struct virtrng_info { unsigned int data_avail; unsigned int data_idx; /* minimal size returned by rng_buffer_size() */ + __dma_from_device_group_begin(); #if SMP_CACHE_BYTES < 32 u8 data[32]; #else u8 data[SMP_CACHE_BYTES]; #endif + __dma_from_device_group_end(); }; static void random_recv_done(struct virtqueue *vq) |