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virtio: Implement get_shm_region for MMIO transport 

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@intel.com>
Cc: kvm@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
zero-sugar-mainline-defconfig
Sebastien Boeuf 2020-08-19 18:19:43 -04:00 committed by Miklos Szeredi
parent 0dd4ff93f4
commit 38e895487a
2 changed files with 42 additions and 0 deletions
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31
drivers/virtio/virtio_mmio.c
View File

@ -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,
};

11
include/uapi/linux/virtio_mmio.h
View File

@ -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