* Greg Kurz (gr...@kaod.org) wrote:
> On Wed, 14 Apr 2021 16:51:20 +0100
> "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote:
>
> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
> >
> > The daemon may request that fd's be mapped into the virtio-fs cache
> > visible to the guest.
> > These mappings are triggered by commands sent over the slave fd
> > from the daemon.
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > docs/interop/vhost-user.rst | 21 ++++++++
> > hw/virtio/vhost-user-fs.c | 66 +++++++++++++++++++++++
> > hw/virtio/vhost-user.c | 25 +++++++++
> > include/hw/virtio/vhost-user-fs.h | 33 ++++++++++++
> > subprojects/libvhost-user/libvhost-user.h | 2 +
> > 5 files changed, 147 insertions(+)
> >
> > diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
> > index d6085f7045..09aee3565d 100644
> > --- a/docs/interop/vhost-user.rst
> > +++ b/docs/interop/vhost-user.rst
> > @@ -1432,6 +1432,27 @@ Slave message types
> >
> > The state.num field is currently reserved and must be set to 0.
> >
> > +``VHOST_USER_SLAVE_FS_MAP``
> > + :id: 6
> > + :equivalent ioctl: N/A
> > + :slave payload: ``struct VhostUserFSSlaveMsg``
> > + :master payload: N/A
> > +
> > + Requests that an fd, provided in the ancillary data, be mmapped
> > + into the virtio-fs cache; multiple chunks can be mapped in one
> > + command.
> > + A reply is generated indicating whether mapping succeeded.
> > +
> > +``VHOST_USER_SLAVE_FS_UNMAP``
> > + :id: 7
> > + :equivalent ioctl: N/A
> > + :slave payload: ``struct VhostUserFSSlaveMsg``
> > + :master payload: N/A
> > +
> > + Requests that the range in the virtio-fs cache is unmapped;
> > + multiple chunks can be unmapped in one command.
> > + A reply is generated indicating whether unmapping succeeded.
> > +
> > .. _reply_ack:
> >
> > VHOST_USER_PROTOCOL_F_REPLY_ACK
> > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> > index dd0a02aa99..169a146e72 100644
> > --- a/hw/virtio/vhost-user-fs.c
> > +++ b/hw/virtio/vhost-user-fs.c
> > @@ -45,6 +45,72 @@ static const int user_feature_bits[] = {
> > #define DAX_WINDOW_PROT PROT_NONE
> > #endif
> >
> > +/*
> > + * The message apparently had 'received_size' bytes, check this
> > + * matches the count in the message.
> > + *
> > + * Returns true if the size matches.
> > + */
> > +static bool check_slave_message_entries(const VhostUserFSSlaveMsg *sm,
> > + int received_size)
> > +{
> > + int tmp;
> > +
> > + /*
> > + * VhostUserFSSlaveMsg consists of a body followed by 'n' entries,
> > + * (each VhostUserFSSlaveMsgEntry). There's a maximum of
> > + * VHOST_USER_FS_SLAVE_MAX_ENTRIES of these.
> > + */
> > + if (received_size <= sizeof(VhostUserFSSlaveMsg)) {
> > + error_report("%s: Short VhostUserFSSlaveMsg size, %d", __func__,
> > + received_size);
> > + return false;
> > + }
> > +
> > + tmp = received_size - sizeof(VhostUserFSSlaveMsg);
> > + if (tmp % sizeof(VhostUserFSSlaveMsgEntry)) {
> > + error_report("%s: Non-multiple VhostUserFSSlaveMsg size, %d",
> > __func__,
> > + received_size);
> > + return false;
> > + }
> > +
> > + tmp /= sizeof(VhostUserFSSlaveMsgEntry);
> > + if (tmp != sm->count) {
> > + error_report("%s: VhostUserFSSlaveMsg count mismatch, %d count:
> > %d",
> > + __func__, tmp, sm->count);
> > + return false;
> > + }
> > +
> > + if (sm->count > VHOST_USER_FS_SLAVE_MAX_ENTRIES) {
> > + error_report("%s: VhostUserFSSlaveMsg too many entries: %d",
> > + __func__, sm->count);
> > + return false;
> > + }
> > + return true;
> > +}
> > +
> > +uint64_t vhost_user_fs_slave_map(struct vhost_dev *dev, int message_size,
> > + VhostUserFSSlaveMsg *sm, int fd)
> > +{
> > + if (!check_slave_message_entries(sm, message_size)) {
> > + return (uint64_t)-1;
> > + }
> > +
> > + /* TODO */
> > + return (uint64_t)-1;
> > +}
> > +
> > +uint64_t vhost_user_fs_slave_unmap(struct vhost_dev *dev, int message_size,
> > + VhostUserFSSlaveMsg *sm)
> > +{
> > + if (!check_slave_message_entries(sm, message_size)) {
> > + return (uint64_t)-1;
> > + }
> > +
> > + /* TODO */
> > + return (uint64_t)-1;
> > +}
> > +
> > 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 3e4a25e108..ad9170f8dc 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -12,6 +12,7 @@
> > #include "qapi/error.h"
> > #include "hw/virtio/vhost.h"
> > #include "hw/virtio/vhost-user.h"
> > +#include "hw/virtio/vhost-user-fs.h"
> > #include "hw/virtio/vhost-backend.h"
> > #include "hw/virtio/virtio.h"
> > #include "hw/virtio/virtio-net.h"
> > @@ -133,6 +134,10 @@ typedef enum VhostUserSlaveRequest {
> > VHOST_USER_SLAVE_IOTLB_MSG = 1,
> > VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2,
> > VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,
> > + VHOST_USER_SLAVE_VRING_CALL = 4,
> > + VHOST_USER_SLAVE_VRING_ERR = 5,
> > + VHOST_USER_SLAVE_FS_MAP = 6,
> > + VHOST_USER_SLAVE_FS_UNMAP = 7,
> > VHOST_USER_SLAVE_MAX
> > } VhostUserSlaveRequest;
> >
> > @@ -205,6 +210,16 @@ typedef struct {
> > uint32_t size; /* the following payload size */
> > } QEMU_PACKED VhostUserHeader;
> >
> > +/*
> > + * VhostUserFSSlaveMsg is special since it has a variable entry count,
> > + * but it does have a maximum, so make a type for that to fit in our union
> > + * for max size.
> > + */
> > +typedef struct {
> > + VhostUserFSSlaveMsg fs;
> > + VhostUserFSSlaveMsgEntry entries[VHOST_USER_FS_SLAVE_MAX_ENTRIES];
> > +} QEMU_PACKED VhostUserFSSlaveMsgMax;
> > +
> > typedef union {
> > #define VHOST_USER_VRING_IDX_MASK (0xff)
> > #define VHOST_USER_VRING_NOFD_MASK (0x1<<8)
> > @@ -219,6 +234,8 @@ typedef union {
> > VhostUserCryptoSession session;
> > VhostUserVringArea area;
> > VhostUserInflight inflight;
> > + VhostUserFSSlaveMsg fs;
> > + VhostUserFSSlaveMsg fs_max; /* Never actually used */
> > } VhostUserPayload;
> >
> > typedef struct VhostUserMsg {
> > @@ -1538,6 +1555,14 @@ static gboolean slave_read(QIOChannel *ioc,
> > GIOCondition condition,
> > ret = vhost_user_slave_handle_vring_host_notifier(dev,
> > &payload.area,
> > fd ? fd[0] : -1);
> > break;
> > +#ifdef CONFIG_VHOST_USER_FS
> > + case VHOST_USER_SLAVE_FS_MAP:
> > + ret = vhost_user_fs_slave_map(dev, hdr.size, &payload.fs, fd[0]);
>
> Since the QIOChannel conversion, the array of fds is dynamically allocated
> by qio_channel_readv_full_all() when needed. You should do "fd ? fd[0] : -1"
> like for vhost_user_slave_handle_vring_host_notifier() just above.
>
> Same goes for patch 17 "DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO".
Thanks; fixed!
Dave
> > + break;
> > + case VHOST_USER_SLAVE_FS_UNMAP:
> > + ret = vhost_user_fs_slave_unmap(dev, hdr.size, &payload.fs);
> > + break;
> > +#endif
> > default:
> > error_report("Received unexpected msg type: %d.", hdr.request);
> > ret = true;
> > diff --git a/include/hw/virtio/vhost-user-fs.h
> > b/include/hw/virtio/vhost-user-fs.h
> > index 04596799e3..0766f17548 100644
> > --- a/include/hw/virtio/vhost-user-fs.h
> > +++ b/include/hw/virtio/vhost-user-fs.h
> > @@ -23,6 +23,33 @@
> > #define TYPE_VHOST_USER_FS "vhost-user-fs-device"
> > OBJECT_DECLARE_SIMPLE_TYPE(VHostUserFS, VHOST_USER_FS)
> >
> > +/* Structures carried over the slave channel back to QEMU */
> > +#define VHOST_USER_FS_SLAVE_MAX_ENTRIES 32
> > +
> > +/* For the flags field of VhostUserFSSlaveMsg */
> > +#define VHOST_USER_FS_FLAG_MAP_R (1u << 0)
> > +#define VHOST_USER_FS_FLAG_MAP_W (1u << 1)
> > +
> > +typedef struct {
> > + /* Offsets within the file being mapped */
> > + uint64_t fd_offset;
> > + /* Offsets within the cache */
> > + uint64_t c_offset;
> > + /* Lengths of sections */
> > + uint64_t len;
> > + /* Flags, from VHOST_USER_FS_FLAG_* */
> > + uint64_t flags;
> > +} VhostUserFSSlaveMsgEntry;
> > +
> > +typedef struct {
> > + /* Number of entries */
> > + uint16_t count;
> > + /* Spare */
> > + uint16_t align;
> > +
> > + VhostUserFSSlaveMsgEntry entries[];
> > +} VhostUserFSSlaveMsg;
> > +
> > typedef struct {
> > CharBackend chardev;
> > char *tag;
> > @@ -46,4 +73,10 @@ struct VHostUserFS {
> > MemoryRegion cache;
> > };
> >
> > +/* Callbacks from the vhost-user code for slave commands */
> > +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);
> > +
> > #endif /* _QEMU_VHOST_USER_FS_H */
> > diff --git a/subprojects/libvhost-user/libvhost-user.h
> > b/subprojects/libvhost-user/libvhost-user.h
> > index 70fc61171f..a98c5f5c11 100644
> > --- a/subprojects/libvhost-user/libvhost-user.h
> > +++ b/subprojects/libvhost-user/libvhost-user.h
> > @@ -119,6 +119,8 @@ typedef enum VhostUserSlaveRequest {
> > VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,
> > VHOST_USER_SLAVE_VRING_CALL = 4,
> > VHOST_USER_SLAVE_VRING_ERR = 5,
> > + VHOST_USER_SLAVE_FS_MAP = 6,
> > + VHOST_USER_SLAVE_FS_UNMAP = 7,
> > VHOST_USER_SLAVE_MAX
> > } VhostUserSlaveRequest;
> >
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
