[PATCH v10 11/25] x86: refactor psr: L3 CAT: set value: implement cos finding flow.

[Yi Sun <yi.y.sun@linux.intel.com>]

Continue from patch:
'x86: refactor psr: L3 CAT: set value: assemble features value array'

We can try to find if there is a COS ID on which all features' COS registers
values are same as the array assembled before.

Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
---
v10:
    - remove 'compare_val' hook and its CAT implementation. Make its
      functionality be generic in 'find_cos' flow.
      (suggested by Jan Beulich)
    - changes related to 'props'.
      (suggested by Jan Beulich)
    - rename 'val_array' to 'val_ptr'.
      (suggested by Jan Beulich)
    - rename 'find' to 'found'.
      (suggested by Jan Beulich)
    - move some variables declaration and initialization into loop.
      (suggested by Jan Beulich)
    - adjust codes positions.
      (suggested by Jan Beulich)
v9:
    - modify comments of 'compare_val' to be same as current implementation.
      (suggested by Wei Liu)
    - fix indentation issue.
      (suggested by Wei Liu)
    - rename 'l3_cat_compare_val' to 'cat_compare_val' to cover all L3/L2 CAT
      features.
      (suggested by Roger Pau)
    - remove parameter 'found' from 'cat_compare_val' and modify the return
      values to let caller know if the id is found or not.
      (suggested by Roger Pau)
    - replace feature list handling to feature array handling.
      (suggested by Roger Pau)
    - replace 'get_cos_num' to 'feat->cos_num'.
      (suggested by Jan Beulich)
    - directly use 'cos_reg_val[0]' as default value.
      (suggested by Jan Beulich)
    - modify patch title to indicate 'L3 CAT'.
      (suggested by Jan Beulich)
    - changes about 'uint64_t' to 'uint32_t'.
      (suggested by Jan Beulich)
v5:
    - modify commit message to provide exact patch name to continue from.
      (suggested by Jan Beulich)
    - remove 'get_cos_max_from_type' because it can be replaced by
      'get_cos_max'.
    - move type check out from callback functions to caller.
      (suggested by Jan Beulich)
    - modify variables names to make them better, e.g. 'feat_tmp' to 'feat'.
      (suggested by Jan Beulich)
    - modify comments according to changes of codes.
      (suggested by Jan Beulich)
v4:
    - create this patch to make codes easier to understand.
      (suggested by Jan Beulich)
---
 xen/arch/x86/psr.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index c912478..a6c6f18 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -720,8 +720,83 @@ static int find_cos(const uint32_t val[], unsigned int array_len,
                     const struct psr_socket_info *info,
                     spinlock_t *ref_lock)
 {
+    unsigned int cos, i;
+    const unsigned int *ref = info->cos_ref;
+    const struct feat_node *feat;
+    unsigned int cos_max;
+
     ASSERT(spin_is_locked(ref_lock));
 
+    /* cos_max is the one of the feature which is being set. */
+    feat = info->features[feat_type];
+    if ( !feat )
+        return -ENOENT;
+
+    cos_max = feat->props->cos_max;
+
+    for ( cos = 0; cos <= cos_max; cos++ )
+    {
+        const uint32_t *val_ptr = val;
+        bool found = false;
+
+        if ( cos && !ref[cos] )
+            continue;
+
+        /*
+         * If fail to find cos in below loop, need find whole feature array
+         * again from beginning.
+         */
+        for ( i = 0; i < PSR_SOCKET_MAX_FEAT; i++ )
+        {
+            uint32_t default_val = 0;
+
+            feat = info->features[i];
+            if ( !feat )
+                continue;
+
+            /*
+             * COS ID 0 always stores the default value so input 0 to get
+             * default value.
+             */
+            feat->props->get_val(feat, 0, &default_val);
+
+            /*
+             * Compare value according to feature array order.
+             * We must follow this order because value array is assembled
+             * as this order.
+             */
+            if ( cos > feat->props->cos_max )
+            {
+                /*
+                 * If cos is bigger than feature's cos_max, the val should be
+                 * default value. Otherwise, it fails to find a COS ID. So we
+                 * have to exit find flow.
+                 */
+                if ( val[0] != default_val )
+                    return -EINVAL;
+
+                found = true;
+            }
+            else
+            {
+                if ( val[0] == feat->cos_reg_val[cos] )
+                    found = true;
+            }
+
+            /* If fail to match, go to next cos to compare. */
+            if ( !found )
+                break;
+
+            val_ptr += feat->props->cos_num;
+            if ( val_ptr - val > array_len )
+                return -ENOSPC;
+        }
+
+        /* For this COS ID all entries in the values array do match. Use it. */
+        if ( found )
+            return cos;
+    }
+
     return -ENOENT;
 }
 
-- 
1.9.1


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