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[PATCH 16/24] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PATCH 16/24] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO |
Date: |
Tue, 9 Feb 2021 19:02:16 +0000 |
From: "Dr. David Alan Gilbert" <dgilbert@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 <dgilbert@redhat.com>
---
docs/interop/vhost-user.rst | 11 +++
hw/virtio/trace-events | 6 ++
hw/virtio/vhost-user-fs.c | 84 +++++++++++++++++++++++
hw/virtio/vhost-user.c | 4 ++
include/hw/virtio/vhost-user-fs.h | 2 +
subprojects/libvhost-user/libvhost-user.h | 1 +
6 files changed, 108 insertions(+)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 1deedd3407..821712f4a2 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -1452,6 +1452,17 @@ 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: fd + n * (offset + address + len)
+ :master payload: N/A
+
+ Requests that the QEMU performs IO directly from an fd 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.
+
.. _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 5f2fca4d82..357bc1d04e 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"
/*
* The powerpc kernel code expects the memory to be accessible during
@@ -155,6 +157,88 @@ uint64_t vhost_user_fs_slave_unmap(struct vhost_dev *dev,
return (uint64_t)res;
}
+uint64_t vhost_user_fs_slave_io(struct vhost_dev *dev, VhostUserFSSlaveMsg *sm,
+ int fd)
+{
+ VHostUserFS *fs = VHOST_USER_FS(dev->vdev);
+ if (!fs) {
+ /* Shouldn't happen - but seen it in error paths */
+ error_report("Bad fs ptr");
+ 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 < VHOST_USER_FS_SLAVE_ENTRIES && !res; i++) {
+ if (sm->len[i] == 0) {
+ continue;
+ }
+
+ size_t len = sm->len[i];
+ hwaddr gpa = sm->c_offset[i];
+
+ while (len && !res) {
+ MemoryRegionSection mrs = memory_region_find(get_system_memory(),
+ gpa, len);
+ size_t mrs_size = (size_t)int128_get64(mrs.size);
+
+ if (!mrs_size) {
+ error_report("No guest region found for 0x%" HWADDR_PRIx, gpa);
+ res = -EFAULT;
+ break;
+ }
+
+ trace_vhost_user_fs_slave_io_loop(mrs.mr->name,
+ (uint64_t)mrs.offset_within_region,
+ memory_region_is_ram(mrs.mr),
+ memory_region_is_romd(mrs.mr),
+ (size_t)mrs_size);
+
+ void *hostptr = qemu_map_ram_ptr(mrs.mr->ram_block,
+ mrs.offset_within_region);
+ ssize_t transferred;
+ if (sm->flags[i] & VHOST_USER_FS_FLAG_MAP_R) {
+ /* Read from file into RAM */
+ if (mrs.mr->readonly) {
+ res = -EFAULT;
+ break;
+ }
+ transferred = pread(fd, hostptr, mrs_size, sm->fd_offset[i]);
+ } else {
+ /* Write into file from RAM */
+ assert((sm->flags[i] & VHOST_USER_FS_FLAG_MAP_W));
+ transferred = pwrite(fd, hostptr, mrs_size, sm->fd_offset[i]);
+ }
+ trace_vhost_user_fs_slave_io_loop_res(transferred);
+ if (transferred < 0) {
+ res = -errno;
+ break;
+ }
+ if (!transferred) {
+ /* EOF */
+ break;
+ }
+
+ done += 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 21e40ff91a..0bc83c2714 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -137,6 +137,7 @@ 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;
@@ -1485,6 +1486,9 @@ static void slave_read(void *opaque)
case VHOST_USER_SLAVE_FS_UNMAP:
ret = vhost_user_fs_slave_unmap(dev, &payload.fs);
break;
+ case VHOST_USER_SLAVE_FS_IO:
+ ret = vhost_user_fs_slave_io(dev, &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 25e14ab17a..ffd3165c29 100644
--- a/include/hw/virtio/vhost-user-fs.h
+++ b/include/hw/virtio/vhost-user-fs.h
@@ -69,5 +69,7 @@ uint64_t vhost_user_fs_slave_map(struct vhost_dev *dev,
VhostUserFSSlaveMsg *sm,
int fd);
uint64_t vhost_user_fs_slave_unmap(struct vhost_dev *dev,
VhostUserFSSlaveMsg *sm);
+uint64_t vhost_user_fs_slave_io(struct vhost_dev *dev, 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 150b1121cc..a398148ed9 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;
--
2.29.2
- [PATCH 15/24] DAX: virtiofsd: Perform an unmap on destroy, (continued)
- [PATCH 15/24] DAX: virtiofsd: Perform an unmap on destroy, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 19/24] DAX/unmap virtiofsd: Route unmappable reads, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 18/24] DAX/unmap virtiofsd: Parse unmappable elements, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 17/24] DAX/unmap virtiofsd: Add wrappers for VHOST_USER_SLAVE_FS_IO, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 20/24] DAX/unmap virtiofsd: route unmappable write to slave command, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 21/24] DAX:virtiofsd: implement FUSE_INIT map_alignment field, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 22/24] vhost-user-fs: Extend VhostUserFSSlaveMsg to pass additional info, Dr. David Alan Gilbert (git), 2021/02/09
- [PATCH 16/24] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO,
Dr. David Alan Gilbert (git) <=
- [PATCH 23/24] vhost-user-fs: Implement drop CAP_FSETID functionality, Dr. David Alan Gilbert (git), 2021/02/09
[PATCH 24/24] virtiofsd: Ask qemu to drop CAP_FSETID if client asked for it, Dr. David Alan Gilbert (git), 2021/02/09