Vivek Goyal
2020-Aug-19 22:19 UTC
[PATCH v3 05/18] virtio: Implement get_shm_region for MMIO transport
From: Sebastien Boeuf <sebastien.boeuf at 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.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf at intel.com>
Cc: kvm at vger.kernel.org
Cc: virtualization at lists.linux-foundation.org
Cc: "Michael S. Tsirkin" <mst at redhat.com>
---
drivers/virtio/virtio_mmio.c | 31 +++++++++++++++++++++++++++++++
include/uapi/linux/virtio_mmio.h | 11 +++++++++++
2 files changed, 42 insertions(+)
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 627ac0487494..238383ff1064 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -498,6 +498,36 @@ 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;
+
+ /* 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,
@@ -510,6 +540,7 @@ static const struct virtio_config_ops virtio_mmio_config_ops
= {
.get_features = vm_get_features,
.finalize_features = vm_finalize_features,
.bus_name = vm_bus_name,
+ .get_shm_region = vm_get_shm_region,
};
diff --git a/include/uapi/linux/virtio_mmio.h b/include/uapi/linux/virtio_mmio.h
index c4b09689ab64..0650f91bea6c 100644
--- a/include/uapi/linux/virtio_mmio.h
+++ b/include/uapi/linux/virtio_mmio.h
@@ -122,6 +122,17 @@
#define VIRTIO_MMIO_QUEUE_USED_LOW 0x0a0
#define VIRTIO_MMIO_QUEUE_USED_HIGH 0x0a4
+/* Shared memory region id */
+#define VIRTIO_MMIO_SHM_SEL 0x0ac
+
+/* Shared memory region length, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_LEN_LOW 0x0b0
+#define VIRTIO_MMIO_SHM_LEN_HIGH 0x0b4
+
+/* Shared memory region base address, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_BASE_LOW 0x0b8
+#define VIRTIO_MMIO_SHM_BASE_HIGH 0x0bc
+
/* Configuration atomicity value */
#define VIRTIO_MMIO_CONFIG_GENERATION 0x0fc
--
2.25.4