tools: VM generation ID save/restore and migrate.

Add code to track the address of the VM generation ID buffer across a
save/restore or migrate, and increment it as necessary.
The address of the buffer is written into xenstore by hvmloader at
boot time. It must be read from xenstore by the caller of
xc_domain_save() and then written back again by the caller of
xc_domain_restore().

Note that the changes to xc_save.c and xc_restore.c are merely
sufficient for them to build.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

diff --git a/tools/libxc/ia64/xc_ia64_linux_restore.c b/tools/libxc/ia64/xc_ia64_linux_restore.c
index 5a915aa9930406c30cb9b0d87097ae8910aa20cd..d199cbfac4a2516202905f5df4f87befebf87695 100644 (file)
--- a/tools/libxc/ia64/xc_ia64_linux_restore.c
+++ b/tools/libxc/ia64/xc_ia64_linux_restore.c
@@ -548,7 +548,9 @@ int
 xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                   unsigned int store_evtchn, unsigned long *store_mfn,
                   unsigned int console_evtchn, unsigned long *console_mfn,
-                  unsigned int hvm, unsigned int pae, int superpages)
+                  unsigned int hvm, unsigned int pae, int superpages,
+                  int no_incr_generationid,
+                  unsigned long *vm_generationid_addr)
 {
     DECLARE_DOMCTL;
     int rc = 1;

diff --git a/tools/libxc/ia64/xc_ia64_linux_save.c b/tools/libxc/ia64/xc_ia64_linux_save.c
index 52b37f1017f49493143e0c71052ddf450280dba8..5bb988cbd78ba3aa7b2b49da626963741084d52d 100644 (file)
--- a/tools/libxc/ia64/xc_ia64_linux_save.c
+++ b/tools/libxc/ia64/xc_ia64_linux_save.c
@@ -382,7 +382,8 @@ out:
 int
 xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
                uint32_t max_factor, uint32_t flags,
-               struct save_callbacks* callbacks, int hvm)
+               struct save_callbacks* callbacks, int hvm,
+               unsigned long vm_generationid_addr)
 {
     DECLARE_DOMCTL;
     xc_dominfo_t info;

diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
index 14451d1a591dd2340aa4b780b922774bd206fc93..3fda6f8c6856b79bb8125333a1da41bb90b348a4 100644 (file)
--- a/tools/libxc/xc_domain_restore.c
+++ b/tools/libxc/xc_domain_restore.c
@@ -681,6 +681,7 @@ typedef struct {
     uint64_t console_pfn;
     uint64_t acpi_ioport_location;
     uint64_t viridian;
+    uint64_t vm_generationid_addr;
 } pagebuf_t;
 
 static int pagebuf_init(pagebuf_t* buf)
@@ -860,6 +861,17 @@ static int pagebuf_get_one(xc_interface *xch, struct restore_ctx *ctx,
         }
         return compbuf_size;
 
+    case XC_SAVE_ID_HVM_GENERATION_ID_ADDR:
+        /* Skip padding 4 bytes then read the generation id buffer location. */
+        if ( RDEXACT(fd, &buf->vm_generationid_addr, sizeof(uint32_t)) ||
+             RDEXACT(fd, &buf->vm_generationid_addr, sizeof(uint64_t)) )
+        {
+            PERROR("error read the generation id buffer location");
+            return -1;
+        }
+        DPRINTF("read generation id buffer address");
+        return pagebuf_get_one(xch, ctx, buf, fd, dom);
+
     default:
         if ( (count > MAX_BATCH_SIZE) || (count < 0) ) {
             ERROR("Max batch size exceeded (%d). Giving up.", count);
@@ -1248,7 +1260,9 @@ static int apply_batch(xc_interface *xch, uint32_t dom, struct restore_ctx *ctx,
 int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned int store_evtchn, unsigned long *store_mfn,
                       unsigned int console_evtchn, unsigned long *console_mfn,
-                      unsigned int hvm, unsigned int pae, int superpages)
+                      unsigned int hvm, unsigned int pae, int superpages,
+                      int no_incr_generationid,
+                      unsigned long *vm_generationid_addr)
 {
     DECLARE_DOMCTL;
     int rc = 1, frc, i, j, n, m, pae_extended_cr3 = 0, ext_vcpucontext = 0;
@@ -1449,6 +1463,39 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                 xc_set_hvm_param(xch, dom, HVM_PARAM_VM86_TSS, pagebuf.vm86_tss);
             if ( pagebuf.console_pfn )
                 console_pfn = pagebuf.console_pfn;
+            if ( pagebuf.vm_generationid_addr ) {
+                if ( !no_incr_generationid ) {
+                    unsigned int offset;
+                    unsigned char *buf;
+                    unsigned long long generationid;
+
+                    /*
+                     * Map the VM generation id buffer and inject the new value.
+                     */
+
+                    pfn = pagebuf.vm_generationid_addr >> PAGE_SHIFT;
+                    offset = pagebuf.vm_generationid_addr & (PAGE_SIZE - 1);
+                
+                    if ( (pfn >= dinfo->p2m_size) ||
+                         (pfn_type[pfn] != XEN_DOMCTL_PFINFO_NOTAB) )
+                    {
+                        ERROR("generation id buffer frame is bad");
+                        goto out;
+                    }
+
+                    mfn = ctx->p2m[pfn];
+                    buf = xc_map_foreign_range(xch, dom, PAGE_SIZE,
+                                               PROT_READ | PROT_WRITE, mfn);
+
+                    generationid = *(unsigned long long *)(buf + offset);
+                    *(unsigned long long *)(buf + offset) = generationid + 1;
+
+                    munmap(buf, PAGE_SIZE);
+                }
+
+                *vm_generationid_addr = pagebuf.vm_generationid_addr;
+            }
+
             break;  /* our work here is done */
         }
 

diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c
index a6bb89475f62ced3bdc30515d592ed285712d93f..f473dd7c5ca4032032dee35fddca428466710fd5 100644 (file)
--- a/tools/libxc/xc_domain_save.c
+++ b/tools/libxc/xc_domain_save.c
@@ -804,7 +804,8 @@ static int save_tsc_info(xc_interface *xch, uint32_t dom, int io_fd)
 
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
                    uint32_t max_factor, uint32_t flags,
-                   struct save_callbacks* callbacks, int hvm)
+                   struct save_callbacks* callbacks, int hvm,
+                   unsigned long vm_generationid_addr)
 {
     xc_dominfo_t info;
     DECLARE_DOMCTL;
@@ -1616,6 +1617,16 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
             uint64_t data;
         } chunk = { 0, };
 
+        chunk.id = XC_SAVE_ID_HVM_GENERATION_ID_ADDR;
+        chunk.data = vm_generationid_addr;
+
+        if ( (chunk.data != 0) &&
+             wrexact(io_fd, &chunk, sizeof(chunk)) )
+        {
+            PERROR("Error when writing the generation id buffer location for guest");
+            goto out;
+        }
+
         chunk.id = XC_SAVE_ID_HVM_IDENT_PT;
         chunk.data = 0;
         xc_get_hvm_param(xch, dom, HVM_PARAM_IDENT_PT,

diff --git a/tools/libxc/xenguest.h b/tools/libxc/xenguest.h
index 4475ee92eedad42622187ad55eed815642d53dc2..60263709ce8544dcfec830d3ffc8c054106514bf 100644 (file)
--- a/tools/libxc/xenguest.h
+++ b/tools/libxc/xenguest.h
@@ -58,7 +58,8 @@ struct save_callbacks {
  */
 int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iters,
                    uint32_t max_factor, uint32_t flags /* XCFLAGS_xxx */,
-                   struct save_callbacks* callbacks, int hvm);
+                   struct save_callbacks* callbacks, int hvm,
+                   unsigned long vm_generationid_addr);
 
 
 /**
@@ -72,12 +73,16 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter
  * @parm hvm non-zero if this is a HVM restore
  * @parm pae non-zero if this HVM domain has PAE support enabled
  * @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
  * @return 0 on success, -1 on failure
  */
 int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom,
                       unsigned int store_evtchn, unsigned long *store_mfn,
                       unsigned int console_evtchn, unsigned long *console_mfn,
-                      unsigned int hvm, unsigned int pae, int superpages);
+                      unsigned int hvm, unsigned int pae, int superpages,
+                      int no_incr_generationid,
+                     unsigned long *vm_generationid_addr);
 /**
  * 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 c5e0743dcf9f6e644e3583a2b243631c1f40a013..6286b6814a9edc74c68183fb44febc5888a5c9dc 100644 (file)
--- a/tools/libxc/xg_save_restore.h
+++ b/tools/libxc/xg_save_restore.h
@@ -253,6 +253,7 @@
 #define XC_SAVE_ID_HVM_VIRIDIAN       -11
 #define XC_SAVE_ID_COMPRESSED_DATA    -12 /* Marker to indicate arrival of compressed data */
 #define XC_SAVE_ID_ENABLE_COMPRESSION -13 /* Marker to enable compression logic at receiver side */
+#define XC_SAVE_ID_HVM_GENERATION_ID_ADDR -14
 
 /*
 ** We process save/restore/migrate in batches of pages; the below

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index c0eaff5ef83e34525e66a268c346c20786f9a940..7b6a2f92d29e305b5fac6e9cd8ff66cc9efb35db 100644 (file)
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -99,6 +99,7 @@ int libxl_init_build_info(libxl_ctx *ctx,
         b_info->u.hvm.vpt_align = 1;
         b_info->u.hvm.timer_mode = 1;
         b_info->u.hvm.nested_hvm = 0;
+        b_info->u.hvm.no_incr_generationid = 0;
         break;
     case LIBXL_DOMAIN_TYPE_PV:
         b_info->u.pv.slack_memkb = 8 * 1024;

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index c898d897735faf8b3321760c514f53d79c29ca21..a4725fea32172d790894f14316dd872d9156ce72 100644 (file)
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -106,6 +106,7 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
 
     state->store_port = xc_evtchn_alloc_unbound(ctx->xch, domid, 0);
     state->console_port = xc_evtchn_alloc_unbound(ctx->xch, domid, 0);
+    state->vm_generationid_addr = 0;
     return 0;
 }
 
@@ -117,7 +118,7 @@ int libxl__build_post(libxl__gc *gc, uint32_t domid,
     libxl_ctx *ctx = libxl__gc_owner(gc);
     char *dom_path, *vm_path;
     xs_transaction_t t;
-    char **ents;
+    char **ents, **hvm_ents;
     int i;
 
     libxl_cpuid_apply_policy(ctx, domid);
@@ -143,6 +144,13 @@ int libxl__build_post(libxl__gc *gc, uint32_t domid,
                             ? "offline" : "online";
     }
 
+    hvm_ents = NULL;
+    if (info->type == LIBXL_DOMAIN_TYPE_HVM) {
+        hvm_ents = libxl__calloc(gc, 3, sizeof(char *));
+        hvm_ents[0] = "hvmloader/generation-id-address";
+        hvm_ents[1] = libxl__sprintf(gc, "0x%lx", state->vm_generationid_addr);
+    }
+
     dom_path = libxl__xs_get_dompath(gc, domid);
     if (!dom_path) {
         return ERROR_FAIL;
@@ -153,6 +161,9 @@ retry_transaction:
     t = xs_transaction_start(ctx->xsh);
 
     libxl__xs_writev(gc, t, dom_path, ents);
+    if (info->type == LIBXL_DOMAIN_TYPE_HVM)
+        libxl__xs_writev(gc, t, dom_path, hvm_ents);
+
     libxl__xs_writev(gc, t, dom_path, local_ents);
     libxl__xs_writev(gc, t, vm_path, vms_ents);
 
@@ -356,16 +367,19 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
     /* read signature */
     int rc;
     int hvm, pae, superpages;
+    int no_incr_generationid;
     switch (info->type) {
     case LIBXL_DOMAIN_TYPE_HVM:
         hvm = 1;
         superpages = 1;
         pae = info->u.hvm.pae;
+        no_incr_generationid = info->u.hvm.no_incr_generationid;
         break;
     case LIBXL_DOMAIN_TYPE_PV:
         hvm = 0;
         superpages = 0;
         pae = 1;
+        no_incr_generationid = 0;
         break;
     default:
         return ERROR_INVAL;
@@ -373,7 +387,8 @@ int libxl__domain_restore_common(libxl__gc *gc, uint32_t domid,
     rc = xc_domain_restore(ctx->xch, fd, domid,
                            state->store_port, &state->store_mfn,
                            state->console_port, &state->console_mfn,
-                           hvm, pae, superpages);
+                           hvm, pae, superpages, no_incr_generationid,
+                           &state->vm_generationid_addr);
     if ( rc ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "restoring domain");
         return ERROR_FAIL;
@@ -538,12 +553,23 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
     struct save_callbacks callbacks;
     struct suspendinfo si;
     int hvm, rc = ERROR_FAIL;
+    unsigned long vm_generationid_addr;
 
     switch (type) {
-    case LIBXL_DOMAIN_TYPE_HVM:
+    case LIBXL_DOMAIN_TYPE_HVM: {
+        char *path;
+        char *addr;
+
+        path = libxl__sprintf(gc, "%s/hvmloader/generation-id-address",
+                              libxl__xs_get_dompath(gc, domid));
+        addr = libxl__xs_read(gc, XBT_NULL, path);
+
+        vm_generationid_addr = (addr) ? strtoul(addr, NULL, 0) : 0;
         hvm = 1;
         break;
+    }
     case LIBXL_DOMAIN_TYPE_PV:
+        vm_generationid_addr = 0;
         hvm = 0;
         break;
     default:
@@ -581,7 +607,8 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
     callbacks.switch_qemu_logdirty = libxl__domain_suspend_common_switch_qemu_logdirty;
     callbacks.data = &si;
 
-    rc = xc_domain_save(ctx->xch, fd, domid, 0, 0, flags, &callbacks, hvm);
+    rc = xc_domain_save(ctx->xch, fd, domid, 0, 0, flags, &callbacks,
+                        hvm, vm_generationid_addr);
     if ( rc ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "saving domain: %s",
                          si.guest_responded ?

diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 070bae15c36c2ea175f2fe0dc1a5786dca3cf9aa..288c03cbde0019a08294f02fa5ea2989d2159ff4 100644 (file)
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -223,6 +223,7 @@ typedef struct {
 
     uint32_t console_port;
     unsigned long console_mfn;
+    unsigned long vm_generationid_addr;
 } libxl__domain_build_state;
 
 _hidden int libxl__build_pre(libxl__gc *gc, uint32_t domid,

diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 78a1cc6c45d3b417446c8c916791aa5ebff26264..574dec752a9cae668264144f8175651210a2276e 100644 (file)
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -184,6 +184,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
                                        ("vpt_align", bool),
                                        ("timer_mode", integer),
                                        ("nested_hvm", bool),
+                                       ("no_incr_generationid", bool),
                                        ])),
                  ("pv", Struct(None, [("kernel", libxl_file_reference),
                                       ("slack_memkb", uint32),

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 8da8b88a3313eda45af88de35eb0a3f4538a9885..8c30de188491808af6b01fc046603e0652bc6fd4 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -360,6 +360,8 @@ static void printf_info(int domid,
         printf("\t\t\t(vpt_align %d)\n", b_info->u.hvm.vpt_align);
         printf("\t\t\t(timer_mode %d)\n", b_info->u.hvm.timer_mode);
         printf("\t\t\t(nestedhvm %d)\n", b_info->u.hvm.nested_hvm);
+        printf("\t\t\t(no_incr_generationid %d)\n",
+                    b_info->u.hvm.no_incr_generationid);
 
         printf("\t\t\t(device_model %s)\n", dm_info->device_model ? : "default");
         printf("\t\t\t(videoram %d)\n", dm_info->videoram);
@@ -1364,6 +1366,7 @@ struct domain_create {
     const char *restore_file;
     int migrate_fd; /* -1 means none */
     char **migration_domname_r; /* from malloc */
+    int no_incr_generationid;
 };
 
 static int freemem(libxl_domain_build_info *b_info, libxl_device_model_info *dm_info)
@@ -1577,6 +1580,8 @@ static int create_domain(struct domain_create *dom_info)
         }
     }
 
+    d_config.b_info.u.hvm.no_incr_generationid = dom_info->no_incr_generationid;
+
     if (debug || dom_info->dryrun)
         printf_info(-1, &d_config, &d_config.dm_info);
 
@@ -2817,6 +2822,7 @@ static void migrate_receive(int debug, int daemonize, int monitor)
     dom_info.restore_file = "incoming migration stream";
     dom_info.migrate_fd = 0; /* stdin */
     dom_info.migration_domname_r = &migration_domname;
+    dom_info.no_incr_generationid = 1;
 
     rc = create_domain(&dom_info);
     if (rc < 0) {

diff --git a/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c b/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c
index aefc1cb31bab72899f83f4eeba3aad3f8563a004..0fc433fcf907f5063dd484b51f63908b505bc531 100644 (file)
--- a/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c
+++ b/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c
@@ -175,6 +175,7 @@ int checkpoint_start(checkpoint_state* s, int fd,
 {
     int hvm, rc;
     int flags = XCFLAGS_LIVE;
+    unsigned long vm_generationid_addr;
 
     if (!s->domid) {
        s->errstr = "checkpoint state not opened";
@@ -185,16 +186,28 @@ int checkpoint_start(checkpoint_state* s, int fd,
 
     hvm = s->domtype > dt_pv;
     if (hvm) {
+       char path[128];
+       char *addr;
+
+       sprintf(path, "/local/domain/%u/hvmloader/generation-id-address", s->domid);
+       addr = xs_read(s->xsh, XBT_NULL, path, NULL);
+
+       vm_generationid_addr = (addr) ? strtoul(addr, NULL, 0) : 0;
+       free(addr);
+
        flags |= XCFLAGS_HVM;
        if (switch_qemu_logdirty(s, 1))
            return -1;
+    } else {
+       vm_generationid_addr = 0;
     }
     if (remus_flags & CHECKPOINT_FLAGS_COMPRESSION)
       flags |= XCFLAGS_CHECKPOINT_COMPRESS;
 
     callbacks->switch_qemu_logdirty = noop_switch_logdirty;
 
-    rc = xc_domain_save(s->xch, fd, s->domid, 0, 0, flags, callbacks, hvm);
+    rc = xc_domain_save(s->xch, fd, s->domid, 0, 0, flags, callbacks, hvm,
+                        vm_generationid_addr);
 
     if (hvm)
        switch_qemu_logdirty(s, 0);

diff --git a/tools/xcutils/xc_restore.c b/tools/xcutils/xc_restore.c
index 985cbecb11a2130c0d1d118461e86f783dc1ceaf..63d53a88b0ac3cbdb396594f03d8d20917d1f77a 100644 (file)
--- a/tools/xcutils/xc_restore.c
+++ b/tools/xcutils/xc_restore.c
@@ -46,7 +46,8 @@ main(int argc, char **argv)
            superpages = !!hvm;
 
     ret = xc_domain_restore(xch, io_fd, domid, store_evtchn, &store_mfn,
-                            console_evtchn, &console_mfn, hvm, pae, superpages);
+                            console_evtchn, &console_mfn, hvm, pae, superpages,
+                            0, NULL);
 
     if ( ret == 0 )
     {

diff --git a/tools/xcutils/xc_save.c b/tools/xcutils/xc_save.c
index debb1bb89eadb56f402c3113c1569e74931cfb94..252759ea95a36882bc1bf21c57e74374fee27a5b 100644 (file)
--- a/tools/xcutils/xc_save.c
+++ b/tools/xcutils/xc_save.c
@@ -208,7 +208,7 @@ main(int argc, char **argv)
     callbacks.suspend = suspend;
     callbacks.switch_qemu_logdirty = switch_qemu_logdirty;
     ret = xc_domain_save(si.xch, io_fd, si.domid, maxit, max_f, si.flags, 
-                         &callbacks, !!(si.flags & XCFLAGS_HVM));
+                         &callbacks, !!(si.flags & XCFLAGS_HVM), 0);
 
     if (si.suspend_evtchn > 0)
         xc_suspend_evtchn_release(si.xch, si.xce, si.domid, si.suspend_evtchn);