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Re: [Virtio-fs] [PATCH v2 08/25] DAX: virtio-fs: Add vhost-user slave co
From: |
Greg Kurz |
Subject: |
Re: [Virtio-fs] [PATCH v2 08/25] DAX: virtio-fs: Add vhost-user slave commands for mapping |
Date: |
Wed, 14 Apr 2021 18:35:07 +0200 |
On Wed, 14 Apr 2021 16:51:20 +0100
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@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 <dgilbert@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".
> + 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;
>
- [PATCH v2 00/25] virtiofs dax patches, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 01/25] DAX: vhost-user: Rework slave return values, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 03/25] DAX: libvhost-user: Route slave message payload, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 04/25] DAX: libvhost-user: Allow popping a queue element with bad pointers, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 02/25] virtiofsd: Don't assume header layout, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 05/25] DAX subprojects/libvhost-user: Add virtio-fs slave types, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 10/25] DAX: virtiofsd Add cache accessor functions, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 08/25] DAX: virtio-fs: Add vhost-user slave commands for mapping, Dr. David Alan Gilbert (git), 2021/04/14
- Re: [Virtio-fs] [PATCH v2 08/25] DAX: virtio-fs: Add vhost-user slave commands for mapping,
Greg Kurz <=
- [PATCH v2 07/25] DAX: virtio-fs: Add cache BAR, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 09/25] DAX: virtio-fs: Fill in slave commands for mapping, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 12/25] DAX: virtiofsd: Add setup/remove mapping handlers to passthrough_ll, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 06/25] DAX: virtio: Add shared memory capability, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 13/25] DAX: virtiofsd: Wire up passthrough_ll's lo_setupmapping, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 14/25] DAX: virtiofsd: Make lo_removemapping() work, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 16/25] DAX: virtiofsd: Perform an unmap on destroy, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 15/25] DAX: virtiofsd: route se down to destroy method, Dr. David Alan Gilbert (git), 2021/04/14
- [PATCH v2 17/25] DAX/unmap: virtiofsd: Add VHOST_USER_SLAVE_FS_IO, Dr. David Alan Gilbert (git), 2021/04/14