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]);
+ 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;
--
2.31.1
