[PATCH v8 0/3] libxl: save/restore qemu physmap

[PATCH v8 0/3] libxl: save/restore qemu physmap

[Stefano Stabellini]

Hi all,
this patch series introduces a new xc_save_id called
XC_SAVE_ID_TOOLSTACK to save/restore toolstack specific information.
Libxl is going to use the new save_id to save and restore qemu's
physmap.

The QEMU side of this patch series has been accepted, so it is now safe
to commit it to xen-unstable.


Changes in v8:
- return an error on restore if toolstack data is available but no
toolstack callback has been provided.


Changes in v7:
- log error messages on error paths;

- make the toolstack save/restore functions more readable.


Changes in v6:

- rebased on "kexec: Fix printing of paddr_t in 32bit mode.";

- use the command "xen-save-devices-state" to save the QEMU devices
state.



Changes in v5:

- rebased on "arm: lr register in hyp mode is really LR_usr.".



Changes in v4:

- addressed Shriram's comments about the first patch: saving/restoring
toolstack extra information should work we Remus too now;

- added a new patch to use QMP "save_devices" command rather than
"migrate" to save QEMU's device state.



Changes in v3:

- rebased the series;

- xc_domain_restore: read the toolstack data in pagebuf_get_one, call
the callback at finish_hvm;



Changes in v2:

- xc_domain_save frees the buffer allocated by the callback;

- introduce a version number in the libxl save record;

- define libxl__physmap_info and use it to read/store information to the
buffer.


Stefano Stabellini (3):
      libxc: introduce XC_SAVE_ID_TOOLSTACK
      libxl: save/restore qemu's physmap
      libxl_qmp: remove libxl__qmp_migrate, introduce libxl__qmp_save

 tools/libxc/xc_domain_restore.c |   53 ++++++++++++-
 tools/libxc/xc_domain_save.c    |   17 ++++
 tools/libxc/xenguest.h          |   23 +++++-
 tools/libxc/xg_save_restore.h   |    1 +
 tools/libxl/libxl_dom.c         |  174 ++++++++++++++++++++++++++++++++++++---
 tools/libxl/libxl_internal.h    |    2 +-
 tools/libxl/libxl_qmp.c         |   82 +------------------
 tools/xcutils/xc_restore.c      |    2 +-
 8 files changed, 260 insertions(+), 94 deletions(-)


Cheers,

Stefano

[PATCH v8 1/3] libxc: introduce XC_SAVE_ID_TOOLSTACK

[Stefano Stabellini]

Introduce a new save_id to save/restore toolstack specific extra
information.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxc/xc_domain_restore.c |   53 ++++++++++++++++++++++++++++++++++++++-
 tools/libxc/xc_domain_save.c    |   17 ++++++++++++
 tools/libxc/xenguest.h          |   23 ++++++++++++++++-
 tools/libxc/xg_save_restore.h   |    1 +
 tools/libxl/libxl_dom.c         |    2 +-
 tools/xcutils/xc_restore.c      |    2 +-
 6 files changed, 94 insertions(+), 4 deletions(-)

diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
index 3e4d518..6227d43 100644
--- a/tools/libxc/xc_domain_restore.c
+++ b/tools/libxc/xc_domain_restore.c
@@ -659,6 +659,11 @@ static void tailbuf_free(tailbuf_t *buf)
         tailbuf_free_pv(&buf->u.pv);
 }
 
+struct toolstack_data_t {
+    uint8_t *data;
+    uint32_t len;
+};
+
 typedef struct {
     void* pages;
     /* pages is of length nr_physpages, pfn_types is of length nr_pages */
@@ -685,6 +690,8 @@ typedef struct {
     uint64_t acpi_ioport_location;
     uint64_t viridian;
     uint64_t vm_generationid_addr;
+
+    struct toolstack_data_t tdata;
 } pagebuf_t;
 
 static int pagebuf_init(pagebuf_t* buf)
@@ -695,6 +702,10 @@ static int pagebuf_init(pagebuf_t* buf)
 
 static void pagebuf_free(pagebuf_t* buf)
 {
+    if (buf->tdata.data != NULL) {
+        free(buf->tdata.data);
+        buf->tdata.data = NULL;
+    }
     if (buf->pages) {
         free(buf->pages);
         buf->pages = NULL;
@@ -863,6 +874,19 @@ static int pagebuf_get_one(xc_interface *xch, struct restore_ctx *ctx,
         }
         return pagebuf_get_one(xch, ctx, buf, fd, dom);
 
+    case XC_SAVE_ID_TOOLSTACK:
+        {
+            RDEXACT(fd, &buf->tdata.len, sizeof(buf->tdata.len));
+            buf->tdata.data = (uint8_t*) realloc(buf->tdata.data, buf->tdata.len);
+            if ( buf->tdata.data == NULL )
+            {
+                PERROR("error memory allocation");
+                return -1;
+            }
+            RDEXACT(fd, buf->tdata.data, buf->tdata.len);
+            return pagebuf_get_one(xch, ctx, buf, fd, dom);
+        }
+
     case XC_SAVE_ID_ENABLE_COMPRESSION:
         /* We cannot set compression flag directly in pagebuf structure,
          * since this pagebuf still has uncompressed pages that are yet to
@@ -1299,7 +1323,8 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       int no_incr_generationid,
-                      unsigned long *vm_generationid_addr)
+                      unsigned long *vm_generationid_addr,
+                      struct restore_callbacks *callbacks)
 {
     DECLARE_DOMCTL;
     int rc = 1, frc, i, j, n, m, pae_extended_cr3 = 0, ext_vcpucontext = 0;
@@ -1347,6 +1372,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
 
     pagebuf_t pagebuf;
     tailbuf_t tailbuf, tmptail;
+    struct toolstack_data_t tdata, tdatatmp;
     void* vcpup;
     uint64_t console_pfn = 0;
 
@@ -1359,6 +1385,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
     pagebuf_init(&pagebuf);
     memset(&tailbuf, 0, sizeof(tailbuf));
     tailbuf.ishvm = hvm;
+    memset(&tdata, 0, sizeof(tdata));
 
     memset(ctx, 0, sizeof(*ctx));
 
@@ -1624,6 +1651,10 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
         ERROR("Error, unknow acpi ioport location (%i)", pagebuf.acpi_ioport_location);
     }
 
+    tdatatmp = tdata;
+    tdata = pagebuf.tdata;
+    pagebuf.tdata = tdatatmp;
+
     if ( ctx->last_checkpoint )
     {
         // DPRINTF("Last checkpoint, finishing\n");
@@ -2074,6 +2105,26 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
     goto out;
 
   finish_hvm:
+    if ( tdata.data != NULL )
+    {
+        if ( callbacks != NULL && callbacks->toolstack_restore != NULL )
+        {
+            rc = callbacks->toolstack_restore(dom, tdata.data, tdata.len,
+                        callbacks->data);
+            free(tdata.data);
+            if ( rc < 0 )
+            {
+                PERROR("error calling toolstack_restore");
+                goto out;
+            }
+        } else {
+            rc = -1;
+            ERROR("toolstack data available but no callback provided\n");
+            free(tdata.data);
+            goto out;
+        }
+    }
+
     /* Dump the QEMU state to a state file for QEMU to load */
     if ( dump_qemu(xch, dom, &tailbuf.u.hvm) ) {
         PERROR("Error dumping QEMU state to file");
diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
index a9216dd..fcc7718 100644
--- a/tools/libxc/xc_domain_save.c
+++ b/tools/libxc/xc_domain_save.c
@@ -1723,6 +1723,23 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
         }
     }
 
+    if ( callbacks != NULL && callbacks->toolstack_save != NULL )
+    {
+        int id = XC_SAVE_ID_TOOLSTACK;
+        uint8_t *buf;
+        uint32_t len;
+
+        if ( callbacks->toolstack_save(dom, &buf, &len, callbacks->data) < 0 )
+        {
+            PERROR("Error calling toolstack_save");
+            goto out;
+        }
+        wrexact(io_fd, &id, sizeof(id));
+        wrexact(io_fd, &len, sizeof(len));
+        wrexact(io_fd, buf, len);
+        free(buf);
+    }
+
     if ( !callbacks->checkpoint )
     {
         /*
diff --git a/tools/libxc/xenguest.h b/tools/libxc/xenguest.h
index 8d885d3..6435f65 100644
--- a/tools/libxc/xenguest.h
+++ b/tools/libxc/xenguest.h
@@ -44,6 +44,14 @@ struct save_callbacks {
     /* Enable qemu-dm logging dirty pages to xen */
     int (*switch_qemu_logdirty)(int domid, unsigned enable, void *data); /* HVM only */
 
+    /* Save toolstack specific data
+     * @param buf the buffer with the data to be saved
+     * @param len the length of the buffer
+     * The callee allocates the buffer, the caller frees it (buffer must
+     * be free'able).
+     */
+    int (*toolstack_save)(uint32_t domid, uint8_t **buf, uint32_t *len, void *data);
+
     /* to be provided as the last argument to each callback function */
     void* data;
 };
@@ -62,6 +70,16 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
                    unsigned long vm_generationid_addr);
 
 
+/* callbacks provided by xc_domain_restore */
+struct restore_callbacks {
+    /* callback to restore toolstack specific data */
+    int (*toolstack_restore)(uint32_t domid, uint8_t *buf,
+            uint32_t size, void* data);
+
+    /* to be provided as the last argument to each callback function */
+    void* data;
+};
+
 /**
  * This function will restore a saved domain.
  *
@@ -75,6 +93,8 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
  * @parm superpages non-zero to allocate guest memory with superpages
  * @parm no_incr_generationid non-zero if generation id is NOT to be incremented
  * @parm vm_generationid_addr returned with the address of the generation id buffer
+ * @parm callbacks non-NULL to receive a callback to restore toolstack
+ *       specific data
  * @return 0 on success, -1 on failure
  */
 int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
@@ -83,7 +103,8 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       int no_incr_generationid,
-		      unsigned long *vm_generationid_addr);
+                      unsigned long *vm_generationid_addr,
+                      struct restore_callbacks *callbacks);
 /**
  * xc_domain_restore writes a file to disk that contains the device
  * model saved state.
diff --git a/tools/libxc/xg_save_restore.h b/tools/libxc/xg_save_restore.h
index 89f3504..04e7892 100644
--- a/tools/libxc/xg_save_restore.h
+++ b/tools/libxc/xg_save_restore.h
@@ -258,6 +258,7 @@
 #define XC_SAVE_ID_HVM_PAGING_RING_PFN  -15
 #define XC_SAVE_ID_HVM_ACCESS_RING_PFN  -16
 #define XC_SAVE_ID_HVM_SHARING_RING_PFN -17
+#define XC_SAVE_ID_TOOLSTACK          -18 /* Optional toolstack specific info */
 
 /*
 ** We process save/restore/migrate in batches of pages; the below
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 0bdd654..7f140b4 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -425,7 +425,7 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
                            state->store_domid, state->console_port,
                            &state->console_mfn, state->console_domid,
                            hvm, pae, superpages, no_incr_generationid,
-                           &state->vm_generationid_addr);
+                           &state->vm_generationid_addr, NULL);
     if ( rc ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "restoring domain");
         return ERROR_FAIL;
diff --git a/tools/xcutils/xc_restore.c b/tools/xcutils/xc_restore.c
index e41a133..0235579 100644
--- a/tools/xcutils/xc_restore.c
+++ b/tools/xcutils/xc_restore.c
@@ -47,7 +47,7 @@ main(int argc, char **argv)
 
     ret = xc_domain_restore(xch, io_fd, domid, store_evtchn, &store_mfn, 0,
                             console_evtchn, &console_mfn, 0, hvm, pae, superpages,
-                            0, NULL);
+                            0, NULL, NULL);
 
     if ( ret == 0 )
     {
-- 
1.7.2.5

[PATCH v8 2/3] libxl: save/restore qemu's physmap

[Stefano Stabellini]

Read Qemu's physmap from xenstore and save it using toolstack_save.
Restore Qemu's physmap using toolstack_restore.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxl/libxl_dom.c |  163 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 162 insertions(+), 1 deletions(-)

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 7f140b4..1eb328b 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -394,6 +394,79 @@ int libxl__qemu_traditional_cmd(libxl__gc *gc, uint32_t domid,
     return libxl__xs_write(gc, XBT_NULL, path, "%s", cmd);
 }
 
+struct libxl__physmap_info {
+    uint64_t phys_offset;
+    uint64_t start_addr;
+    uint64_t size;
+    uint32_t namelen;
+    char name[];
+};
+
+#define TOOLSTACK_SAVE_VERSION 1
+
+static inline char *restore_helper(libxl__gc *gc, uint32_t domid,
+        uint64_t phys_offset, char *node)
+{
+    return libxl__sprintf(gc,
+            "/local/domain/0/device-model/%d/physmap/%"PRIx64"/%s",
+            domid, phys_offset, node);
+}
+
+static int libxl__toolstack_restore(uint32_t domid, uint8_t *buf,
+        uint32_t size, void *data)
+{
+    libxl__gc *gc = (libxl__gc *) data;
+    libxl_ctx *ctx = gc->owner;
+    int i, ret;
+    uint8_t *ptr = buf;
+    uint32_t count = 0, version = 0;
+    struct libxl__physmap_info* pi;
+    char *xs_path;
+
+    if (size < sizeof(version) + sizeof(count)) {
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "wrong size");
+        return -1;
+    }
+
+    memcpy(&version, ptr, sizeof(version));
+    ptr += sizeof(version);
+
+    if (version != TOOLSTACK_SAVE_VERSION) {
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "wrong version");
+        return -1;
+    }
+
+    memcpy(&count, ptr, sizeof(count));
+    ptr += sizeof(count);
+ 
+    if (size < sizeof(version) + sizeof(count) +
+            count * (sizeof(struct libxl__physmap_info))) {
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "wrong size");
+        return -1;
+    }
+
+    for (i = 0; i < count; i++) {
+        pi = (struct libxl__physmap_info*) ptr;
+        ptr += sizeof(struct libxl__physmap_info) + pi->namelen;
+
+        xs_path = restore_helper(gc, domid, pi->phys_offset, "start_addr");
+        ret = libxl__xs_write(gc, 0, xs_path, "%"PRIx64, pi->start_addr);
+        if (ret)
+            return -1;
+        xs_path = restore_helper(gc, domid, pi->phys_offset, "size");
+        ret = libxl__xs_write(gc, 0, xs_path, "%"PRIx64, pi->size);
+        if (ret)
+            return -1;
+        if (pi->namelen > 0) {
+            xs_path = restore_helper(gc, domid, pi->phys_offset, "name");
+            ret = libxl__xs_write(gc, 0, xs_path, "%s", pi->name);
+            if (ret)
+                return -1;
+        }
+    }
+    return 0;
+}
+
 int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
                                  libxl_domain_build_info *info,
                                  libxl__domain_build_state *state,
@@ -403,6 +476,7 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
     /* read signature */
     int rc;
     int hvm, pae, superpages;
+    struct restore_callbacks callbacks;
     int no_incr_generationid;
     switch (info->type) {
     case LIBXL_DOMAIN_TYPE_HVM:
@@ -410,6 +484,8 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
         superpages = 1;
         pae = libxl_defbool_val(info->u.hvm.pae);
         no_incr_generationid = !libxl_defbool_val(info->u.hvm.incr_generationid);
+        callbacks.toolstack_restore = libxl__toolstack_restore;
+        callbacks.data = gc;
         break;
     case LIBXL_DOMAIN_TYPE_PV:
         hvm = 0;
@@ -425,7 +501,7 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
                            state->store_domid, state->console_port,
                            &state->console_mfn, state->console_domid,
                            hvm, pae, superpages, no_incr_generationid,
-                           &state->vm_generationid_addr, NULL);
+                           &state->vm_generationid_addr, &callbacks);
     if ( rc ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "restoring domain");
         return ERROR_FAIL;
@@ -580,6 +656,90 @@ static int libxl__domain_suspend_common_callback(void *data)
     return 0;
 }
 
+static inline char *save_helper(libxl__gc *gc, uint32_t domid,
+        char *phys_offset, char *node)
+{
+    return libxl__sprintf(gc,
+            "/local/domain/0/device-model/%d/physmap/%s/%s",
+            domid, phys_offset, node);
+}
+
+static int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
+        uint32_t *len, void *data)
+{
+    struct suspendinfo *si = (struct suspendinfo *) data;
+    libxl__gc *gc = (libxl__gc *) si->gc;
+    libxl_ctx *ctx = gc->owner;
+    int i = 0;
+    char *start_addr = NULL, *size = NULL, *phys_offset = NULL, *name = NULL;
+    unsigned int num = 0;
+    uint32_t count = 0, version = TOOLSTACK_SAVE_VERSION, namelen = 0;
+    uint8_t *ptr = NULL;
+    char **entries = NULL;
+    struct libxl__physmap_info *pi;
+
+    entries = libxl__xs_directory(gc, 0, libxl__sprintf(gc,
+                "/local/domain/0/device-model/%d/physmap", domid), &num);
+    count = num;
+
+    *len = sizeof(version) + sizeof(count);
+    *buf = calloc(1, *len);
+    ptr = *buf;
+    if (*buf == NULL)
+        return -1;
+
+    memcpy(ptr, &version, sizeof(version));
+    ptr += sizeof(version);
+    memcpy(ptr, &count, sizeof(count));
+    ptr += sizeof(count);
+
+    for (i = 0; i < count; i++) {
+        unsigned long offset;
+        char *xs_path;
+        phys_offset = entries[i];
+        if (phys_offset == NULL) {
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "phys_offset %d is NULL", i);
+            return -1;
+        }
+
+        xs_path = save_helper(gc, domid, phys_offset, "start_addr");
+        start_addr = libxl__xs_read(gc, 0, xs_path);
+        if (start_addr == NULL) {
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "%s is NULL", xs_path);
+            return -1;
+        }
+
+        xs_path = save_helper(gc, domid, phys_offset, "size");
+        size = libxl__xs_read(gc, 0, xs_path);
+        if (size == NULL) {
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "%s is NULL", xs_path);
+            return -1;
+        }
+
+        xs_path = save_helper(gc, domid, phys_offset, "name");
+        name = libxl__xs_read(gc, 0, xs_path);
+        if (name == NULL)
+            namelen = 0;
+        else
+            namelen = strlen(name) + 1;
+        *len += namelen + sizeof(struct libxl__physmap_info);
+        offset = ptr - (*buf);
+        *buf = realloc(*buf, *len);
+        if (*buf == NULL)
+            return -1;
+        ptr = (*buf) + offset;
+        pi = (struct libxl__physmap_info *) ptr;
+        pi->phys_offset = strtoll(phys_offset, NULL, 16);
+        pi->start_addr = strtoll(start_addr, NULL, 16);
+        pi->size = strtoll(size, NULL, 16);
+        pi->namelen = namelen;
+        memcpy(pi->name, name, namelen);
+        ptr += sizeof(struct libxl__physmap_info) + namelen;
+    }
+
+    return 0;
+}
+
 int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
                                  libxl_domain_type type,
                                  int live, int debug)
@@ -642,6 +802,7 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
     memset(&callbacks, 0, sizeof(callbacks));
     callbacks.suspend = libxl__domain_suspend_common_callback;
     callbacks.switch_qemu_logdirty = libxl__domain_suspend_common_switch_qemu_logdirty;
+    callbacks.toolstack_save = libxl__toolstack_save;
     callbacks.data = &si;
 
     rc = xc_domain_save(ctx->xch, fd, domid, 0, 0, flags, &callbacks,
-- 
1.7.2.5

[PATCH v8 3/3] libxl_qmp: remove libxl__qmp_migrate, introduce libxl__qmp_save

[Stefano Stabellini]

Following the recent changes to upstream Qemu, the best monitor command
to suit or needs is "xen-save-devices-state" rather than "migrate".
This patch removes libxl__qmp_migrate and introduces libxl__qmp_save
instead, that uses "xen-save-devices-state".

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxl/libxl_dom.c      |   11 +-----
 tools/libxl/libxl_internal.h |    2 +-
 tools/libxl/libxl_qmp.c      |   82 ++----------------------------------------
 3 files changed, 5 insertions(+), 90 deletions(-)

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 1eb328b..b209262 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -845,18 +845,9 @@ int libxl__domain_save_device_model(libxl__gc *gc, uint32_t domid, int fd)
         break;
     }
     case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
-        fd2 = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
-        if (fd2 < 0) {
-            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
-                             "Unable to create a QEMU save file\n");
-            return ERROR_FAIL;
-        }
-        /* Save DM state into fd2 */
-        ret = libxl__qmp_migrate(gc, domid, fd2);
+        ret = libxl__qmp_save(gc, domid, (char *)filename);
         if (ret)
             goto out;
-        close(fd2);
-        fd2 = -1;
         break;
     default:
         return ERROR_INVAL;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index e0a1070..b5cce17 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1028,7 +1028,7 @@ _hidden int libxl__qmp_pci_add(libxl__gc *gc, int d, libxl_device_pci *pcidev);
 _hidden int libxl__qmp_pci_del(libxl__gc *gc, int domid,
                                libxl_device_pci *pcidev);
 /* Save current QEMU state into fd. */
-_hidden int libxl__qmp_migrate(libxl__gc *gc, int domid, int fd);
+_hidden int libxl__qmp_save(libxl__gc *gc, int domid, const char *filename);
 /* close and free the QMP handler */
 _hidden void libxl__qmp_close(libxl__qmp_handler *qmp);
 /* remove the socket file, if the file has already been removed,
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index f5a3edc..9a6ecb6 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -538,52 +538,6 @@ out:
     return rc;
 }
 
-static int qmp_send_fd(libxl__gc *gc, libxl__qmp_handler *qmp,
-                       libxl_key_value_list *args,
-                       qmp_callback_t callback, void *opaque,
-                       qmp_request_context *context,
-                       int fd)
-{
-    struct msghdr msg = { 0 };
-    struct cmsghdr *cmsg;
-    char control[CMSG_SPACE(sizeof (fd))];
-    struct iovec iov;
-    char *buf = NULL;
-
-    buf = qmp_send_prepare(gc, qmp, "getfd", args, callback, opaque, context);
-
-    /* Response data */
-    iov.iov_base = buf;
-    iov.iov_len  = strlen(buf);
-
-    /* compose the message */
-    msg.msg_iov = &iov;
-    msg.msg_iovlen = 1;
-    msg.msg_control = control;
-    msg.msg_controllen = sizeof (control);
-
-    /* attach open fd */
-    cmsg = CMSG_FIRSTHDR(&msg);
-    cmsg->cmsg_level = SOL_SOCKET;
-    cmsg->cmsg_type = SCM_RIGHTS;
-    cmsg->cmsg_len = CMSG_LEN(sizeof (fd));
-    *(int *)CMSG_DATA(cmsg) = fd;
-
-    msg.msg_controllen = cmsg->cmsg_len;
-
-    if (sendmsg(qmp->qmp_fd, &msg, 0) < 0) {
-        LIBXL__LOG_ERRNO(qmp->ctx, LIBXL__LOG_ERROR,
-                         "Failed to send a QMP message to QEMU.");
-        return ERROR_FAIL;
-    }
-    if (libxl_write_exactly(qmp->ctx, qmp->qmp_fd, "\r\n", 2,
-                            "CRLF", "QMP socket")) {
-        return ERROR_FAIL;
-    }
-
-    return qmp->last_id_used;
-}
-
 static int qmp_synchronous_send(libxl__qmp_handler *qmp, const char *cmd,
                                 libxl_key_value_list *args,
                                 qmp_callback_t callback, void *opaque,
@@ -817,34 +771,8 @@ int libxl__qmp_pci_del(libxl__gc *gc, int domid, libxl_device_pci *pcidev)
     return qmp_device_del(gc, domid, id);
 }
 
-static int qmp_getfd(libxl__gc *gc, libxl__qmp_handler *qmp,
-                     int fd, const char *name)
-{
-    flexarray_t *parameters = NULL;
-    libxl_key_value_list args = NULL;
-    int rc = 0;
-
-    parameters = flexarray_make(2, 1);
-    if (!parameters)
-        return ERROR_NOMEM;
-    flexarray_append_pair(parameters, "fdname", (char*)name);
-    args = libxl__xs_kvs_of_flexarray(gc, parameters, parameters->count);
-    if (!args) {
-        rc = ERROR_NOMEM;
-        goto out;
-    }
-
-    if (qmp_send_fd(gc, qmp, &args, NULL, NULL, NULL, fd) < 0) {
-        rc = ERROR_FAIL;
-    }
-out:
-    flexarray_free(parameters);
-    return rc;
-}
-
-int libxl__qmp_migrate(libxl__gc *gc, int domid, int fd)
+int libxl__qmp_save(libxl__gc *gc, int domid, const char *filename)
 {
-#define MIGRATE_FD_NAME "dm-migrate"
     libxl__qmp_handler *qmp = NULL;
     flexarray_t *parameters = NULL;
     libxl_key_value_list args = NULL;
@@ -854,23 +782,19 @@ int libxl__qmp_migrate(libxl__gc *gc, int domid, int fd)
     if (!qmp)
         return ERROR_FAIL;
 
-    rc = qmp_getfd(gc, qmp, fd, MIGRATE_FD_NAME);
-    if (rc)
-        goto out;
-
     parameters = flexarray_make(2, 1);
     if (!parameters) {
         rc = ERROR_NOMEM;
         goto out;
     }
-    flexarray_append_pair(parameters, "uri", "fd:" MIGRATE_FD_NAME);
+    flexarray_append_pair(parameters, "filename", (char *)filename);
     args = libxl__xs_kvs_of_flexarray(gc, parameters, parameters->count);
     if (!args) {
         rc = ERROR_NOMEM;
         goto out2;
     }
 
-    rc = qmp_synchronous_send(qmp, "migrate", &args,
+    rc = qmp_synchronous_send(qmp, "xen-save-devices-state", &args,
                               NULL, NULL, qmp->timeout);
 
 out2:
-- 
1.7.2.5

Re: [PATCH v8 0/3] libxl: save/restore qemu physmap

[Shriram Rajagopalan]

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I ll wait until this series gets in before respinning my patch series (if
need be). :)


shriram

On Fri, Apr 13, 2012 at 4:40 AM, Stefano Stabellini <
Stefano.Stabellini@eu.citrix.com> wrote:

> Hi all,
> this patch series introduces a new xc_save_id called
> XC_SAVE_ID_TOOLSTACK to save/restore toolstack specific information.
> Libxl is going to use the new save_id to save and restore qemu's
> physmap.
>
> The QEMU side of this patch series has been accepted, so it is now safe
> to commit it to xen-unstable.
>
>
> Changes in v8:
> - return an error on restore if toolstack data is available but no
> toolstack callback has been provided.
>
>
> Changes in v7:
> - log error messages on error paths;
>
> - make the toolstack save/restore functions more readable.
>
>
> Changes in v6:
>
> - rebased on "kexec: Fix printing of paddr_t in 32bit mode.";
>
> - use the command "xen-save-devices-state" to save the QEMU devices
> state.
>
>
>
> Changes in v5:
>
> - rebased on "arm: lr register in hyp mode is really LR_usr.".
>
>
>
> Changes in v4:
>
> - addressed Shriram's comments about the first patch: saving/restoring
> toolstack extra information should work we Remus too now;
>
> - added a new patch to use QMP "save_devices" command rather than
> "migrate" to save QEMU's device state.
>
>
>
> Changes in v3:
>
> - rebased the series;
>
> - xc_domain_restore: read the toolstack data in pagebuf_get_one, call
> the callback at finish_hvm;
>
>
>
> Changes in v2:
>
> - xc_domain_save frees the buffer allocated by the callback;
>
> - introduce a version number in the libxl save record;
>
> - define libxl__physmap_info and use it to read/store information to the
> buffer.
>
>
> Stefano Stabellini (3):
>      libxc: introduce XC_SAVE_ID_TOOLSTACK
>      libxl: save/restore qemu's physmap
>      libxl_qmp: remove libxl__qmp_migrate, introduce libxl__qmp_save
>
>  tools/libxc/xc_domain_restore.c |   53 ++++++++++++-
>  tools/libxc/xc_domain_save.c    |   17 ++++
>  tools/libxc/xenguest.h          |   23 +++++-
>  tools/libxc/xg_save_restore.h   |    1 +
>  tools/libxl/libxl_dom.c         |  174
> ++++++++++++++++++++++++++++++++++++---
>  tools/libxl/libxl_internal.h    |    2 +-
>  tools/libxl/libxl_qmp.c         |   82 +------------------
>  tools/xcutils/xc_restore.c      |    2 +-
>  8 files changed, 260 insertions(+), 94 deletions(-)
>
>
> Cheers,
>
> Stefano
>
>

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Re: [PATCH v8 3/3] libxl_qmp: remove libxl__qmp_migrate, introduce libxl__qmp_save

[Ian Jackson]

Stefano Stabellini writes ("[PATCH v8 3/3] libxl_qmp: remove libxl__qmp_migrate, introduce libxl__qmp_save"):
> Following the recent changes to upstream Qemu, the best monitor command
> to suit or needs is "xen-save-devices-state" rather than "migrate".
> This patch removes libxl__qmp_migrate and introduces libxl__qmp_save
> instead, that uses "xen-save-devices-state".
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

You've dropped my ack on this patch.

Ian.

Re: [PATCH v8 0/3] libxl: save/restore qemu physmap

[Ian Jackson]

Stefano Stabellini writes ("[Xen-devel] [PATCH v8 0/3] libxl: save/restore qemu physmap"):
> this patch series introduces a new xc_save_id called
> XC_SAVE_ID_TOOLSTACK to save/restore toolstack specific information.
> Libxl is going to use the new save_id to save and restore qemu's
> physmap.

All 3:

Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

Thanks,
Ian.