[Xen-devel] [PATCH v9 10/25] x86: refactor psr: L3 CAT: set value: assemble features value array.

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

Only can one COS ID be used by one domain at one time. That means all enabled
features' COS registers at this COS ID are valid for this domain at that time.

When user updates a feature's value, we need make sure all other features'
values are not affected. So, we firstly need gather an array which contains
all features current values and replace the setting feature's value in array
to new value.

Then, we can try to find if there is a COS ID on which all features' COS
registers values are same as the array. If we can find, we just use this COS
ID. If fail to find, we need pick a new COS ID.

This patch implements value array assembling flow.

Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
---
v9:
    - add comments about boundary checking.
      (suggested by Wei Liu)
    - rename 'assemble_val_array' to 'combine_val_array' in pervious patch.
      (suggested by Wei Liu)
    - rename 'l3_cat_get_cos_num' to 'cat_get_cos_num' to cover all L3/L2 CAT
      features.
      (suggested by Roger Pau)
    - rename 'l3_cat_get_old_val' to 'cat_get_old_val' to cover all L3/L2 CAT
      features and reuse cat_get_val in it.
      (suggested by Roger Pau)
    - replace feature list handling to feature array handling.
      (suggested by Roger Pau)
    - modify patch title to indicate 'L3 CAT'.
      (suggested by Jan Beulich)
    - replace 'm' to 'new_val'.
      (suggested by Jan Beulich)
    - move cos check outside callback function.
      (suggested by Jan Beulich)
    - remove 'get_cos_num' callback function.
      (suggested by Jan Beulich)
    - changes about 'uint64_t' to 'uint32_t'.
      (suggested by Jan Beulich)
v6:
    - change 'assemble_val_array' to 'combine_val_array'.
      (suggested by Konrad Rzeszutek Wilk)
    - check return value of 'get_old_val'.
      (suggested by Konrad Rzeszutek Wilk)
    - replace some 'EINVAL' to 'ENOSPC'.
      (suggested by Konrad Rzeszutek Wilk)
v5:
    - modify comments according to changes of codes.
      (suggested by Jan Beulich)
    - change 'bool_t' to 'bool'.
      (suggested by Jan Beulich)
    - modify return value of callback functions because we do not need them
      to return number of entries the feature uses. In caller, we call
      'get_cos_num' to get the number of entries the feature uses.
      (suggested by Jan Beulich)
    - modify variables names to make them better, e.g. 'feat_tmp' to 'feat'.
      (suggested by Jan Beulich)
v4:
    - create this patch to make codes easier to understand.
      (suggested by Jan Beulich)
---
 xen/arch/x86/psr.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 149 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index f8d4be4..18aad8e 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -101,6 +101,28 @@ struct feat_node {
         /* get_val is used to get feature COS register value. */
         void (*get_val)(const struct feat_node *feat, unsigned int cos,
                         enum cbm_type type, uint32_t *val);
+
+        /*
+         * get_old_val and set_new_val are a pair of functions called in order.
+         * The caller will traverse all features in the array and call
+         * 'get_old_val' to get old_cos register value of all supported
+         * features. Then, call 'set_new_val' to set the new value for the
+         * designated feature.
+         *
+         * All the values are set into value array according to the traversal
+         * order, meaning the same order of feature array members.
+         *
+         * The return value meaning of set_new_val:
+         * 0 - success.
+         * negative - error.
+         */
+        void (*get_old_val)(uint32_t val[],
+                            const struct feat_node *feat,
+                            unsigned int old_cos);
+        int (*set_new_val)(uint32_t val[],
+                           const struct feat_node *feat,
+                           enum cbm_type type,
+                           uint32_t new_val);
     } ops;
 
     /* Encapsulate feature specific HW info here. */
@@ -212,6 +234,29 @@ static enum psr_feat_type psr_cbm_type_to_feat_type(enum 
cbm_type type)
 }
 
 /* CAT common functions implementation. */
+static bool psr_check_cbm(unsigned int cbm_len, uint32_t cbm)
+{
+    unsigned int first_bit, zero_bit;
+
+    /* Set bits should only in the range of [0, cbm_len]. */
+    if ( cbm & (~0ul << cbm_len) )
+        return false;
+
+    /* At least one bit need to be set. */
+    if ( cbm == 0 )
+        return false;
+
+    first_bit = find_first_bit((uint64_t *)&cbm, cbm_len);
+    zero_bit = find_next_zero_bit((uint64_t *)&cbm, cbm_len, first_bit);
+
+    /* Set bits should be contiguous. */
+    if ( zero_bit < cbm_len &&
+         find_next_bit((uint64_t *)&cbm, cbm_len, zero_bit) < cbm_len )
+        return false;
+
+    return true;
+}
+
 static void cat_init_feature(struct cpuid_leaf regs,
                              struct feat_node *feat,
                              struct psr_socket_info *info,
@@ -285,11 +330,35 @@ static void cat_get_val(const struct feat_node *feat, 
unsigned int cos,
     *val = feat->cos_reg_val[cos];
 }
 
+/* val[] len checking is done by caller. */
+static void cat_get_old_val(uint32_t val[],
+                            const struct feat_node *feat,
+                            unsigned int old_cos)
+{
+    cat_get_val(feat, old_cos, 0, &val[0]);
+}
+
+/* val[] len checking is done by caller. */
+static int cat_set_new_val(uint32_t val[],
+                           const struct feat_node *feat,
+                           enum cbm_type type,
+                           uint32_t new_val)
+{
+    if ( !psr_check_cbm(feat->info.cat_info.cbm_len, new_val) )
+        return -EINVAL;
+
+    val[0] = new_val;
+
+    return 0;
+}
+
 /* L3 CAT ops */
 static const struct feat_ops l3_cat_ops = {
     .get_cos_max = cat_get_cos_max,
     .get_feat_info = cat_get_feat_info,
     .get_val = cat_get_val,
+    .get_old_val = cat_get_old_val,
+    .set_new_val = cat_set_new_val,
 };
 
 static void __init parse_psr_bool(char *s, char *value, char *feature,
@@ -581,7 +650,21 @@ int psr_get_val(struct domain *d, unsigned int socket,
 /* Set value functions */
 static unsigned int get_cos_num(const struct psr_socket_info *info)
 {
-    return 0;
+    const struct feat_node *feat;
+    unsigned int num = 0, i;
+
+    /* Get all features total amount. */
+    for ( i = 0; i < PSR_SOCKET_MAX_FEAT; i++ )
+    {
+        if ( !info->features[i] )
+            continue;
+
+        feat = info->features[i];
+
+        num += feat->cos_num;
+    }
+
+    return num;
 }
 
 static int gather_val_array(uint32_t val[],
@@ -589,7 +672,34 @@ static int gather_val_array(uint32_t val[],
                             const struct psr_socket_info *info,
                             unsigned int old_cos)
 {
-    return -EINVAL;
+    const struct feat_node *feat;
+    unsigned int i;
+
+    if ( !val )
+        return -EINVAL;
+
+    /* Get all features current values according to old_cos. */
+    for ( i = 0; i < PSR_SOCKET_MAX_FEAT; i++ )
+    {
+        if ( !info->features[i] )
+            continue;
+
+        feat = info->features[i];
+
+        if ( old_cos > feat->ops.get_cos_max(feat) )
+            old_cos = 0;
+
+        /* value getting order is same as feature array */
+        feat->ops.get_old_val(val, feat, old_cos);
+
+        array_len -= feat->cos_num;
+        if ( array_len < 0 )
+            return -ENOSPC;
+
+        val += feat->cos_num;
+    }
+
+    return 0;
 }
 
 static int insert_new_val_to_array(uint32_t val[],
@@ -599,7 +709,43 @@ static int insert_new_val_to_array(uint32_t val[],
                                    enum cbm_type type,
                                    uint32_t new_val)
 {
-    return -EINVAL;
+    const struct feat_node *feat;
+    int ret;
+    unsigned int i;
+
+    ASSERT(feat_type < PSR_SOCKET_MAX_FEAT);
+
+    /* Set new value into array according to feature's position in array. */
+    for ( i = 0; i < feat_type; i++ )
+    {
+        if ( !info->features[i] )
+            continue;
+
+        feat = info->features[i];
+
+        array_len -= feat->cos_num;
+        if ( array_len <= 0 )
+            return -ENOSPC;
+
+        val += feat->cos_num;
+    }
+
+    feat = info->features[feat_type];
+
+    array_len -= feat->cos_num;
+    if ( array_len < 0 )
+        return -ENOSPC;
+
+    /*
+     * Value setting position is same as feature array.
+     * Different features may have different setting behaviors, e.g. CDP
+     * has two values (DATA/CODE) which need us to save input value to
+     * different position in the array according to type, so we have to
+     * maintain a callback function.
+     */
+    ret = feat->ops.set_new_val(val, feat, type, new_val);
+
+    return ret;
 }
 
 static int find_cos(const uint32_t val[], uint32_t array_len,
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel