[PATCH v2 28/30] 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>

v2:
 * Modify existing call rather than introducing a new one.
 * Fix up in-tree callsites.
---
 tools/libxc/include/xenctrl.h       |  4 ++-
 tools/libxc/xc_cpuid_x86.c          | 69 ++++++++++++++++++++++++++++++++-----
 tools/libxl/libxl_cpuid.c           |  2 +-
 tools/ocaml/libs/xc/xenctrl_stubs.c |  2 +-
 tools/python/xen/lowlevel/xc/xc.c   |  2 +-
 5 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 1da372d..230f834 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1927,7 +1927,9 @@ int xc_cpuid_set(xc_interface *xch,
                  const char **config,
                  char **config_transformed);
 int xc_cpuid_apply_policy(xc_interface *xch,
-                          domid_t domid);
+                          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 7ef37d2..e762d73 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -148,6 +148,9 @@ struct cpuid_domain_info
     bool pvh;
     uint64_t xfeature_mask;
 
+    uint32_t *featureset;
+    unsigned int nr_features;
+
     /* PV-only information. */
     bool pv64;
 
@@ -179,11 +182,14 @@ 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 = xc_get_cpu_featureset_size();
     int rc;
 
     cpuid(in, regs);
@@ -205,6 +211,23 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
     info->hvm = di.hvm;
     info->pvh = di.pvh;
 
+    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 truncated 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;
@@ -229,6 +252,14 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
             return rc;
 
         info->nestedhvm = !!val;
+
+        if ( !featureset )
+        {
+            rc = xc_get_cpu_featureset(xch, XEN_SYSCTL_cpu_featureset_hvm,
+                                       &host_nr_features, info->featureset);
+            if ( rc )
+                return rc;
+        }
     }
     else
     {
@@ -239,11 +270,24 @@ static int get_cpuid_domain_info(xc_interface *xch, domid_t domid,
             return rc;
 
         info->pv64 = (width == 8);
+
+        if ( !featureset )
+        {
+            rc = xc_get_cpu_featureset(xch, XEN_SYSCTL_cpu_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)
@@ -764,16 +808,18 @@ void xc_cpuid_to_str(const unsigned int *regs, char **strs)
     }
 }
 
-int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
+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;
@@ -796,7 +842,7 @@ 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. */
@@ -824,7 +870,9 @@ int xc_cpuid_apply_policy(xc_interface *xch, domid_t domid)
             break;
     }
 
-    return 0;
+ out:
+    free_cpuid_domain_info(&info);
+    return rc;
 }
 
 /*
@@ -913,9 +961,9 @@ 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);
 
@@ -966,7 +1014,7 @@ 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++ )
@@ -974,5 +1022,8 @@ int xc_cpuid_set(
         free(config_transformed[i]);
         config_transformed[i] = NULL;
     }
+
+ out:
+    free_cpuid_domain_info(&info);
     return rc;
 }
diff --git a/tools/libxl/libxl_cpuid.c b/tools/libxl/libxl_cpuid.c
index c66e912..fc20157 100644
--- a/tools/libxl/libxl_cpuid.c
+++ b/tools/libxl/libxl_cpuid.c
@@ -334,7 +334,7 @@ int libxl_cpuid_parse_config_xend(libxl_cpuid_policy_list *cpuid,
 
 void libxl_cpuid_apply_policy(libxl_ctx *ctx, uint32_t domid)
 {
-    xc_cpuid_apply_policy(ctx->xch, domid);
+    xc_cpuid_apply_policy(ctx->xch, domid, NULL, 0);
 }
 
 void libxl_cpuid_set(libxl_ctx *ctx, uint32_t domid,
diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c b/tools/ocaml/libs/xc/xenctrl_stubs.c
index e7adf37..5477df3 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -796,7 +796,7 @@ CAMLprim value stub_xc_domain_cpuid_apply_policy(value xch, value domid)
 #if defined(__i386__) || defined(__x86_64__)
 	int r;
 
-	r = xc_cpuid_apply_policy(_H(xch), _D(domid));
+	r = xc_cpuid_apply_policy(_H(xch), _D(domid), NULL, 0);
 	if (r < 0)
 		failwith_xc(_H(xch));
 #else
diff --git a/tools/python/xen/lowlevel/xc/xc.c b/tools/python/xen/lowlevel/xc/xc.c
index c40a4e9..22a1c9f 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -731,7 +731,7 @@ static PyObject *pyxc_dom_set_policy_cpuid(XcObject *self,
     if ( !PyArg_ParseTuple(args, "i", &domid) )
         return NULL;
 
-    if ( xc_cpuid_apply_policy(self->xc_handle, domid) )
+    if ( xc_cpuid_apply_policy(self->xc_handle, domid, NULL, 0) )
         return pyxc_error_to_exception(self->xc_handle);
 
     Py_INCREF(zero);
-- 
2.1.4