diff mbox series

[v5,09/12] libs/guest: apply a featureset into a cpu policy

Message ID 20211129153355.60338-10-roger.pau@citrix.com (mailing list archive)
State Superseded
Headers show
Series libs/guest: new CPUID/MSR interface | expand

Commit Message

Roger Pau Monné Nov. 29, 2021, 3:33 p.m. UTC
Pull out the code from xc_cpuid_apply_policy that applies a featureset
to a cpu policy and place it on it's own standalone function that's
part of the public interface.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
 tools/include/xenguest.h        |  5 ++
 tools/libs/guest/xg_cpuid_x86.c | 95 ++++++++++++++++++++-------------
 2 files changed, 62 insertions(+), 38 deletions(-)

Comments

Jan Beulich Dec. 6, 2021, 4:19 p.m. UTC | #1
On 29.11.2021 16:33, Roger Pau Monne wrote:
> Pull out the code from xc_cpuid_apply_policy that applies a featureset
> to a cpu policy and place it on it's own standalone function that's
> part of the public interface.
> 
> No functional change intended.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>
diff mbox series

Patch

diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h
index 9912116a51..8f05d8aa66 100644
--- a/tools/include/xenguest.h
+++ b/tools/include/xenguest.h
@@ -829,6 +829,11 @@  int xc_cpu_policy_legacy_topology(xc_interface *xch, xc_cpu_policy_t *policy,
 int xc_cpu_policy_apply_cpuid(xc_interface *xch, xc_cpu_policy_t *policy,
                               const struct xc_xend_cpuid *cpuid, bool hvm);
 
+/* Apply a featureset to the policy. */
+int xc_cpu_policy_apply_featureset(xc_interface *xch, xc_cpu_policy_t *policy,
+                                   const uint32_t *featureset,
+                                   unsigned int nr_features);
+
 int xc_get_cpu_levelling_caps(xc_interface *xch, uint32_t *caps);
 int xc_get_cpu_featureset(xc_interface *xch, uint32_t index,
                           uint32_t *nr_features, uint32_t *featureset);
diff --git a/tools/libs/guest/xg_cpuid_x86.c b/tools/libs/guest/xg_cpuid_x86.c
index 121bce1a92..41c6e66b6f 100644
--- a/tools/libs/guest/xg_cpuid_x86.c
+++ b/tools/libs/guest/xg_cpuid_x86.c
@@ -443,46 +443,15 @@  int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid, bool restore,
 
     if ( featureset )
     {
-        uint32_t disabled_features[FEATURESET_NR_ENTRIES],
-            feat[FEATURESET_NR_ENTRIES] = {};
-        static const uint32_t deep_features[] = INIT_DEEP_FEATURES;
-        unsigned int i, b;
-
-        /*
-         * The user supplied featureset may be shorter or longer than
-         * FEATURESET_NR_ENTRIES.  Shorter is fine, and we will zero-extend.
-         * Longer is fine, so long as it only padded with zeros.
-         */
-        unsigned int user_len = min(FEATURESET_NR_ENTRIES + 0u, nr_features);
-
-        /* Check for truncated set bits. */
-        rc = -EOPNOTSUPP;
-        for ( i = user_len; i < nr_features; ++i )
-            if ( featureset[i] != 0 )
-                goto out;
-
-        memcpy(feat, featureset, sizeof(*featureset) * user_len);
-
-        /* Disable deep dependencies of disabled features. */
-        for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
-            disabled_features[i] = ~feat[i] & deep_features[i];
-
-        for ( b = 0; b < sizeof(disabled_features) * CHAR_BIT; ++b )
+        policy.cpuid = *p;
+        rc = xc_cpu_policy_apply_featureset(xch, &policy, featureset,
+                                            nr_features);
+        if ( rc )
         {
-            const uint32_t *dfs;
-
-            if ( !test_bit(b, disabled_features) ||
-                 !(dfs = x86_cpuid_lookup_deep_deps(b)) )
-                continue;
-
-            for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
-            {
-                feat[i] &= ~dfs[i];
-                disabled_features[i] &= ~dfs[i];
-            }
+            ERROR("Failed to apply featureset to policy");
+            goto out;
         }
-
-        cpuid_featureset_to_policy(feat, p);
+        *p = policy.cpuid;
     }
     else
     {
@@ -918,3 +887,53 @@  int xc_cpu_policy_legacy_topology(xc_interface *xch, xc_cpu_policy_t *policy,
 
     return 0;
 }
+
+int xc_cpu_policy_apply_featureset(xc_interface *xch, xc_cpu_policy_t *policy,
+                                   const uint32_t *featureset,
+                                   unsigned int nr_features)
+{
+    uint32_t disabled_features[FEATURESET_NR_ENTRIES],
+        feat[FEATURESET_NR_ENTRIES] = {};
+    static const uint32_t deep_features[] = INIT_DEEP_FEATURES;
+    unsigned int i, b;
+
+    /*
+     * The user supplied featureset may be shorter or longer than
+     * FEATURESET_NR_ENTRIES.  Shorter is fine, and we will zero-extend.
+     * Longer is fine, so long as it only padded with zeros.
+     */
+    unsigned int user_len = min(FEATURESET_NR_ENTRIES + 0u, nr_features);
+
+    /* Check for truncated set bits. */
+    for ( i = user_len; i < nr_features; ++i )
+        if ( featureset[i] != 0 )
+        {
+            errno = EOPNOTSUPP;
+            return -1;
+        }
+
+    memcpy(feat, featureset, sizeof(*featureset) * user_len);
+
+    /* Disable deep dependencies of disabled features. */
+    for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
+        disabled_features[i] = ~feat[i] & deep_features[i];
+
+    for ( b = 0; b < sizeof(disabled_features) * CHAR_BIT; ++b )
+    {
+        const uint32_t *dfs;
+
+        if ( !test_bit(b, disabled_features) ||
+             !(dfs = x86_cpuid_lookup_deep_deps(b)) )
+            continue;
+
+        for ( i = 0; i < ARRAY_SIZE(disabled_features); ++i )
+        {
+            feat[i] &= ~dfs[i];
+            disabled_features[i] &= ~dfs[i];
+        }
+    }
+
+    cpuid_featureset_to_policy(feat, &policy->cpuid);
+
+    return 0;
+}