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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v8 02/13] x86: detect and initialize Intel CAT feature
Detect Intel Cache Allocation Technology(CAT) feature and store the
cpuid information for later use. Currently only L3 cache allocation is
supported. The L3 CAT features may vary among sockets so per-socket
feature information is stored. The initialization can happen either at
boot time or when CPU(s) is hot plugged after booting.
Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Changes in v8:
* Remove cat_socket_init_bitmap and rename cat_socket_enable_bitmap.
* Ensure opt_cos_max is not too small.
* Use CPU_DEAD instead of CPU_DYING.
* indentation fix.
Changes in v7:
* Clear the init/enable flag when a socket going offline.
* Reorder the statements in init_psr_cat.
Changes in v6:
* Introduce cat_socket_init(_enable)_bitmap.
Changes in v5:
* Add cos_max boot option.
Changes in v4:
* check X86_FEATURE_CAT available before doing initialization.
Changes in v3:
* Remove num_sockets boot option instead calculate it at boot time.
* Name hardcoded CAT cpuid leaf as PSR_CPUID_LEVEL_CAT.
Changes in v2:
* socket_num => num_sockets and fix several documentaion issues.
* refactor boot line parameters parsing into standlone patch.
* set opt_num_sockets = NR_CPUS when opt_num_sockets > NR_CPUS.
* replace CPU_ONLINE with CPU_STARTING and integrate that into scheduling
improvement patch.
* reimplement get_max_socket() with cpu_to_socket();
* cbm is still uint64 as there is a path forward for supporting long masks.
---
docs/misc/xen-command-line.markdown | 15 ++++++-
xen/arch/x86/psr.c | 90 ++++++++++++++++++++++++++++++++++++-
xen/include/asm-x86/cpufeature.h | 1 +
xen/include/asm-x86/psr.h | 3 ++
4 files changed, 106 insertions(+), 3 deletions(-)
diff --git a/docs/misc/xen-command-line.markdown
b/docs/misc/xen-command-line.markdown
index 4889e27..28a09a8 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1137,9 +1137,9 @@ This option can be specified more than once (up to 8
times at present).
> `= <integer>`
### psr (Intel)
-> `= List of ( cmt:<boolean> | rmid_max:<integer> )`
+> `= List of ( cmt:<boolean> | rmid_max:<integer> | cat:<boolean> |
cos_max:<integer> )`
-> Default: `psr=cmt:0,rmid_max:255`
+> Default: `psr=cmt:0,rmid_max:255,cat:0,cos_max:255`
Platform Shared Resource(PSR) Services. Intel Haswell and later server
platforms offer information about the sharing of resources.
@@ -1149,6 +1149,12 @@ Monitoring ID(RMID) is used to bind the domain to
corresponding shared
resource. RMID is a hardware-provided layer of abstraction between software
and logical processors.
+To use the PSR cache allocation service for a certain domain, a capacity
+bitmasks(CBM) is used to bind the domain to corresponding shared resource.
+CBM represents cache capacity and indicates the degree of overlap and isolation
+between domains. In hypervisor a Class of Service(COS) ID is allocated for each
+unique CBM.
+
The following resources are available:
* Cache Monitoring Technology (Haswell and later). Information regarding the
@@ -1159,6 +1165,11 @@ The following resources are available:
total/local memory bandwidth. Follow the same options with Cache Monitoring
Technology.
+* Cache Alllocation Technology (Broadwell and later). Information regarding
+ the cache allocation.
+ * `cat` instructs Xen to enable/disable Cache Allocation Technology.
+ * `cos_max` indicates the max value for COS ID.
+
### reboot
> `= t[riple] | k[bd] | a[cpi] | p[ci] | P[ower] | e[fi] | n[o] [, [w]arm |
> [c]old]`
diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
index 2490d22..471296e 100644
--- a/xen/arch/x86/psr.c
+++ b/xen/arch/x86/psr.c
@@ -19,14 +19,25 @@
#include <asm/psr.h>
#define PSR_CMT (1<<0)
+#define PSR_CAT (1<<1)
+
+struct psr_cat_socket_info {
+ unsigned int cbm_len;
+ unsigned int cos_max;
+};
struct psr_assoc {
uint64_t val;
};
struct psr_cmt *__read_mostly psr_cmt;
+
+static unsigned long *__read_mostly cat_socket_enable;
+static struct psr_cat_socket_info *__read_mostly cat_socket_info;
+
static unsigned int __initdata opt_psr;
static unsigned int __initdata opt_rmid_max = 255;
+static unsigned int opt_cos_max = 255;
static uint64_t rmid_mask;
static DEFINE_PER_CPU(struct psr_assoc, psr_assoc);
@@ -63,10 +74,14 @@ static void __init parse_psr_param(char *s)
*val_str++ = '\0';
parse_psr_bool(s, val_str, "cmt", PSR_CMT);
+ parse_psr_bool(s, val_str, "cat", PSR_CAT);
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 );
}
@@ -194,16 +209,86 @@ void psr_ctxt_switch_to(struct domain *d)
}
}
+static void cat_cpu_init(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ struct psr_cat_socket_info *info;
+ unsigned int socket;
+ unsigned int cpu = smp_processor_id();
+ const struct cpuinfo_x86 *c = cpu_data + cpu;
+
+ if ( !cpu_has(c, X86_FEATURE_CAT) )
+ return;
+
+ socket = cpu_to_socket(cpu);
+ if ( test_bit(socket, cat_socket_enable) )
+ return;
+
+ cpuid_count(PSR_CPUID_LEVEL_CAT, 0, &eax, &ebx, &ecx, &edx);
+ if ( ebx & PSR_RESOURCE_TYPE_L3 )
+ {
+ cpuid_count(PSR_CPUID_LEVEL_CAT, 1, &eax, &ebx, &ecx, &edx);
+ info = cat_socket_info + socket;
+ info->cbm_len = (eax & 0x1f) + 1;
+ info->cos_max = min(opt_cos_max, edx & 0xffff);
+
+ set_bit(socket, cat_socket_enable);
+ printk(XENLOG_INFO "CAT: enabled on socket %u, cos_max:%u,
cbm_len:%u\n",
+ socket, info->cos_max, info->cbm_len);
+ }
+}
+
+static void cat_cpu_fini(unsigned int cpu)
+{
+ unsigned int socket = cpu_to_socket(cpu);
+
+ if ( !socket_cpumask[socket] || cpumask_empty(socket_cpumask[socket]) )
+ clear_bit(socket, cat_socket_enable);
+}
+
+static void __init init_psr_cat(void)
+{
+ if ( opt_cos_max < 1 )
+ {
+ printk(XENLOG_INFO "CAT: disabled, cos_max is too small\n");
+ return;
+ }
+
+ cat_socket_enable = xzalloc_array(unsigned long,
BITS_TO_LONGS(nr_sockets));
+ cat_socket_info = xzalloc_array(struct psr_cat_socket_info, nr_sockets);
+
+ if ( !cat_socket_enable || !cat_socket_info )
+ {
+ xfree(cat_socket_enable);
+ cat_socket_enable = NULL;
+ xfree(cat_socket_info);
+ cat_socket_info = NULL;
+ }
+}
+
static void psr_cpu_init(void)
{
+ if ( cat_socket_info )
+ cat_cpu_init();
+
psr_assoc_init();
}
+static void psr_cpu_fini(unsigned int cpu)
+{
+ if ( cat_socket_info )
+ cat_cpu_fini(cpu);
+}
+
static int cpu_callback(
struct notifier_block *nfb, unsigned long action, void *hcpu)
{
+ unsigned int cpu = (unsigned long)hcpu;
+
if ( action == CPU_STARTING )
psr_cpu_init();
+ else if ( action == CPU_DEAD )
+ psr_cpu_fini(cpu);
return NOTIFY_DONE;
}
@@ -217,8 +302,11 @@ static int __init psr_presmp_init(void)
if ( (opt_psr & PSR_CMT) && opt_rmid_max )
init_psr_cmt(opt_rmid_max);
+ if ( opt_psr & PSR_CAT )
+ init_psr_cat();
+
psr_cpu_init();
- if ( psr_cmt_enabled() )
+ if ( psr_cmt_enabled() || cat_socket_info )
register_cpu_notifier(&cpu_nfb);
return 0;
diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h
index 7963a3a..8c0f0a6 100644
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -149,6 +149,7 @@
#define X86_FEATURE_CMT (7*32+12) /* Cache Monitoring Technology */
#define X86_FEATURE_NO_FPU_SEL (7*32+13) /* FPU CS/DS stored as zero */
#define X86_FEATURE_MPX (7*32+14) /* Memory Protection
Extensions */
+#define X86_FEATURE_CAT (7*32+15) /* Cache Allocation Technology */
#define X86_FEATURE_RDSEED (7*32+18) /* RDSEED instruction */
#define X86_FEATURE_ADX (7*32+19) /* ADCX, ADOX instructions */
#define X86_FEATURE_SMAP (7*32+20) /* Supervisor Mode Access Prevention
*/
diff --git a/xen/include/asm-x86/psr.h b/xen/include/asm-x86/psr.h
index 12d593b..bdda111 100644
--- a/xen/include/asm-x86/psr.h
+++ b/xen/include/asm-x86/psr.h
@@ -18,6 +18,9 @@
#include <xen/types.h>
+/* CAT cpuid level */
+#define PSR_CPUID_LEVEL_CAT 0x10
+
/* Resource Type Enumeration */
#define PSR_RESOURCE_TYPE_L3 0x2
--
1.9.1
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