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xen/PMU: Sysfs interface for setting Xen PMU mode

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Set Xen's PMU mode via /sys/hypervisor/pmu/pmu_mode. Add XENPMU hypercall.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Boris Ostrovsky 2015-08-10 16:34:33 -04:00 committed by David Vrabel
parent a11f4f0a4e
commit 5f14154882
7 changed files with 228 additions and 1 deletions
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23
Documentation/ABI/testing/sysfs-hypervisor-pmu Normal file
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@ -0,0 +1,23 @@
What: /sys/hypervisor/pmu/pmu_mode
Date: August 2015
KernelVersion: 4.3
Contact: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Description:
Describes mode that Xen's performance-monitoring unit (PMU)
uses. Accepted values are
"off" -- PMU is disabled
"self" -- The guest can profile itself
"hv" -- The guest can profile itself and, if it is
privileged (e.g. dom0), the hypervisor
"all" -- The guest can profile itself, the hypervisor
and all other guests. Only available to
privileged guests.
What: /sys/hypervisor/pmu/pmu_features
Date: August 2015
KernelVersion: 4.3
Contact: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Description:
Describes Xen PMU features (as an integer). A set bit indicates
that the corresponding feature is enabled. See
include/xen/interface/xenpmu.h for available features

6
arch/x86/include/asm/xen/hypercall.h
View File

@ -465,6 +465,12 @@ HYPERVISOR_tmem_op(
return _hypercall1(int, tmem_op, op);
}
static inline int
HYPERVISOR_xenpmu_op(unsigned int op, void *arg)
{
return _hypercall2(int, xenpmu_op, op, arg);
}
static inline void
MULTI_fpu_taskswitch(struct multicall_entry *mcl, int set)
{

1
arch/x86/xen/Kconfig
View File

@ -7,6 +7,7 @@ config XEN
depends on PARAVIRT
select PARAVIRT_CLOCK
select XEN_HAVE_PVMMU
select XEN_HAVE_VPMU
depends on X86_64 || (X86_32 && X86_PAE)
depends on X86_TSC
help

3
drivers/xen/Kconfig
View File

@ -288,4 +288,7 @@ config XEN_SYMS
Exports hypervisor symbols (along with their types and addresses) via
/proc/xen/xensyms file, similar to /proc/kallsyms
config XEN_HAVE_VPMU
bool
endmenu

136
drivers/xen/sys-hypervisor.c
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@ -20,6 +20,9 @@
#include <xen/xenbus.h>
#include <xen/interface/xen.h>
#include <xen/interface/version.h>
#ifdef CONFIG_XEN_HAVE_VPMU
#include <xen/interface/xenpmu.h>
#endif
#define HYPERVISOR_ATTR_RO(_name) \
static struct hyp_sysfs_attr _name##_attr = __ATTR_RO(_name)
@ -368,6 +371,126 @@ static void xen_properties_destroy(void)
sysfs_remove_group(hypervisor_kobj, &xen_properties_group);
}
#ifdef CONFIG_XEN_HAVE_VPMU
struct pmu_mode {
const char *name;
uint32_t mode;
};
static struct pmu_mode pmu_modes[] = {
{"off", XENPMU_MODE_OFF},
{"self", XENPMU_MODE_SELF},
{"hv", XENPMU_MODE_HV},
{"all", XENPMU_MODE_ALL}
};
static ssize_t pmu_mode_store(struct hyp_sysfs_attr *attr,
const char *buffer, size_t len)
{
int ret;
struct xen_pmu_params xp;
int i;
for (i = 0; i < ARRAY_SIZE(pmu_modes); i++) {
if (strncmp(buffer, pmu_modes[i].name, len - 1) == 0) {
xp.val = pmu_modes[i].mode;
break;
}
}
if (i == ARRAY_SIZE(pmu_modes))
return -EINVAL;
xp.version.maj = XENPMU_VER_MAJ;
xp.version.min = XENPMU_VER_MIN;
ret = HYPERVISOR_xenpmu_op(XENPMU_mode_set, &xp);
if (ret)
return ret;
return len;
}
static ssize_t pmu_mode_show(struct hyp_sysfs_attr *attr, char *buffer)
{
int ret;
struct xen_pmu_params xp;
int i;
uint32_t mode;
xp.version.maj = XENPMU_VER_MAJ;
xp.version.min = XENPMU_VER_MIN;
ret = HYPERVISOR_xenpmu_op(XENPMU_mode_get, &xp);
if (ret)
return ret;
mode = (uint32_t)xp.val;
for (i = 0; i < ARRAY_SIZE(pmu_modes); i++) {
if (mode == pmu_modes[i].mode)
return sprintf(buffer, "%s\n", pmu_modes[i].name);
}
return -EINVAL;
}
HYPERVISOR_ATTR_RW(pmu_mode);
static ssize_t pmu_features_store(struct hyp_sysfs_attr *attr,
const char *buffer, size_t len)
{
int ret;
uint32_t features;
struct xen_pmu_params xp;
ret = kstrtou32(buffer, 0, &features);
if (ret)
return ret;
xp.val = features;
xp.version.maj = XENPMU_VER_MAJ;
xp.version.min = XENPMU_VER_MIN;
ret = HYPERVISOR_xenpmu_op(XENPMU_feature_set, &xp);
if (ret)
return ret;
return len;
}
static ssize_t pmu_features_show(struct hyp_sysfs_attr *attr, char *buffer)
{
int ret;
struct xen_pmu_params xp;
xp.version.maj = XENPMU_VER_MAJ;
xp.version.min = XENPMU_VER_MIN;
ret = HYPERVISOR_xenpmu_op(XENPMU_feature_get, &xp);
if (ret)
return ret;
return sprintf(buffer, "0x%x\n", (uint32_t)xp.val);
}
HYPERVISOR_ATTR_RW(pmu_features);
static struct attribute *xen_pmu_attrs[] = {
&pmu_mode_attr.attr,
&pmu_features_attr.attr,
NULL
};
static const struct attribute_group xen_pmu_group = {
.name = "pmu",
.attrs = xen_pmu_attrs,
};
static int __init xen_pmu_init(void)
{
return sysfs_create_group(hypervisor_kobj, &xen_pmu_group);
}
static void xen_pmu_destroy(void)
{
sysfs_remove_group(hypervisor_kobj, &xen_pmu_group);
}
#endif
static int __init hyper_sysfs_init(void)
{
int ret;
@ -390,7 +513,15 @@ static int __init hyper_sysfs_init(void)
ret = xen_properties_init();
if (ret)
goto prop_out;
#ifdef CONFIG_XEN_HAVE_VPMU
if (xen_initial_domain()) {
ret = xen_pmu_init();
if (ret) {
xen_properties_destroy();
goto prop_out;
}
}
#endif
goto out;
prop_out:
@ -407,6 +538,9 @@ out:
static void __exit hyper_sysfs_exit(void)
{
#ifdef CONFIG_XEN_HAVE_VPMU
xen_pmu_destroy();
#endif
xen_properties_destroy();
xen_compilation_destroy();
xen_sysfs_uuid_destroy();

1
include/xen/interface/xen.h
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@ -80,6 +80,7 @@
#define __HYPERVISOR_kexec_op 37
#define __HYPERVISOR_tmem_op 38
#define __HYPERVISOR_xc_reserved_op 39 /* reserved for XenClient */
#define __HYPERVISOR_xenpmu_op 40
/* Architecture-specific hypercall definitions. */
#define __HYPERVISOR_arch_0 48

59
include/xen/interface/xenpmu.h Normal file
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@ -0,0 +1,59 @@
#ifndef __XEN_PUBLIC_XENPMU_H__
#define __XEN_PUBLIC_XENPMU_H__
#include "xen.h"
#define XENPMU_VER_MAJ 0
#define XENPMU_VER_MIN 1
/*
* ` enum neg_errnoval
* ` HYPERVISOR_xenpmu_op(enum xenpmu_op cmd, struct xenpmu_params *args);
*
* @cmd == XENPMU_* (PMU operation)
* @args == struct xenpmu_params
*/
/* ` enum xenpmu_op { */
#define XENPMU_mode_get 0 /* Also used for getting PMU version */
#define XENPMU_mode_set 1
#define XENPMU_feature_get 2
#define XENPMU_feature_set 3
#define XENPMU_init 4
#define XENPMU_finish 5
/* ` } */
/* Parameters structure for HYPERVISOR_xenpmu_op call */
struct xen_pmu_params {
/* IN/OUT parameters */
struct {
uint32_t maj;
uint32_t min;
} version;
uint64_t val;
/* IN parameters */
uint32_t vcpu;
uint32_t pad;
};
/* PMU modes:
* - XENPMU_MODE_OFF: No PMU virtualization
* - XENPMU_MODE_SELF: Guests can profile themselves
* - XENPMU_MODE_HV: Guests can profile themselves, dom0 profiles
* itself and Xen
* - XENPMU_MODE_ALL: Only dom0 has access to VPMU and it profiles
* everyone: itself, the hypervisor and the guests.
*/
#define XENPMU_MODE_OFF 0
#define XENPMU_MODE_SELF (1<<0)
#define XENPMU_MODE_HV (1<<1)
#define XENPMU_MODE_ALL (1<<2)
/*
* PMU features:
* - XENPMU_FEATURE_INTEL_BTS: Intel BTS support (ignored on AMD)
*/
#define XENPMU_FEATURE_INTEL_BTS 1
#endif /* __XEN_PUBLIC_XENPMU_H__ */