[Xen-devel] [PATCH v4] libxc: check for various libxc failures and pass them down

[Matthew Daley <mattjd@xxxxxxxxx>]

...in xc_cpuid_{pv,hvm}_policy.

Coverity-ID: 1093050
Signed-off-by: Matthew Daley <mattjd@xxxxxxxxx>
---
v2: Return actual error from xc_domain_get_guest_width

v3: Return actual error from xc_cpuid_pv_policy as well, and add error
checking to libxc calls in xc_cpuid_hvm_param as well

v4: Use 'rc != 0' instead of just 'rc' in if checks

 tools/libxc/xc_cpuid_x86.c |   43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index bbbf9b8..8373e73 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -268,28 +268,35 @@ static void xc_cpuid_config_xsave(
     }
 }
 
-static void xc_cpuid_hvm_policy(
+static int xc_cpuid_hvm_policy(
     xc_interface *xch, domid_t domid,
     const unsigned int *input, unsigned int *regs)
 {
     DECLARE_DOMCTL;
+    int rc;
     char brand[13];
     unsigned long nestedhvm;
     unsigned long pae;
     int is_pae, is_nestedhvm;
     uint64_t xfeature_mask;
 
-    xc_get_hvm_param(xch, domid, HVM_PARAM_PAE_ENABLED, &pae);
+    rc = xc_get_hvm_param(xch, domid, HVM_PARAM_PAE_ENABLED, &pae);
+    if ( rc != 0 )
+        return rc;
     is_pae = !!pae;
 
     /* Detecting Xen's atitude towards XSAVE */
     memset(&domctl, 0, sizeof(domctl));
     domctl.cmd = XEN_DOMCTL_getvcpuextstate;
     domctl.domain = domid;
-    do_domctl(xch, &domctl);
+    rc = do_domctl(xch, &domctl);
+    if ( rc != 0 )
+        return rc;
     xfeature_mask = domctl.u.vcpuextstate.xfeature_mask;
 
-    xc_get_hvm_param(xch, domid, HVM_PARAM_NESTEDHVM, &nestedhvm);
+    rc = xc_get_hvm_param(xch, domid, HVM_PARAM_NESTEDHVM, &nestedhvm);
+    if ( rc != 0 )
+        return rc;
     is_nestedhvm = !!nestedhvm;
 
     switch ( input[0] )
@@ -429,13 +436,15 @@ static void xc_cpuid_hvm_policy(
     else
         intel_xc_cpuid_policy(xch, domid, input, regs, is_pae, is_nestedhvm);
 
+    return rc;
 }
 
-static void xc_cpuid_pv_policy(
+static int xc_cpuid_pv_policy(
     xc_interface *xch, domid_t domid,
     const unsigned int *input, unsigned int *regs)
 {
     DECLARE_DOMCTL;
+    int rc;
     unsigned int guest_width;
     int guest_64bit, xen_64bit = hypervisor_is_64bit(xch);
     char brand[13];
@@ -443,7 +452,9 @@ static void xc_cpuid_pv_policy(
 
     xc_cpuid_brand_get(brand);
 
-    xc_domain_get_guest_width(xch, domid, &guest_width);
+    rc = xc_domain_get_guest_width(xch, domid, &guest_width);
+    if ( rc != 0 )
+        return rc;
     guest_64bit = (guest_width == 8);
 
     /* Detecting Xen's atitude towards XSAVE */
@@ -547,23 +558,29 @@ static void xc_cpuid_pv_policy(
         regs[0] = regs[1] = regs[2] = regs[3] = 0;
         break;
     }
+
+    return rc;
 }
 
 static int xc_cpuid_policy(
     xc_interface *xch, domid_t domid,
     const unsigned int *input, unsigned int *regs)
 {
+    int                 rc;
     xc_dominfo_t        info;
 
-    if ( xc_domain_getinfo(xch, domid, 1, &info) == 0 )
+    rc = xc_domain_getinfo(xch, domid, 1, &info);
+    if ( rc < 0 )
+        return rc;
+    if ( rc == 0 )
         return -EINVAL;
 
     if ( info.hvm )
-        xc_cpuid_hvm_policy(xch, domid, input, regs);
+        rc = xc_cpuid_hvm_policy(xch, domid, input, regs);
     else
-        xc_cpuid_pv_policy(xch, domid, input, regs);
+        rc = xc_cpuid_pv_policy(xch, domid, input, regs);
 
-    return 0;
+    return rc;
 }
 
 static int xc_cpuid_do_domctl(
@@ -632,12 +649,14 @@ int xc_cpuid_apply_policy(xc_interface *xch, domid_t 
domid)
     for ( ; ; )
     {
         cpuid(input, regs);
-        xc_cpuid_policy(xch, domid, input, regs);
+        rc = xc_cpuid_policy(xch, domid, input, regs);
+        if ( rc != 0 )
+            return rc;
 
         if ( regs[0] || regs[1] || regs[2] || regs[3] )
         {
             rc = xc_cpuid_do_domctl(xch, domid, input, regs);
-            if ( rc )
+            if ( rc != 0 )
                 return rc;
         }
 
-- 
1.7.10.4


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