[Xen-devel] [PATCH 1/7] libxc: fix uninitialized variable in xc_cpuid_pv_policy()

[Jennifer Herbert <Jennifer.Herbert@xxxxxxxxxx>]

If xc_domain_get_guest_width were to fail, guest_width is not set, and
hence guest_64bit becomes undefined.
Fix is to initialise to 0, and report error if call fails.

Signed-off-by: Jennifer Herbert <jennifer.herbert@xxxxxxxxxx>
---
 tools/libxc/xc_cpuid_x86.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index c97f91a..847b701 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -437,14 +437,16 @@ static void xc_cpuid_pv_policy(
 {
     DECLARE_DOMCTL;
     unsigned int guest_width;
-    int guest_64bit;
+    int guest_64bit = 0;
     char brand[13];
     uint64_t xfeature_mask;
 
     xc_cpuid_brand_get(brand);
 
-    xc_domain_get_guest_width(xch, domid, &guest_width);
-    guest_64bit = (guest_width == 8);
+    if (xc_domain_get_guest_width(xch, domid, &guest_width) == 0)
+        guest_64bit = (guest_width == 8);
+    else
+        ERROR("Could not read guest word width.");
 
     /* Detecting Xen's atitude towards XSAVE */
     memset(&domctl, 0, sizeof(domctl));
-- 
1.7.10.4


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