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Re: [Xen-devel] [PATCH Remus v1 4/8] tools/libxc: split read/handle qemu info





On 05/07/2015 06:48 PM, Andrew Cooper wrote:
On 07/05/15 07:37, Yang Hongyang wrote:
Split read/handle qemu info. The receiving of qemu info
should be done while we receive the migration stream,
handle_qemu will be called when the stream complete.
Otherwise, it will break Remus because read_record()
won't read qemu info and stream_complete will be called
at failover.

Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>

I presume this is because Remus sends multiple qemu records in the stream?

I will be fixing the qemu record layer violation as part of libxl
migration v2, at which point all the XG_LIBXL_HVM_COMPAT code shall
disappear.

ye, this patch should disappear with your fix :)


As all this code appears to live inside XG_LIBXL_HVM_COMPAT, I am
willing to trust that it DoesTheRightThing, if you have confirmed that
plain HVM migration with migration v2 and XG_LIBXL_HVM_COMPAT continues
to work (I am slightly suspicious of the 3rd hunk in this regard).

I tested both pv&hvm, normal migration are all work as it is.


~Andrew

---
  tools/libxc/xc_sr_common.h          |  5 +++++
  tools/libxc/xc_sr_restore.c         | 12 ++++++++++++
  tools/libxc/xc_sr_restore_x86_hvm.c | 28 +++++++++++++++++++++++++---
  3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/tools/libxc/xc_sr_common.h b/tools/libxc/xc_sr_common.h
index ef42412..6f099b8 100644
--- a/tools/libxc/xc_sr_common.h
+++ b/tools/libxc/xc_sr_common.h
@@ -279,6 +279,11 @@ struct xc_sr_context
                      /* HVM context blob. */
                      void *context;
                      size_t contextsz;
+
+#ifdef XG_LIBXL_HVM_COMPAT
+                    uint32_t qlen;
+                    void *qbuf;
+#endif
                  } restore;
              };
          } x86_hvm;
diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
index 53bd674..8022c3d 100644
--- a/tools/libxc/xc_sr_restore.c
+++ b/tools/libxc/xc_sr_restore.c
@@ -510,6 +510,9 @@ static int process_record(struct xc_sr_context *ctx, struct 
xc_sr_record *rec)
      return rc;
  }

+#ifdef XG_LIBXL_HVM_COMPAT
+extern int read_qemu(struct xc_sr_context *ctx);
+#endif
  /*
   * Restore a domain.
   */
@@ -546,6 +549,15 @@ static int restore(struct xc_sr_context *ctx)

      } while ( rec.type != REC_TYPE_END );

+#ifdef XG_LIBXL_HVM_COMPAT
+    if ( ctx->dominfo.hvm )
+    {
+        rc = read_qemu(ctx);
+        if ( rc )
+            goto err;
+    }
+#endif
+
      rc = ctx->restore.ops.stream_complete(ctx);
      if ( rc )
          goto err;
diff --git a/tools/libxc/xc_sr_restore_x86_hvm.c 
b/tools/libxc/xc_sr_restore_x86_hvm.c
index 6e9b318..6f5af0e 100644
--- a/tools/libxc/xc_sr_restore_x86_hvm.c
+++ b/tools/libxc/xc_sr_restore_x86_hvm.c
@@ -94,14 +94,14 @@ static int handle_hvm_params(struct xc_sr_context *ctx,
  }

  #ifdef XG_LIBXL_HVM_COMPAT
-static int handle_qemu(struct xc_sr_context *ctx)
+int read_qemu(struct xc_sr_context *ctx);
+int read_qemu(struct xc_sr_context *ctx)
  {
      xc_interface *xch = ctx->xch;
-    char qemusig[21], path[256];
+    char qemusig[21];
      uint32_t qlen;
      void *qbuf = NULL;
      int rc = -1;
-    FILE *fp = NULL;

      if ( read_exact(ctx->fd, qemusig, sizeof(qemusig)) )
      {
@@ -137,6 +137,28 @@ static int handle_qemu(struct xc_sr_context *ctx)
          goto out;
      }

+    /* With Remus, this could be read many times */
+    if ( ctx->x86_hvm.restore.qbuf )
+        free(ctx->x86_hvm.restore.qbuf);
+    ctx->x86_hvm.restore.qbuf = qbuf;
+    ctx->x86_hvm.restore.qlen = qlen;
+    rc = 0;
+
+out:
+    if (rc)
+        free(qbuf);
+    return rc;
+}
+
+static int handle_qemu(struct xc_sr_context *ctx)
+{
+    xc_interface *xch = ctx->xch;
+    char path[256];
+    uint32_t qlen = ctx->x86_hvm.restore.qlen;
+    void *qbuf = ctx->x86_hvm.restore.qbuf;
+    int rc = -1;
+    FILE *fp = NULL;
+
      sprintf(path, XC_DEVICE_MODEL_RESTORE_FILE".%u", ctx->domid);
      fp = fopen(path, "wb");
      if ( !fp )

.


--
Thanks,
Yang.

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