[PATCH RFC 13/31] tools/libxc: Wire a featureset through to cpuid policy logic

[Andrew Cooper <andrew.cooper3@citrix.com>]

Later changes will cause the cpuid generation logic to seed their information
from a featureset.  This patch adds the infrastructure to specify a
featureset, and will obtain the appropriate default from Xen if omitted.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxc/include/xenctrl.h |  3 ++
 tools/libxc/xc_cpuid_x86.c    | 90 ++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 84 insertions(+), 9 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 27e1f45..b44aec7 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2211,6 +2211,9 @@ int xc_cpuid_set(xc_interface *xch,
                  char **config_transformed);
 int xc_cpuid_apply_policy(xc_interface *xch,
                           domid_t domid);
+int xc_cpuid_apply_policy_with_featureset(xc_interface *xch, domid_t domid,
+                                          uint32_t *featureset,
+                                          unsigned int nr_features);
 void xc_cpuid_to_str(const unsigned int *regs,
                      char **strs); /* some strs[] may be NULL if ENOMEM */
 int xc_mca_op(xc_interface *xch, struct xen_mc *mc);
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index 0a806cb..8bd3126 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -46,6 +46,9 @@ struct cpuid_domain_info
     bool pvh;
     uint64_t xfeature_mask;
 
+    uint32_t *featureset;
+    unsigned int nr_features;
+
     /* PV-only information. */
     bool pv64;
 
@@ -77,11 +80,14 @@ static void cpuid(const unsigned int *input, unsigned int *regs)
 }
 
 static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
-                                 struct cpuid_domain_info *info)
+                                 struct cpuid_domain_info *info,
+                                 uint32_t *featureset,
+                                 unsigned int nr_features)
 {
     struct xen_domctl domctl = {};
     xc_dominfo_t di;
     unsigned int in[2] = { 0, ~0U }, regs[4];
+    unsigned int i, host_nr_features = 0;
     int rc;
 
     cpuid(in, regs);
@@ -103,6 +109,32 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
     info->hvm = di.hvm;
     info->pvh = di.pvh;
 
+    /* Get featureset information. */
+    rc = xc_get_featureset(xch, XEN_SYSCTL_featureset_host,
+                           &host_nr_features, NULL);
+    if ( rc )
+        return rc;
+
+    if ( host_nr_features < XEN_FEATURESET_7c0 )
+        return -EINVAL;
+
+    info->featureset = calloc(host_nr_features, sizeof(*info->featureset));
+    if ( !info->featureset )
+        return -ENOMEM;
+
+    info->nr_features = host_nr_features;
+
+    if ( featureset )
+    {
+        memcpy(info->featureset, featureset,
+               min(host_nr_features, nr_features) * sizeof(*info->featureset));
+
+        /* Check for trucated set bits. */
+        for ( i = nr_features; i < host_nr_features; ++i )
+            if ( featureset[i] != 0 )
+                return -EOPNOTSUPP;
+    }
+
     /* Get xstate information. */
     domctl.cmd = XEN_DOMCTL_getvcpuextstate;
     domctl.domain = domid;
@@ -127,6 +159,14 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
             return rc;
 
         info->nestedhvm = !!val;
+
+        if ( !featureset )
+        {
+            rc = xc_get_featureset(xch, XEN_SYSCTL_featureset_hvm,
+                                   &host_nr_features, info->featureset);
+            if ( rc )
+                return rc;
+        }
     }
     else
     {
@@ -137,11 +177,24 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
             return rc;
 
         info->pv64 = (width == 8);
+
+        if ( !featureset )
+        {
+            rc = xc_get_featureset(xch, XEN_SYSCTL_featureset_pv,
+                                   &host_nr_features, info->featureset);
+            if ( rc )
+                return rc;
+        }
     }
 
     return 0;
 }
 
+static void free_cpuid_domain_info(struct cpuid_domain_info *info)
+{
+    free(info->featureset);
+}
+
 static void amd_xc_cpuid_policy(xc_interface *xch,
                                 const struct cpuid_domain_info *info,
                                 const unsigned int *input, unsigned int *regs)
@@ -653,16 +706,18 @@ void xc_cpuid_to_str(const unsigned int *regs, char **strs)
     }
 }
 
-int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
+static int __xc_cpuid_apply_policy(xc_interface *xch, domid_t domid,
+                                   uint32_t *featureset,
+                                   unsigned int nr_features)
 {
     struct cpuid_domain_info info = {};
     unsigned int input[2] = { 0, 0 }, regs[4];
     unsigned int base_max, ext_max;
     int rc;
 
-    rc = get_cpuid_domain_info(xch, domid, &info);
+    rc = get_cpuid_domain_info(xch, domid, &info, featureset, nr_features);
     if ( rc )
-        return rc;
+        goto out;
 
     cpuid(input, regs);
     base_max = (regs[0] <= DEF_MAX_BASE) ? regs[0] : DEF_MAX_BASE;
@@ -685,7 +740,7 @@ int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
         {
             rc = xc_cpuid_do_domctl(xch, domid, input, regs);
             if ( rc )
-                return rc;
+                goto out;
         }
 
         /* Intel cache descriptor leaves. */
@@ -713,7 +768,21 @@ int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
             break;
     }
 
-    return 0;
+ out:
+    free_cpuid_domain_info(&info);
+    return rc;
+}
+
+int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
+{
+    return __xc_cpuid_apply_policy(xch, domid, NULL, 0);
+}
+
+int xc_cpuid_apply_policy_with_featureset(xc_interface *xch, domid_t domid,
+                                          uint32_t *featureset,
+                                          unsigned int nr_features)
+{
+    return __xc_cpuid_apply_policy(xch, domid, featureset, nr_features);
 }
 
 /*
@@ -802,9 +871,9 @@ int xc_cpuid_set(
 
     memset(config_transformed, 0, 4 * sizeof(*config_transformed));
 
-    rc = get_cpuid_domain_info(xch, domid, &info);
+    rc = get_cpuid_domain_info(xch, domid, &info, NULL, 0);
     if ( rc )
-        return rc;
+        goto out;
 
     cpuid(input, regs);
 
@@ -855,7 +924,7 @@ int xc_cpuid_set(
 
     rc = xc_cpuid_do_domctl(xch, domid, input, regs);
     if ( rc == 0 )
-        return 0;
+        goto out;
 
  fail:
     for ( i = 0; i < 4; i++ )
@@ -863,5 +932,8 @@ int xc_cpuid_set(
         free(config_transformed[i]);
         config_transformed[i] = NULL;
     }
+
+ out:
+    free_cpuid_domain_info(&info);
     return rc;
 }
-- 
2.1.4