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Date: Mon, 10 Aug 2015 10:10:50 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: david.vrabel@...rix.com, kevin.tian@...el.com, jbeulich@...e.com,
dietmar.hahn@...fujitsu.com, stefano.stabellini@...citrix.com,
julien.grall@...rix.com, xen-devel@...ts.xen.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 2/6] xen/PMU: Sysfs interface for setting Xen PMU mode
On Sun, Aug 09, 2015 at 09:31:43PM -0400, Boris Ostrovsky wrote:
> Set Xen's PMU mode via /sys/hypervisor/pmu/pmu_mode. Add XENPMU hypercall.
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> ---
> Documentation/ABI/testing/sysfs-hypervisor-pmu | 23 +++++
> arch/x86/include/asm/xen/hypercall.h | 6 ++
> arch/x86/xen/Kconfig | 1 +
> drivers/xen/Kconfig | 3 +
> drivers/xen/sys-hypervisor.c | 136 ++++++++++++++++++++++++-
> include/xen/interface/xen.h | 1 +
> include/xen/interface/xenpmu.h | 59 +++++++++++
> 7 files changed, 228 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/ABI/testing/sysfs-hypervisor-pmu
> create mode 100644 include/xen/interface/xenpmu.h
>
> diff --git a/Documentation/ABI/testing/sysfs-hypervisor-pmu b/Documentation/ABI/testing/sysfs-hypervisor-pmu
> new file mode 100644
> index 0000000..224faa1
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-hypervisor-pmu
> @@ -0,0 +1,23 @@
> +What: /sys/hypervisor/pmu/pmu_mode
> +Date: August 2015
> +KernelVersion: 4.3
> +Contact: Boris Ostrovsky <boris.ostrovsky@...cle.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@...cle.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
> diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
> index ca08a27..83aea80 100644
> --- a/arch/x86/include/asm/xen/hypercall.h
> +++ b/arch/x86/include/asm/xen/hypercall.h
> @@ -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)
> {
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index e88fda8..049cdda 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -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
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 9367604..73708ac 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -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
> diff --git a/drivers/xen/sys-hypervisor.c b/drivers/xen/sys-hypervisor.c
> index 96453f8..0907275 100644
> --- a/drivers/xen/sys-hypervisor.c
> +++ b/drivers/xen/sys-hypervisor.c
> @@ -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;
> +};
> +
> +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();
> diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
> index a483789..c6399a1 100644
> --- a/include/xen/interface/xen.h
> +++ b/include/xen/interface/xen.h
> @@ -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
> diff --git a/include/xen/interface/xenpmu.h b/include/xen/interface/xenpmu.h
> new file mode 100644
> index 0000000..eac1b49
> --- /dev/null
> +++ b/include/xen/interface/xenpmu.h
> @@ -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__ */
> --
> 1.8.1.4
>
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