[Xen-devel] [PATCH v10 13/25] 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 MSR of the
designated feature.

Till now, set value process is completed.

Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
---
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 | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index 44c9313..0f57676 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -101,6 +101,10 @@ struct feat_node {
         /* get_val is used to get feature COS register value. */
         void (*get_val)(const struct feat_node *feat, unsigned int cos,
                         uint32_t *val);
+
+        /* write_msr is used to write out feature MSR register. */
+        void (*write_msr)(unsigned int cos, uint32_t val,
+                          struct feat_node *feat);
     } *props;
 
     uint32_t cos_reg_val[MAX_COS_REG_CNT];
@@ -315,10 +319,21 @@ static void cat_get_val(const struct feat_node *feat, 
unsigned int cos,
 }
 
 /* L3 CAT ops */
+static void l3_cat_write_msr(unsigned int cos, uint32_t val,
+                             struct feat_node *feat)
+{
+    if ( feat->cos_reg_val[cos] != val )
+    {
+        feat->cos_reg_val[cos] = val;
+        wrmsrl(MSR_IA32_PSR_L3_MASK(cos), val);
+    }
+}
+
 static struct feat_props l3_cat_props = {
     .cos_num = 1,
     .get_feat_info = cat_get_feat_info,
     .get_val = cat_get_val,
+    .write_msr = l3_cat_write_msr,
 };
 
 static void __init parse_psr_bool(char *s, char *value, char *feature,
@@ -878,10 +893,56 @@ 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;
+    uint32_t val;
+};
+
+static void do_write_psr_msr(void *data)
+{
+    struct cos_write_info *info = data;
+    unsigned int cos            = info->cos;
+    struct feat_node *feat      = info->feature;
+
+    if ( cos > feat->props->cos_max )
+        return;
+
+    feat->props->write_msr(cos, info->val, feat);
+}
+
 static int write_psr_msr(unsigned int socket, unsigned int cos,
                          uint32_t val, enum psr_feat_type feat_type)
 {
-    return -ENOENT;
+    struct psr_socket_info *info = get_socket_info(socket);
+    struct cos_write_info data =
+    {
+        .cos = cos,
+        .feature = info->features[feat_type],
+        .val = val,
+    };
+
+    if ( socket == cpu_to_socket(smp_processor_id()) )
+        do_write_psr_msr(&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_msr, &data, 1);
+    }
+
+    return 0;
 }
 
 /* The whole set process is protected by domctl_lock. */
-- 
1.9.1


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