[PATCH v2 3/6] libxc/migration: Be rather stricter with illformed callers

[Andrew Cooper <andrew.cooper3@citrix.com>]

The migration code itself should be able to validly assume all mandatory
callbacks are set up.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Yang Hongyang <yanghy@cn.fujitsu.com>
---
 tools/libxc/xc_sr_save.c         |    4 ++++
 tools/libxc/xc_sr_save_x86_hvm.c |    7 -------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
index 5d9c267..83f0591 100644
--- a/tools/libxc/xc_sr_save.c
+++ b/tools/libxc/xc_sr_save.c
@@ -738,6 +738,10 @@ int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t dom,
     ctx.save.max_iterations = 5;
     ctx.save.dirty_threshold = 50;
 
+    /* Sanity checks for callbacks. */
+    if ( hvm )
+        assert(callbacks->switch_qemu_logdirty);
+
     IPRINTF("In experimental %s", __func__);
     DPRINTF("fd %d, dom %u, max_iters %u, max_factor %u, flags %u, hvm %d",
             io_fd, dom, max_iters, max_factor, flags, hvm);
diff --git a/tools/libxc/xc_sr_save_x86_hvm.c b/tools/libxc/xc_sr_save_x86_hvm.c
index 8baa104..58efdb9 100644
--- a/tools/libxc/xc_sr_save_x86_hvm.c
+++ b/tools/libxc/xc_sr_save_x86_hvm.c
@@ -166,13 +166,6 @@ static int x86_hvm_setup(struct xc_sr_context *ctx)
 {
     xc_interface *xch = ctx->xch;
 
-    if ( !ctx->save.callbacks->switch_qemu_logdirty )
-    {
-        ERROR("No switch_qemu_logdirty callback provided");
-        errno = EINVAL;
-        return -1;
-    }
-
     if ( ctx->save.callbacks->switch_qemu_logdirty(
              ctx->domid, 1, ctx->save.callbacks->data) )
     {
-- 
1.7.10.4