[Xen-devel] [PATCH v4 11/24] x86: refactor psr: set value: implement cos id allocation flow.

[Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>]

Continue with previous patches, if fail to find a COS ID, we need allocate
a new COS ID for domain. Only COS ID that ref[COS_ID] is 1 or 0 can be
allocated to input a new set feature values.

Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/psr.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 104 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index 6b2b1e0..ac98c39 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -169,6 +169,23 @@ struct feat_ops {
      */
     int (*compare_val)(const uint64_t val[], const struct feat_node *feat,
                         unsigned int cos, bool *found);
+    /*
+     * exceeds_cos_max is used to check if the input cos id exceeds the
+     * feature's cos_max and if the input value is not the default one.
+     * Even if the associated cos exceeds the cos_max, HW can work with default
+     * value. That is the reason we need check if input value is default one.
+     * If both criteria are fulfilled, that means the input exceeds the
+     * range.
+     *
+     * The return value of the function means the number of the value array
+     * entries to skip or error.
+     * 1 - one entry in value array.
+     * 2 - two entries in value array, e.g. CDP uses two entries.
+     * 0 - error, exceed cos_max and the input value is not default.
+     */
+    unsigned int (*exceeds_cos_max)(const uint64_t val[],
+                                    const struct feat_node *feat,
+                                    unsigned int cos);
 };
 
 
@@ -402,6 +419,28 @@ static int l3_cat_compare_val(const uint64_t val[],
     /* L3 CAT uses one COS. */
     return 1;
 }
+
+static unsigned int l3_cat_exceeds_cos_max(const uint64_t val[],
+                                           const struct feat_node *feat,
+                                           unsigned int cos)
+{
+    uint64_t l3_def_cbm;
+
+    l3_def_cbm = (1ull << feat->info.l3_cat_info.cbm_len) - 1;
+
+    /* CAT */
+    if ( cos > feat->info.l3_cat_info.cos_max &&
+         val[0] != l3_def_cbm )
+            /*
+             * Exceed cos_max and value to set is not default,
+             * return error.
+             */
+            return 0;
+
+    /* L3 CAT uses one COS. */
+    return 1;
+}
+
 struct feat_ops l3_cat_ops = {
     .init_feature = l3_cat_init_feature,
     .get_max_cos_max = l3_cat_get_max_cos_max,
@@ -412,6 +451,7 @@ struct feat_ops l3_cat_ops = {
     .set_new_val = l3_cat_set_new_val,
     .get_cos_max_from_type = l3_cat_get_cos_max_from_type,
     .compare_val = l3_cat_compare_val,
+    .exceeds_cos_max = l3_cat_exceeds_cos_max,
 };
 
 static void __init parse_psr_bool(char *s, char *value, char *feature,
@@ -778,12 +818,75 @@ static int find_cos(const uint64_t *val, uint32_t 
array_len,
     return -ENOENT;
 }
 
+static bool exceeds_cos_max(const uint64_t *val,
+                            uint32_t array_len,
+                            const struct psr_socket_info *info,
+                            unsigned int cos)
+{
+    unsigned int ret;
+    const uint64_t *val_tmp = val;
+    const struct feat_node *feat_tmp;
+
+    list_for_each_entry(feat_tmp, &info->feat_list, list)
+    {
+        ret = feat_tmp->ops.exceeds_cos_max(val_tmp, feat_tmp, cos);
+        if ( !ret )
+            return false;
+
+        val_tmp += ret;
+        if ( val_tmp - val > array_len )
+            return false;
+    }
+
+    return true;
+}
+
 static int alloc_new_cos(const struct psr_socket_info *info,
                          const uint64_t *val, uint32_t array_len,
                          unsigned int old_cos,
                          enum cbm_type type)
 {
-    return 0;
+    unsigned int cos;
+    unsigned int cos_max = 0;
+    const struct feat_node *feat_tmp;
+    const unsigned int *ref = info->cos_ref;
+
+    /*
+     * cos_max is the one of the feature which is being set.
+     */
+    list_for_each_entry(feat_tmp, &info->feat_list, list)
+    {
+        cos_max = feat_tmp->ops.get_cos_max_from_type(feat_tmp, type);
+        if ( cos_max > 0 )
+            break;
+    }
+
+    if ( !cos_max )
+        return -ENOENT;
+
+    /*
+     * If old cos is referred only by the domain, then use it. And, we cannot
+     * use id 0 because it stores the default values.
+     */
+    if ( ref[old_cos] == 1 && old_cos )
+        if ( exceeds_cos_max(val, array_len, info, old_cos) )
+            return old_cos;
+
+    /* Find an unused one other than cos0. */
+    for ( cos = 1; cos <= cos_max; cos++ )
+        /*
+         * ref is 0 means this COS is not used by other domain and
+         * can be used for current setting.
+         */
+        if ( !ref[cos] )
+        {
+            if ( !exceeds_cos_max(val, array_len, info, cos) )
+                return -ENOENT;
+
+            return cos;
+        }
+
+    return -ENOENT;
 }
 
 static int write_psr_msr(unsigned int socket, unsigned int cos,
-- 
1.9.1


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