| Message ID | 20210209190224.62827-17-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtiofs dax patches | expand |
On Tue, Feb 09, 2021 at 07:02:16PM +0000, Dr. David Alan Gilbert (git) wrote: > 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) Please clarify the payload representation. This is not enough for someone to implement the spec. > + :master payload: N/A > + > + Requests that the QEMU performs IO directly from an fd to guest memory To avoid naming a particular VMM: s/the QEMU performs IO/IO be performed/ > + 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. Please document the payload flags in the spec. > + > .. _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; > + } Same pointer casting issue as with map/unmap. > + > + 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 there is a vIOMMU then the vhost-user device backend should be restricted to just areas of guest RAM that are mapped. I think this can be achieved by using the vhost-user-fs device's address space instead of get_system_memory(). For example, virtio_pci_get_dma_as(). > + > + 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) { The flag name is specific to map requests but it's shared with the IO request. Perhaps rename the flags? > + /* 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)); The vhost-user device backend must not be able to crash the VMM. Please use an if statement and fail the request if the flags are invalid instead of assert(). > + 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; Is gpa += transferred missing so that this loop can handle crossing MemoryRegion boundaries? sm->fd_offset[i] also needs to be put into a local variable and incremented by transferred each time around the loop.
* Stefan Hajnoczi (stefanha@redhat.com) wrote: > On Tue, Feb 09, 2021 at 07:02:16PM +0000, Dr. David Alan Gilbert (git) wrote: > > 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) > > Please clarify the payload representation. This is not enough for > someone to implement the spec. Done: ) + :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. + .. > > + :master payload: N/A > > + > > + Requests that the QEMU performs IO directly from an fd to guest memory > > To avoid naming a particular VMM: > > s/the QEMU performs IO/IO be performed/ > > > + 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. > > Please document the payload flags in the spec. + 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 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; > > + } > > Same pointer casting issue as with map/unmap. Done > > + > > + 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 there is a vIOMMU then the vhost-user device backend should be > restricted to just areas of guest RAM that are mapped. I think this can > be achieved by using the vhost-user-fs device's address space instead of > get_system_memory(). For example, virtio_pci_get_dma_as(). Written but not yet tested, as : 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 (!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) { > > The flag name is specific to map requests but it's shared with the IO > request. Perhaps rename the flags? They're both read/write's; do you have a preferred alternative? > > + /* 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)); > > The vhost-user device backend must not be able to crash the VMM. Please > use an if statement and fail the request if the flags are invalid > instead of assert(). Done > > + 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; > > Is gpa += transferred missing so that this loop can handle crossing > MemoryRegion boundaries? > > sm->fd_offset[i] also needs to be put into a local variable and > incremented by transferred each time around the loop. Hmm yes, both of those are right; this obviously needs more testing, especially across boundaries. Dave
On Tue, Mar 16, 2021 at 07:59:59PM +0000, Dr. David Alan Gilbert wrote: > * Stefan Hajnoczi (stefanha@redhat.com) wrote: > > On Tue, Feb 09, 2021 at 07:02:16PM +0000, Dr. David Alan Gilbert (git) wrote: > > > + 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) { > > > > The flag name is specific to map requests but it's shared with the IO > > request. Perhaps rename the flags? > > They're both read/write's; do you have a preferred alternative? VHOST_USER_FS_FLAG_<what it does> (read? readwrite? etc) Stefan
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;