[Xen-devel] [PATCH v15 12/23] x86: refactor psr: L3 CAT: set value: implement write msr flow.

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

Continue from previous patch:
'x86: refactor psr: L3 CAT: set value: implement cos id picking flow.'

We have got the feature value and COS ID to set. Then, we write MSRs of the
designated feature.

Till now, set value process is completed.

Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v15:
    - remove unnecessary 'else' in 'write_psr_msrs'.
      (suggested by Jan Beulich)
v14:
    - changes related to 'skip_prior_features' change in previous patch.
      (suggested by Jan Beulich)
v13:
    - use 'skip_prior_features'.
      (suggested by Jan Beulich)
    - add 'const' for some variables.
      (suggested by Jan Beulich)
v12:
    - declare same type varaibles in one line.
      (suggested by Jan Beulich)
    - replace 'feat_type' to 'props' in 'struct cos_write_info'.
      (suggested by Jan Beulich)
    - assign the 'cos_num' to a local variable.
      (suggested by Jan Beulich)
    - use 'ASSERT_UNREACHABLE()' to record bug and return error code if feat
      exists but props does not exist.
      (suggested by Jan Beulich)
v11:
    - rename 'write_psr_msr' to 'write_psr_msrs'.
    - rename 'do_write_psr_msr' to 'do_write_psr_msrs'.
    - change parameters and codes of 'write_psr_msrs' to handle value array.
    - add 'feat_type' in 'struct cos_write_info' to handle props array.
    - in 'do_write_psr_msrs', write value array into msrs according to
      'props->type[i]'.
    - move 'feat->cos_reg_val' assignment and value comparison in 'write_msr'
      callback function out as generic codes.
      (suggested by Jan Beulich)
    - move check from 'do_write_psr_msrs' to 'write_psr_msrs'.
      (suggested by Jan Beulich)
    - change about 'cos_max'.
      (suggested by Jan Beulich)
    - change about 'feat_props'.
      (suggested by Jan Beulich)
v10:
    - remove 'type' from 'write_msr' parameter list. Will add it back when
      implementing CDP.
      (suggested by Jan Beulich)
    - remove unnecessary casts.
      (suggested by Jan Beulich)
    - changes about 'props'.
      (suggested by Jan Beulich)
v9:
    - replace feature list handling to feature array handling.
      (suggested by Roger Pau)
    - add 'array_len' in 'struct cos_write_info' and check if val array
      exceeds it.
    - modify 'write_psr_msr' flow only to set one value a time. No need to
      set whole feature array values.
    - modify patch title to indicate 'L3 CAT'.
      (suggested by Jan Beulich)
    - changes about 'uint64_t' to 'uint32_t'.
      (suggested by Jan Beulich)
v8:
    - modify 'write_msr' callback function to 'void' because we have to set
      all features' cbm. When input cos exceeds some features' cos_max, just
      skip them but not break the iteration.
v5:
    - modify commit message to provide exact patch name to continue from.
      (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)
    - 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)
    - correct code format.
      (suggested by Jan Beulich)
v4:
    - create this patch to make codes easier understand.
      (suggested by Jan Beulich)
---
 xen/arch/x86/psr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index b553112..6ea2e4e 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -113,6 +113,9 @@ static const struct feat_props {
     /* get_feat_info is used to return feature HW info through sysctl. */
     bool (*get_feat_info)(const struct feat_node *feat,
                           uint32_t data[], unsigned int array_len);
+
+    /* write_msr is used to write out feature MSR register. */
+    void (*write_msr)(unsigned int cos, uint32_t val, enum cbm_type type);
 } *feat_props[FEAT_TYPE_NUM];
 
 /*
@@ -289,11 +292,17 @@ static bool cat_get_feat_info(const struct feat_node 
*feat,
 }
 
 /* L3 CAT props */
+static void l3_cat_write_msr(unsigned int cos, uint32_t val, enum cbm_type 
type)
+{
+    wrmsrl(MSR_IA32_PSR_L3_MASK(cos), val);
+}
+
 static const struct feat_props l3_cat_props = {
     .cos_num = 1,
     .type[0] = PSR_CBM_TYPE_L3,
     .alt_type = PSR_CBM_TYPE_UNKNOWN,
     .get_feat_info = cat_get_feat_info,
+    .write_msr = l3_cat_write_msr,
 };
 
 static void __init parse_psr_bool(char *s, char *value, char *feature,
@@ -947,11 +956,79 @@ static int pick_avail_cos(const struct psr_socket_info 
*info,
     return -EOVERFLOW;
 }
 
+static unsigned int get_socket_cpu(unsigned int socket)
+{
+    if ( likely(socket < nr_sockets) )
+        return cpumask_any(socket_cpumask[socket]);
+
+    return nr_cpu_ids;
+}
+
+struct cos_write_info
+{
+    unsigned int cos;
+    struct feat_node *feature;
+    const uint32_t *val;
+    const struct feat_props *props;
+};
+
+static void do_write_psr_msrs(void *data)
+{
+    const struct cos_write_info *info = data;
+    struct feat_node *feat = info->feature;
+    const struct feat_props *props = info->props;
+    unsigned int i, cos = info->cos, cos_num = props->cos_num;
+
+    for ( i = 0; i < cos_num; i++ )
+    {
+        if ( feat->cos_reg_val[cos * cos_num + i] != info->val[i] )
+        {
+            feat->cos_reg_val[cos * cos_num + i] = info->val[i];
+            props->write_msr(cos, info->val[i], props->type[i]);
+        }
+    }
+}
+
 static int write_psr_msrs(unsigned int socket, unsigned int cos,
                           const uint32_t val[], unsigned int array_len,
                           enum psr_feat_type feat_type)
 {
-    return -ENOENT;
+    int ret;
+    struct psr_socket_info *info = get_socket_info(socket);
+    struct cos_write_info data =
+    {
+        .cos = cos,
+        .feature = info->features[feat_type],
+        .props = feat_props[feat_type],
+    };
+
+    if ( cos > info->features[feat_type]->cos_max )
+        return -EINVAL;
+
+    /* Skip to the feature's value head. */
+    ret = skip_prior_features(&array_len, feat_type);
+    if ( ret < 0 )
+        return ret;
+
+    val += ret;
+
+    if ( array_len < feat_props[feat_type]->cos_num )
+        return -ENOSPC;
+
+    data.val = val;
+
+    if ( socket == cpu_to_socket(smp_processor_id()) )
+        do_write_psr_msrs(&data);
+    else
+    {
+        unsigned int cpu = get_socket_cpu(socket);
+
+        if ( cpu >= nr_cpu_ids )
+            return -ENOTSOCK;
+        on_selected_cpus(cpumask_of(cpu), do_write_psr_msrs, &data, 1);
+    }
+
+    return 0;
 }
 
 int psr_set_val(struct domain *d, unsigned int socket,
-- 
1.9.1


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