tools/libxc: Drop config_transformed parameter from xc_cpuid_set()

libxl is now the sole caller of xc_cpuid_set().  The config_transformed output
is ignored, and this patch trivially highlights the resulting memory leak.

"transformed" config is now properly forwarded on migrate as part of the
general VM state, so delete the transformation logic completely, rather than
trying to adjust just libxl to avoid leaking memory.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Release-acked-by: Paul Durrant <paul@xen.org>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/libxc/include/xenctrl.h

@@ -1795,8 +1795,7 @@ int xc_domain_debug_control(xc_interface *xch,
 int xc_cpuid_set(xc_interface *xch,
                  uint32_t domid,
                  const unsigned int *input,
-                 const char **config,
-                 char **config_transformed);
+                 const char **config);
 
 /*
  * Make adjustments to the CPUID settings for a domain.

tools/libxc/xc_cpuid_x86.c

@@ -279,7 +279,7 @@ int xc_set_domain_cpu_policy(xc_interface *xch, uint32_t domid,
  */
 int xc_cpuid_set(
     xc_interface *xch, uint32_t domid, const unsigned int *input,
-    const char **config, char **config_transformed)
+    const char **config)
 {
     int rc;
     unsigned int i, j, regs[4] = {}, polregs[4] = {};
@@ -288,9 +288,6 @@ int xc_cpuid_set(
     unsigned int nr_leaves, policy_leaves, nr_msrs;
     uint32_t err_leaf = -1, err_subleaf = -1, err_msr = -1;
 
-    for ( i = 0; i < 4; ++i )
-        config_transformed[i] = NULL;
-
     if ( xc_domain_getinfo(xch, domid, 1, &di) != 1 ||
          di.domid != domid )
     {
@@ -365,13 +362,6 @@ int xc_cpuid_set(
             continue;
         }
 
-        config_transformed[i] = calloc(33, 1); /* 32 bits, NUL terminator. */
-        if ( config_transformed[i] == NULL )
-        {
-            rc = -ENOMEM;
-            goto fail;
-        }
-
         /*
          * Notes for following this algorithm:
          *
@@ -399,11 +389,6 @@ int xc_cpuid_set(
                 set_feature(31 - j, regs[i]);
             else
                 clear_feature(31 - j, regs[i]);
-
-            config_transformed[i][j] = config[i][j];
-            /* All non 0/1 values get overwritten. */
-            if ( (config[i][j] & ~1) != '0' )
-                config_transformed[i][j] = '0' + val;
         }
     }
 
@@ -421,16 +406,8 @@ int xc_cpuid_set(
     }
 
     /* Success! */
-    goto out;
 
  fail:
-    for ( i = 0; i < 4; i++ )
-    {
-        free(config_transformed[i]);
-        config_transformed[i] = NULL;
-    }
-
- out:
     free(leaves);
 
     return rc;

tools/libxl/libxl_cpuid.c

@@ -421,7 +421,6 @@ void libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid,
 {
     libxl_cpuid_policy_list cpuid = info->cpuid;
     int i;
-    char *cpuid_res[4];
     bool pae = true;
 
     /*
@@ -444,7 +443,7 @@ void libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid,
 
     for (i = 0; cpuid[i].input[0] != XEN_CPUID_INPUT_UNUSED; i++)
         xc_cpuid_set(ctx->xch, domid, cpuid[i].input,
-                     (const char**)(cpuid[i].policy), cpuid_res);
+                     (const char**)cpuid[i].policy);
 }
 
 static const char *input_names[2] = { "leaf", "subleaf" };