hypervisor/xen/tools: Remove the XENMEM_get_oustanding_pages and provide the data via xc_phys_info

During the review of the patches it was noticed that there exists
a race wherein the 'free_memory' value consists of information from
two hypercalls. That is the XEN_SYSCTL_physinfo and XENMEM_get_outstanding_pages.

The free memory the host has available for guest is the difference between
the 'free_pages' (from XEN_SYSCTL_physinfo) and 'outstanding_pages'. As they
are two hypercalls many things can happen in between the execution of them.

This patch resolves this by eliminating the XENMEM_get_outstanding_pages
hypercall and providing the free_pages and outstanding_pages information
via the xc_phys_info structure.

It also removes the XSM hooks and adds locking as needed.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: Keir Fraser <keir.xen@gmail.com>

1 files changed, 1 insertions, 14 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index bc91fd5abf..ee1fa9cf8c 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3942,6 +3942,7 @@ int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
     physinfo->total_pages = xcphysinfo.total_pages;
     physinfo->free_pages = xcphysinfo.free_pages;
     physinfo->scrub_pages = xcphysinfo.scrub_pages;
+    physinfo->outstanding_pages = xcphysinfo.outstanding_pages;
     l = xc_sharing_freed_pages(ctx->xch);
     if (l == -ENOSYS) {
         l = 0;
@@ -4105,20 +4106,6 @@ libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int *nr)
     return ret;
 }
 
-uint64_t libxl_get_claiminfo(libxl_ctx *ctx)
-{
-    long l;
-
-    l = xc_domain_get_outstanding_pages(ctx->xch);
-    if (l < 0) {
-        LIBXL__LOG_ERRNOVAL(ctx, LIBXL__LOG_WARNING, l,
-                            "xc_domain_get_outstanding_pages failed.");
-        return ERROR_FAIL;
-    }
-    /* In pages */
-    return l;
-}
-
 const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
 {
     union {