[Xen-devel] [PATCH v9 05/25] x86: refactor psr: L3 CAT: implement CPU init and free flow.

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

This patch implements the CPU init and free flow including L3 CAT
initialization and feature array free. It includes below flows:
1. presmp init:
    - parse command line parameter.
    - allocate socket info for every socket.
    - allocate feature resource.
    - initialize socket info, get feature info and add feature into feature
      array per cpuid result.
    - free resources allocated if error happens.
    - register cpu notifier to handle cpu events.
2. cpu notifier:
    - handle cpu online events, if initialization work has been done before,
      do nothing.
    - handle cpu offline events, if it is the last cpu offline, free feature
      resources.

Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
---
v9:
    - add commit message to explain the flows.
    - handle cpu offline and online again case to read MSRs registers values
      back and save them into cos array to make user can get real data.
    - create a new patch about moving 'cpuid_count_leaf'.
      (suggested by Wei Liu)
    - modify comment to explain why not free some resource in 'free_feature'.
      (suggested by Wei Liu)
    - implement 'psr_alloc_feat_enabled' to check if allocation feature is
      enabled in cmdline and some initialization work done.
      (suggested by Wei Liu)
    - implement 'cat_default_val' to set default value for CAT features.
      (suggested by Wei Liu)
    - replace feature list handling to feature array handling.
      (suggested by Roger Pau)
    - implement a common 'cat_init_feature' to replace L3 CAT/L2 CAT specific
      init functions.
      (suggested by Roger Pau)
    - modify comments for global feature node.
      (suggested by Jan Beulich)
    - remove unnecessary comments.
      (suggested by Jan Beulich)
    - remove unnecessary 'else'.
      (suggested by Jan Beulich)
    - remove 'nr_feat'.
      (suggested by Jan Beulich)
    - modify patch title to indicate 'L3 CAT'.
      (suggested by Jan Beulich)
    - check global flag with boot cpu operations.
      (suggested by Jan Beulich)
    - remove 'cpu_init_work' and move codes into 'psr_cpu_init'.
      (suggested by Jan Beulich)
    - remove 'cpu_fini_work' and move codes into 'psr_cpu_fini'.
      (suggested by Jan Beulich)
    - assign value for 'cos_num'.
      (suggested by Jan Beulich)
    - change about 'uint64_t' to 'uint32_t'.
      (suggested by Jan Beulich)
v8:
    - fix format issue.
      (suggested by Konrad Rzeszutek Wilk)
    - add comments to explain why we care about cpumask_empty when the last
      cpu on socket is offline.
      (suggested by Konrad Rzeszutek Wilk)
v7:
    - initialize structure objects for avoiding surprise.
      (suggested by Konrad Rzeszutek Wilk)
    - fix typo.
      (suggested by Konrad Rzeszutek Wilk)
    - fix a logical mistake when handling the last cpu offline event.
      (suggested by Konrad Rzeszutek Wilk)
v6:
    - use 'struct cpuid_leaf' introduced in Andrew's patch.
      (suggested by Konrad Rzeszutek Wilk)
    - add comments about cpu_add_remove_lock.
      (suggested by Konrad Rzeszutek Wilk)
    - change 'clear_bit' to '__clear_bit'.
      (suggested by Konrad Rzeszutek Wilk)
    - add 'ASSERT' check when setting 'feat_mask'.
      (suggested by Konrad Rzeszutek Wilk)
    - adjust 'printk' position to avoid odd spacing.
      (suggested by Konrad Rzeszutek Wilk)
    - add comment to explain usage of 'feat_l3_cat'.
      (suggested by Konrad Rzeszutek Wilk)
    - fix wording.
      (suggested by Konrad Rzeszutek Wilk)
    - move 'cpuid_count_leaf' helper function to 'asm-x86/processor.h'.
      It cannot be moved to 'cpuid.h' which causes compilation error because
      of header file loop reference.
      (suggested by Andrew Cooper)
v5:
    - add comment to explain the reason to define 'feat_l3_cat'.
      (suggested by Jan Beulich)
    - use 'list_for_each_entry_safe'.
      (suggested by Jan Beulich)
    - remove codes to free 'feat_l3_cat' in 'free_feature' to avoid the need
      for an allocation the next time a CPU comes online.
      (suggested by Jan Beulich)
    - define 'struct cpuid_leaf_regs' to encapsulate eax~edx.
      (suggested by Jan Beulich)
    - print feature info on a socket only when 'opt_cpu_info' is true.
      (suggested by Jan Beulich)
    - declare global variable 'l3_cat_ops' to 'static const'.
      (suggested by Jan Beulich)
    - use 'current_cpu_data'.
      (suggested by Jan Beulich)
    - rename 'feat_tmp' to 'feat'.
      (suggested by Jan Beulich)
    - clear PQE feature bit when the maximum CPUID level is too low.
      (suggested by Jan Beulich)
    - directly call 'l3_cat_init_feature'. No need to make it a callback
      function.
      (suggested by Jan Beulich)
    - remove local variable 'info'.
      (suggested by Jan Beulich)
    - move 'INIT_LIST_HEAD' into 'cpu_init_work' to be together with
      spin_lock_init().
      (suggested by Jan Beulich)
    - remove 'cpu_prepare_work' and move its content into 'psr_cpu_prepare'.
      (suggested by Jan Beulich)
v4:
    - create this patch because of removing all CAT/CDP old codes to make
      implementation be more easily understood.
      (suggested by Jan Beulich)
---
 xen/arch/x86/psr.c | 202 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 197 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index 822f1c0..66a9ce8 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -18,6 +18,7 @@
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <asm/psr.h>
+#include <asm/x86_emulate.h>
 
 /*
  * Terminology:
@@ -34,6 +35,9 @@
 #define PSR_CAT        (1<<1)
 #define PSR_CDP        (1<<2)
 
+#define CAT_CBM_LEN_MASK 0x1f
+#define CAT_COS_MAX_MASK 0xffff
+
 /*
  * Per SDM chapter 'Cache Allocation Technology: Cache Mask Configuration',
  * the MSRs ranging from 0C90H through 0D0FH (inclusive), enables support for
@@ -46,6 +50,9 @@
  */
 #define MAX_COS_REG_CNT  128
 
+/* CAT features use 1 COS register in one access. */
+#define CAT_COS_NUM      1
+
 enum psr_feat_type {
     PSR_SOCKET_L3_CAT = 0,
     PSR_SOCKET_L3_CDP,
@@ -126,11 +133,110 @@ struct psr_assoc {
 
 struct psr_cmt *__read_mostly psr_cmt;
 
+static struct psr_socket_info *__read_mostly socket_info;
+
 static unsigned int opt_psr;
 static unsigned int __initdata opt_rmid_max = 255;
+static unsigned int __read_mostly opt_cos_max = MAX_COS_REG_CNT;
 static uint64_t rmid_mask;
 static DEFINE_PER_CPU(struct psr_assoc, psr_assoc);
 
+/*
+ * Declare global feature node for every feature to facilitate the feature
+ * array creation. It is used to transiently store a spare node.
+ */
+static struct feat_node *feat_l3_cat;
+
+/* Common functions */
+#define cat_default_val(len)                 \
+            ( (uint32_t)((1ul << len) - 1) )
+
+/*
+ * Use this function to check if any allocation feature has been enabled
+ * in cmdline.
+ */
+static bool psr_alloc_feat_enabled(void)
+{
+    return ((!socket_info) ? false : true );
+}
+
+static void free_feature(struct psr_socket_info *info)
+{
+    unsigned int i;
+
+    if ( !info )
+        return;
+
+    /*
+     * Free resources of features. The global feature object, e.g. feat_l3_cat,
+     * may not be freed here if it is not added into array. It is simply being
+     * kept until the next CPU online attempt.
+     */
+    for ( i = 0; i < PSR_SOCKET_MAX_FEAT; i++ )
+    {
+        if ( !info->features[i] )
+            continue;
+
+        xfree(info->features[i]);
+        info->features[i] = NULL;
+        __clear_bit(i, &info->feat_mask);
+    }
+}
+
+/* CAT common functions implementation. */
+static void cat_init_feature(struct cpuid_leaf regs,
+                             struct feat_node *feat,
+                             struct psr_socket_info *info,
+                             enum psr_feat_type type)
+{
+    unsigned int socket, i;
+    struct psr_cat_hw_info cat = { };
+    uint64_t val;
+
+    /* No valid value so do not enable feature. */
+    if ( !regs.a || !regs.d )
+        return;
+
+    cat.cbm_len = (regs.a & CAT_CBM_LEN_MASK) + 1;
+    cat.cos_max = min(opt_cos_max, regs.d & CAT_COS_MAX_MASK);
+
+    /* cos=0 is reserved as default cbm(all bits within cbm_len are 1). */
+    feat->cos_reg_val[0] = cat_default_val(cat.cbm_len);
+    /*
+     * To handle cpu offline and then online case, we need read MSRs back to
+     * save values into cos_reg_val array.
+     */
+    for ( i = 1; i <= cat.cos_max; i++ )
+    {
+        rdmsrl(MSR_IA32_PSR_L3_MASK(i), val);
+        feat->cos_reg_val[i] = (uint32_t)val;
+    }
+
+    feat->info.cat_info = cat;
+    feat->cos_num = CAT_COS_NUM;
+
+    /* Add this feature into array. */
+    info->features[type] = feat;
+
+    ASSERT(!test_bit(type, &info->feat_mask));
+    __set_bit(type, &info->feat_mask);
+
+    socket = cpu_to_socket(smp_processor_id());
+    if ( !opt_cpu_info )
+        return;
+
+    printk(XENLOG_INFO "%s CAT: enabled on socket %u, cos_max:%u, 
cbm_len:%u\n",
+           ((type == PSR_SOCKET_L3_CAT) ? "L3" : "L2"),
+           socket, feat->info.cat_info.cos_max,
+           feat->info.cat_info.cbm_len);
+
+    return;
+}
+
+/* L3 CAT ops */
+static const struct feat_ops l3_cat_ops = {
+};
+
 static void __init parse_psr_bool(char *s, char *value, char *feature,
                                   unsigned int mask)
 {
@@ -170,6 +276,9 @@ static void __init parse_psr_param(char *s)
         if ( val_str && !strcmp(s, "rmid_max") )
             opt_rmid_max = simple_strtoul(val_str, NULL, 0);
 
+        if ( val_str && !strcmp(s, "cos_max") )
+            opt_cos_max = simple_strtoul(val_str, NULL, 0);
+
         s = ss + 1;
     } while ( ss );
 }
@@ -325,19 +434,98 @@ void psr_domain_free(struct domain *d)
     psr_free_rmid(d);
 }
 
-static int psr_cpu_prepare(unsigned int cpu)
+static void __init init_psr(void)
 {
+    if ( opt_cos_max < 1 )
+    {
+        printk(XENLOG_INFO "CAT: disabled, cos_max is too small\n");
+        return;
+    }
+
+    socket_info = xzalloc_array(struct psr_socket_info, nr_sockets);
+
+    if ( !socket_info )
+    {
+        printk(XENLOG_INFO "Failed to alloc socket_info!\n");
+        return;
+    }
+}
+
+static void __init psr_free(void)
+{
+    xfree(socket_info);
+    socket_info = NULL;
+}
+
+static int psr_cpu_prepare(void)
+{
+    if ( !psr_alloc_feat_enabled() )
+        return 0;
+
+    /* Malloc memory for the global feature head here. */
+    if ( feat_l3_cat == NULL &&
+         (feat_l3_cat = xzalloc(struct feat_node)) == NULL )
+        return -ENOMEM;
+
     return 0;
 }
 
 static void psr_cpu_init(void)
 {
+    struct psr_socket_info *info;
+    unsigned int socket, i;
+    unsigned int cpu = smp_processor_id();
+    struct feat_node *feat;
+    struct cpuid_leaf regs;
+
+    if ( !psr_alloc_feat_enabled() || !boot_cpu_has(X86_FEATURE_PQE) )
+        goto assoc_init;
+
+    if ( boot_cpu_data.cpuid_level < PSR_CPUID_LEVEL_CAT )
+    {
+        setup_clear_cpu_cap(X86_FEATURE_PQE);
+        goto assoc_init;
+    }
+
+    socket = cpu_to_socket(cpu);
+    info = socket_info + socket;
+    if ( info->feat_mask )
+        goto assoc_init;
+
+    for ( i = 0; i < PSR_SOCKET_MAX_FEAT; i++ )
+        info->features[i] = NULL;
+
+    spin_lock_init(&info->ref_lock);
+
+    cpuid_count_leaf(PSR_CPUID_LEVEL_CAT, 0, &regs);
+    if ( regs.b & PSR_RESOURCE_TYPE_L3 )
+    {
+        cpuid_count_leaf(PSR_CPUID_LEVEL_CAT, 1, &regs);
+
+        feat = feat_l3_cat;
+        feat_l3_cat = NULL;
+        feat->ops = l3_cat_ops;
+
+        cat_init_feature(regs, feat, info, PSR_SOCKET_L3_CAT);
+    }
+
+assoc_init:
     psr_assoc_init();
 }
 
 static void psr_cpu_fini(unsigned int cpu)
 {
-    return;
+    unsigned int socket = cpu_to_socket(cpu);
+
+    if ( !psr_alloc_feat_enabled() )
+        return;
+
+    /*
+     * We only free when we are the last CPU in the socket. The socket_cpumask
+     * is cleared prior to this notification code by remove_siblinginfo().
+     */
+    if ( socket_cpumask[socket] && cpumask_empty(socket_cpumask[socket]) )
+        free_feature(socket_info + socket);
 }
 
 static int cpu_callback(
@@ -349,7 +537,7 @@ static int cpu_callback(
     switch ( action )
     {
     case CPU_UP_PREPARE:
-        rc = psr_cpu_prepare(cpu);
+        rc = psr_cpu_prepare();
         break;
     case CPU_STARTING:
         psr_cpu_init();
@@ -378,10 +566,14 @@ static int __init psr_presmp_init(void)
     if ( (opt_psr & PSR_CMT) && opt_rmid_max )
         init_psr_cmt(opt_rmid_max);
 
-    psr_cpu_prepare(0);
+    if ( opt_psr & PSR_CAT )
+        init_psr();
+
+    if ( psr_cpu_prepare() )
+        psr_free();
 
     psr_cpu_init();
-    if ( psr_cmt_enabled() )
+    if ( psr_cmt_enabled() || psr_alloc_feat_enabled() )
         register_cpu_notifier(&cpu_nfb);
 
     return 0;
-- 
1.9.1


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