From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Define a new slave command 'VHOST_USER_SLAVE_FS_IO' for a
client to ask qemu to perform a read/write from an fd directly
to GPA.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
docs/interop/vhost-user.rst | 16 ++++
hw/virtio/trace-events | 6 ++
hw/virtio/vhost-user-fs.c | 95 +++++++++++++++++++++++
hw/virtio/vhost-user.c | 4 +
include/hw/virtio/vhost-user-fs.h | 2 +
subprojects/libvhost-user/libvhost-user.h | 1 +
6 files changed, 124 insertions(+)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 09aee3565d..2fa62ea451 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -1453,6 +1453,22 @@ Slave message types
multiple chunks can be unmapped in one command.
A reply is generated indicating whether unmapping succeeded.
+``VHOST_USER_SLAVE_FS_IO``
+ :id: 9
+ :equivalent ioctl: N/A
+ :slave payload: ``struct VhostUserFSSlaveMsg``
+ :master payload: N/A
+
+ Requests that IO be performed directly from an fd, passed in ancillary
+ data, to guest memory on behalf of the daemon; this is normally for a
+ case where a memory region isn't visible to the daemon. slave payload
+ has flags which determine the direction of IO operation.
+
+ The ``VHOST_USER_FS_FLAG_MAP_R`` flag must be set in the ``flags`` field to
+ read from the file into RAM.
+ The ``VHOST_USER_FS_FLAG_MAP_W`` flag must be set in the ``flags`` field to
+ write to the file from RAM.
+
.. _reply_ack:
VHOST_USER_PROTOCOL_F_REPLY_ACK
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index c62727f879..20557a078e 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -53,6 +53,12 @@ vhost_vdpa_get_features(void *dev, uint64_t features) "dev:
%p features: 0x%"PRI
vhost_vdpa_set_owner(void *dev) "dev: %p"
vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, uint64_t
avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p desc_user_addr:
0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 0x%"PRIx64
+# vhost-user-fs.c
+
+vhost_user_fs_slave_io_loop(const char *name, uint64_t owr, int is_ram, int
is_romd, size_t size) "region %s with internal offset 0x%"PRIx64 " ram=%d
romd=%d mrs.size=%zd"
+vhost_user_fs_slave_io_loop_res(ssize_t transferred) "%zd"
+vhost_user_fs_slave_io_exit(int res, size_t done) "res: %d done: %zd"
+
# virtio.c
virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned
out_num) "elem %p size %zd in_num %u out_num %u"
virtqueue_fill(void *vq, const void *elem, unsigned int len, unsigned int idx)
"vq %p elem %p len %u idx %u"
diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
index 963f694435..5511838f29 100644
--- a/hw/virtio/vhost-user-fs.c
+++ b/hw/virtio/vhost-user-fs.c
@@ -23,6 +23,8 @@
#include "hw/virtio/vhost-user-fs.h"
#include "monitor/monitor.h"
#include "sysemu/sysemu.h"
+#include "exec/address-spaces.h"
+#include "trace.h"
static const int user_feature_bits[] = {
VIRTIO_F_VERSION_1,
@@ -220,6 +222,99 @@ uint64_t vhost_user_fs_slave_unmap(struct vhost_dev *dev,
int message_size,
return (uint64_t)res;
}
+uint64_t vhost_user_fs_slave_io(struct vhost_dev *dev, int message_size,
+ VhostUserFSSlaveMsg *sm, int fd)
+{
+ VHostUserFS *fs = (VHostUserFS *)object_dynamic_cast(OBJECT(dev->vdev),
+ TYPE_VHOST_USER_FS);
+ if (!fs) {
+ error_report("%s: Bad fs ptr", __func__);
+ return (uint64_t)-1;
+ }
+ if (!check_slave_message_entries(sm, message_size)) {
+ return (uint64_t)-1;
+ }
+
+ unsigned int i;
+ int res = 0;
+ size_t done = 0;
+
+ if (fd < 0) {
+ error_report("Bad fd for map");
+ return (uint64_t)-1;
+ }
+
+ for (i = 0; i < sm->count && !res; i++) {
+ VhostUserFSSlaveMsgEntry *e = &sm->entries[i];
+ if (e->len == 0) {
+ continue;
+ }
+
+ size_t len = e->len;
+ uint64_t fd_offset = e->fd_offset;
+ hwaddr gpa = e->c_offset;
+
+ while (len && !res) {
+ hwaddr xlat, xlat_len;
+ bool is_write = e->flags & VHOST_USER_FS_FLAG_MAP_W;
+ MemoryRegion *mr = address_space_translate(dev->vdev->dma_as, gpa,
+ &xlat, &xlat_len,
+ is_write,
+ MEMTXATTRS_UNSPECIFIED);
+ if (!mr || !xlat_len) {
+ error_report("No guest region found for 0x%" HWADDR_PRIx, gpa);
+ res = -EFAULT;
+ break;
+ }
+
+ trace_vhost_user_fs_slave_io_loop(mr->name,
+ (uint64_t)xlat,
+ memory_region_is_ram(mr),
+ memory_region_is_romd(mr),
+ (size_t)xlat_len);
+
+ void *hostptr = qemu_map_ram_ptr(mr->ram_block,
+ xlat);
+ ssize_t transferred;
+ if (e->flags & VHOST_USER_FS_FLAG_MAP_R) {
+ /* Read from file into RAM */
+ if (mr->readonly) {
+ res = -EFAULT;
+ break;
+ }
+ transferred = pread(fd, hostptr, xlat_len, fd_offset);
+ } else if (e->flags & VHOST_USER_FS_FLAG_MAP_W) {
+ /* Write into file from RAM */
+ transferred = pwrite(fd, hostptr, xlat_len, fd_offset);
+ } else {
+ transferred = EINVAL;
+ }
+
+ trace_vhost_user_fs_slave_io_loop_res(transferred);
+ if (transferred < 0) {
+ res = -errno;
+ break;
+ }
+ if (!transferred) {
+ /* EOF */
+ break;
+ }
+
+ done += transferred;
+ fd_offset += transferred;
+ gpa += transferred;
+ len -= transferred;
+ }
+ }
+ close(fd);
+
+ trace_vhost_user_fs_slave_io_exit(res, done);
+ if (res < 0) {
+ return (uint64_t)res;
+ }
+ return (uint64_t)done;
+}
+
static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
{
VHostUserFS *fs = VHOST_USER_FS(vdev);
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index ad9170f8dc..b9699586ae 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -138,6 +138,7 @@ typedef enum VhostUserSlaveRequest {
VHOST_USER_SLAVE_VRING_ERR = 5,
VHOST_USER_SLAVE_FS_MAP = 6,
VHOST_USER_SLAVE_FS_UNMAP = 7,
+ VHOST_USER_SLAVE_FS_IO = 8,
VHOST_USER_SLAVE_MAX
} VhostUserSlaveRequest;
@@ -1562,6 +1563,9 @@ static gboolean slave_read(QIOChannel *ioc, GIOCondition
condition,
case VHOST_USER_SLAVE_FS_UNMAP:
ret = vhost_user_fs_slave_unmap(dev, hdr.size, &payload.fs);
break;
+ case VHOST_USER_SLAVE_FS_IO:
+ ret = vhost_user_fs_slave_io(dev, hdr.size, &payload.fs, fd[0]);
+ break;
#endif
default:
error_report("Received unexpected msg type: %d.", hdr.request);
diff --git a/include/hw/virtio/vhost-user-fs.h
b/include/hw/virtio/vhost-user-fs.h
index 0766f17548..2931164e23 100644
--- a/include/hw/virtio/vhost-user-fs.h
+++ b/include/hw/virtio/vhost-user-fs.h
@@ -78,5 +78,7 @@ uint64_t vhost_user_fs_slave_map(struct vhost_dev *dev, int
message_size,
VhostUserFSSlaveMsg *sm, int fd);
uint64_t vhost_user_fs_slave_unmap(struct vhost_dev *dev, int message_size,
VhostUserFSSlaveMsg *sm);
+uint64_t vhost_user_fs_slave_io(struct vhost_dev *dev, int message_size,
+ VhostUserFSSlaveMsg *sm, int fd);
#endif /* _QEMU_VHOST_USER_FS_H */
diff --git a/subprojects/libvhost-user/libvhost-user.h
b/subprojects/libvhost-user/libvhost-user.h
index a98c5f5c11..42b0833c4b 100644
--- a/subprojects/libvhost-user/libvhost-user.h
+++ b/subprojects/libvhost-user/libvhost-user.h
@@ -121,6 +121,7 @@ typedef enum VhostUserSlaveRequest {
VHOST_USER_SLAVE_VRING_ERR = 5,
VHOST_USER_SLAVE_FS_MAP = 6,
VHOST_USER_SLAVE_FS_UNMAP = 7,
+ VHOST_USER_SLAVE_FS_IO = 8,
VHOST_USER_SLAVE_MAX
} VhostUserSlaveRequest;
--
2.31.1
