[Xen-devel] [PATCH for-4.10 v2 5/5] tools/dombuilder: Prevent failures of xc_dom_gnttab_init()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Recent changes in grant table configuration have caused calls to
xc_dom_gnttab_init() to fail if not proceeded with a call to
xc_domain_set_gnttab_limits().  This is backwards from the point of view of
3rd party dombuilder users.

Add max_{grant,maptrack}_frames parameters to struct xc_dom_image, and require
them to be set by callers using xc_dom_gnttab_init().  Libxl, which uses
xc_dom_gnttab_init() itself is updated appropriately.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Tested-by: Julien Grall <julien.grall@xxxxxxx>
---
CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

v2:
 * Set errno to EINVAL if max_{grant,maptrack}_frames are not provided
---
 tools/libxc/include/xc_dom.h |  4 ++++
 tools/libxc/xc_dom_boot.c    | 16 ++++++++++++++++
 tools/libxc/xc_dom_core.c    |  3 +++
 tools/libxl/libxl_dom.c      | 12 ++++++------
 4 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/tools/libxc/include/xc_dom.h b/tools/libxc/include/xc_dom.h
index a1c3de2..5292424 100644
--- a/tools/libxc/include/xc_dom.h
+++ b/tools/libxc/include/xc_dom.h
@@ -116,6 +116,10 @@ struct xc_dom_image {
     uint32_t console_domid;
     uint32_t xenstore_domid;
 
+    /* Grant limit configuration; mandatory if calling xc_dom_gnttab_init(). */
+    unsigned int max_grant_frames;
+    unsigned int max_maptrack_frames;
+
     /*
      * initrd parameters as specified in start_info page
      * Depending on capabilities of the booted kernel this may be a virtual
diff --git a/tools/libxc/xc_dom_boot.c b/tools/libxc/xc_dom_boot.c
index 75836bd..7c21fea 100644
--- a/tools/libxc/xc_dom_boot.c
+++ b/tools/libxc/xc_dom_boot.c
@@ -420,6 +420,22 @@ int xc_dom_gnttab_hvm_seed(xc_interface *xch, uint32_t 
domid,
 
 int xc_dom_gnttab_init(struct xc_dom_image *dom)
 {
+    int rc;
+
+    if ( dom->max_grant_frames == -1 || dom->max_maptrack_frames == -1 )
+    {
+        xc_dom_panic(dom->xch, XC_INVALID_PARAM,
+                     "%s: Caller didn't set grant limit information", 
__func__);
+        errno = EINVAL;
+
+        return -1;
+    }
+
+    if ( (rc = xc_domain_set_gnttab_limits(dom->xch, dom->guest_domid,
+                                           dom->max_grant_frames,
+                                           dom->max_maptrack_frames)) != 0 )
+        return rc;
+
     if ( xc_dom_translated(dom) ) {
         return xc_dom_gnttab_hvm_seed(dom->xch, dom->guest_domid,
                                       dom->console_gfn, dom->xenstore_gfn,
diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
index 7087c50..d660651 100644
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -784,6 +784,9 @@ struct xc_dom_image *xc_dom_allocate(xc_interface *xch,
     dom->console_domid = INVALID_DOMID;
     dom->xenstore_domid = INVALID_DOMID;
 
+    dom->max_grant_frames = -1;
+    dom->max_maptrack_frames = -1;
+
     dom->flags = SIF_VIRT_P2M_4TOOLS;
 
     dom->alloc_malloc += sizeof(*dom);
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index fcdeef0..fa5319d 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -358,12 +358,6 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
         return ERROR_FAIL;
     }
 
-    if (xc_domain_set_gnttab_limits(ctx->xch, domid, info->max_grant_frames,
-                                    info->max_maptrack_frames) != 0) {
-        LOG(ERROR, "Couldn't set grant table limits");
-        return ERROR_FAIL;
-    }
-
     /*
      * Check if the domain has any CPU or node affinity already. If not, try
      * to build up the latter via automatic NUMA placement. In fact, in case
@@ -815,6 +809,9 @@ int libxl__build_pv(libxl__gc *gc, uint32_t domid,
     dom->xenstore_domid = state->store_domid;
     dom->claim_enabled = libxl_defbool_val(info->claim_mode);
 
+    dom->max_grant_frames    = info->max_grant_frames;
+    dom->max_maptrack_frames = info->max_maptrack_frames;
+
     if (info->num_vnuma_nodes != 0) {
         unsigned int i;
 
@@ -1151,6 +1148,9 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
     dom->xenstore_evtchn = state->store_port;
     dom->xenstore_domid = state->store_domid;
 
+    dom->max_grant_frames    = info->max_grant_frames;
+    dom->max_maptrack_frames = info->max_maptrack_frames;
+
     /* The params from the configuration file are in Mb, which are then
      * multiplied by 1 Kb. This was then divided off when calling
      * the old xc_hvm_build_target_mem() which then turned them to bytes.
-- 
2.1.4


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