Re: [PATCH v1 2/5] xen/PMU: Sysfs interface for setting Xen PMU mode

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Sep 10, 2013 at 11:31:47AM -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@oracle.com>
> ---
>  arch/x86/include/asm/xen/hypercall.h |   6 ++
>  arch/x86/xen/xen-head.S              |   5 +-
>  drivers/xen/sys-hypervisor.c         | 118 +++++++++++++++++++++++++++++++++++
>  include/xen/interface/xen.h          |   1 +
>  include/xen/interface/xenpmu.h       |  44 +++++++++++++
>  5 files changed, 173 insertions(+), 1 deletion(-)
>  create mode 100644 include/xen/interface/xenpmu.h
> 
> diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
> index e709884..f022cef 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/xen-head.S b/arch/x86/xen/xen-head.S
> index 7faed58..f2415e6 100644
> --- a/arch/x86/xen/xen-head.S
> +++ b/arch/x86/xen/xen-head.S
> @@ -73,8 +73,11 @@ NEXT_HYPERCALL(sysctl)
>  NEXT_HYPERCALL(domctl)
>  NEXT_HYPERCALL(kexec_op)
>  NEXT_HYPERCALL(tmem_op) /* 38 */
> +ENTRY(xenclient_rsvd)
> +	.skip 32
> +NEXT_HYPERCALL(xenpmu_op) /* 40 */
>  ENTRY(xen_hypercall_rsvr)
> -	.skip 320
> +	.skip 256
>  NEXT_HYPERCALL(mca) /* 48 */
>  NEXT_HYPERCALL(arch_1)
>  NEXT_HYPERCALL(arch_2)
> diff --git a/drivers/xen/sys-hypervisor.c b/drivers/xen/sys-hypervisor.c
> index 96453f8..2218154 100644
> --- a/drivers/xen/sys-hypervisor.c
> +++ b/drivers/xen/sys-hypervisor.c
> @@ -20,6 +20,7 @@
>  #include <xen/xenbus.h>
>  #include <xen/interface/xen.h>
>  #include <xen/interface/version.h>
> +#include <xen/interface/xenpmu.h>
>  
>  #define HYPERVISOR_ATTR_RO(_name) \
>  static struct hyp_sysfs_attr  _name##_attr = __ATTR_RO(_name)
> @@ -368,6 +369,115 @@ static void xen_properties_destroy(void)
>  	sysfs_remove_group(hypervisor_kobj, &xen_properties_group);
>  }
>  
> +struct pmu_mode {
> +	const char *name;
> +	uint32_t mode;
> +};
> +struct pmu_mode pmu_modes[] = {
> +	{"enable", VPMU_ON},
> +	{"priv_enable", VPMU_PRIV},
> +	{"disable", 0}
> +};
> +static ssize_t pmu_mode_store(struct hyp_sysfs_attr *attr,
> +			      const char *buffer, size_t len)
> +{
> +	int ret;
> +	struct xenpmu_params xp;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(pmu_modes); i++) {
> +		if (!strncmp(buffer, pmu_modes[i].name,
> +			     strlen(pmu_modes[i].name))) {
> +			xp.control = pmu_modes[i].mode;
> +			break;
> +		}
> +	}
> +
> +	if (i == ARRAY_SIZE(pmu_modes))
> +		return -EINVAL;
> +
> +	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 xenpmu_params xp;
> +	int i;
> +	uint32_t mode;
> +
> +	ret = HYPERVISOR_xenpmu_op(XENPMU_mode_get, &xp);
> +	if (ret)
> +		return ret;
> +
> +	mode = (uint32_t)xp.control & VPMU_MODE_MASK;
> +	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_flags_store(struct hyp_sysfs_attr *attr,
> +			      const char *buffer, size_t len)
> +{
> +	int ret;
> +	uint32_t flags;
> +	struct xenpmu_params xp;
> +
> +	ret = kstrtou32(buffer, 0, &flags);
> +	if (ret)
> +		return ret;
> +
> +	xp.control = flags;
> +	ret = HYPERVISOR_xenpmu_op(XENPMU_flags_set, &xp);
> +	if (ret)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static ssize_t pmu_flags_show(struct hyp_sysfs_attr *attr, char *buffer)
> +{
> +	int ret;
> +	struct xenpmu_params xp;
> +
> +	ret = HYPERVISOR_xenpmu_op(XENPMU_flags_get, &xp);
> +	if (ret)
> +		return ret;
> +
> +	return sprintf(buffer, "0x%x\n", (uint32_t)xp.control);
> +}
> +HYPERVISOR_ATTR_RW(pmu_flags);
> +
> +static struct attribute *xen_pmu_attrs[] = {
> +	&pmu_mode_attr.attr,
> +	&pmu_flags_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);
> +}
> +
>  static int __init hyper_sysfs_init(void)
>  {
>  	int ret;
> @@ -390,9 +500,16 @@ static int __init hyper_sysfs_init(void)
>  	ret = xen_properties_init();
>  	if (ret)
>  		goto prop_out;
> +	if (xen_initial_domain()) {
> +		ret = xen_pmu_init();
> +		if (ret)
> +			goto pmu_out;
> +	}
>  
>  	goto out;
>  
> +pmu_out:
> +	xen_properties_destroy();
>  prop_out:
>  	xen_sysfs_uuid_destroy();
>  uuid_out:
> @@ -407,6 +524,7 @@ out:
>  
>  static void __exit hyper_sysfs_exit(void)
>  {
> +	xen_pmu_destroy();
>  	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 53ec416..c29d427 100644
> --- a/include/xen/interface/xen.h
> +++ b/include/xen/interface/xen.h
> @@ -58,6 +58,7 @@
>  #define __HYPERVISOR_physdev_op           33
>  #define __HYPERVISOR_hvm_op               34
>  #define __HYPERVISOR_tmem_op              38
> +#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..63c42b1
> --- /dev/null
> +++ b/include/xen/interface/xenpmu.h
> @@ -0,0 +1,44 @@
> +#ifndef __XEN_PUBLIC_XENPMU_H__
> +#define __XEN_PUBLIC_XENPMU_H__
> +
> +#include <asm/msr.h>
> +
> +#include "xen.h"
> +
> +#define XENPMU_VER_MAJ    0
> +#define XENPMU_VER_MIN    0
> +
> +/* HYPERVISOR_xenpmu_op commands */
> +#define XENPMU_mode_get        0
> +#define XENPMU_mode_set        1
> +#define XENPMU_flags_get       2
> +#define XENPMU_flags_set       3
> +
> +/* Parameter structure for HYPERVISOR_xenpmu_op call */
> +struct xenpmu_params {
> +	union {
> +		struct version {
> +			uint8_t maj;
> +			uint8_t min;
> +		} version;
> +		uint64_t pad;
> +	};
> +	uint64_t control;
> +};
> +
> +/* VPMU modes */
> +#define VPMU_MODE_MASK     0xff
> +#define VPMU_OFF           0
> +/* guests can profile themselves, (dom0 profiles itself and Xen) */
> +#define VPMU_ON            (1<<0)
> +/*
> + * Only dom0 has access to VPMU and it profiles everyone: itself,
> + * the hypervisor and the guests.
> + */
> +#define VPMU_PRIV          (1<<1)
> +
> +/* VPMU flags */
> +#define VPMU_FLAGS_MASK    ((uint32_t)(~VPMU_MODE_MASK))
> +#define VPMU_INTEL_BTS     (1<<8) /* Ignored on AMD */
> +
> +#endif /* __XEN_PUBLIC_XENPMU_H__ */

Looks OK to me if there are no changes to the hypervisor ABI.
> -- 
> 1.8.1.4
>