xen/PMU: Sysfs interface for setting Xen PMU mode

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>

diff --git a/Documentation/ABI/testing/sysfs-hypervisor-pmu b/Documentation/ABI/testing/sysfs-hypervisor-pmu
new file mode 100644 (file)
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@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

diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index ca08a27b90b3dbcf64dc69515fdadd3734b7a05e..83aea8055119e2f26beb1c909536609d30e88943 100644 (file)
--- 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 7bcf21b865d11421044f6d2ec2bd23c6c5ffb77b..a8ffdb85656f0d86dfd2ee1d941531201527ae41 100644 (file)
--- 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 936760455dd5a49810576d5dc503a1e0aa059285..73708acce3ca78dfeb2da5fa78d6655e8f6554d4 100644 (file)
--- 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 96453f8a85c5543f506ecc128f22e91b3d2dbdbb..b5a7342e0ba5288ddf9e4e3f4fcd4fbcced9df9e 100644 (file)
--- 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;
+};
+
+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();

diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index 8194270edcf00d24052bedcc927b230116eb7a9c..e9d4501d1f5e2ba1d63076bf6cd565ad4d490d6f 100644 (file)
--- 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 (file)
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__ */