[PATCH v4 09/17] x86/VPMU: Interface for setting PMU mode and flags

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

Add runtime interface for setting PMU mode and flags. Three main modes are
provided:
* PMU off
* PMU on: Guests can access PMU MSRs and receive PMU interrupts. dom0
  profiles itself and the hypervisor.
* dom0-only PMU: dom0 collects samples for both itself and guests.

For feature flags only Intel's BTS is currently supported.

Mode and flags are set via HYPERVISOR_xenpmu_op hypercall.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
 xen/arch/x86/hvm/svm/vpmu.c        |  2 +-
 xen/arch/x86/hvm/vmx/vpmu_core2.c  |  4 +-
 xen/arch/x86/hvm/vpmu.c            | 77 ++++++++++++++++++++++++++++++++++----
 xen/arch/x86/x86_64/compat/entry.S |  4 ++
 xen/arch/x86/x86_64/entry.S        |  4 ++
 xen/include/asm-x86/hvm/vpmu.h     |  9 +----
 xen/include/public/xen.h           |  1 +
 xen/include/public/xenpmu.h        | 51 +++++++++++++++++++++++++
 xen/include/xen/hypercall.h        |  4 ++
 9 files changed, 138 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/vpmu.c b/xen/arch/x86/hvm/svm/vpmu.c
index bf7f1f6..3dd6911 100644
--- a/xen/arch/x86/hvm/svm/vpmu.c
+++ b/xen/arch/x86/hvm/svm/vpmu.c
@@ -471,7 +471,7 @@ int svm_vpmu_initialise(struct vcpu *v, unsigned int vpmu_flags)
     int ret = 0;
 
     /* vpmu enabled? */
-    if ( !vpmu_flags )
+    if ( vpmu_flags == XENPMU_MODE_OFF )
         return 0;
 
     switch ( family )
diff --git a/xen/arch/x86/hvm/vmx/vpmu_core2.c b/xen/arch/x86/hvm/vmx/vpmu_core2.c
index 3c3bedc..9e0e743 100644
--- a/xen/arch/x86/hvm/vmx/vpmu_core2.c
+++ b/xen/arch/x86/hvm/vmx/vpmu_core2.c
@@ -707,7 +707,7 @@ static int core2_vpmu_initialise(struct vcpu *v, unsigned int vpmu_flags)
     u64 msr_content;
     struct cpuinfo_x86 *c = &current_cpu_data;
 
-    if ( !(vpmu_flags & VPMU_BOOT_BTS) )
+    if ( !(vpmu_flags & (XENPMU_FEATURE_INTEL_BTS << XENPMU_FEATURE_SHIFT)) )
         goto func_out;
     /* Check the 'Debug Store' feature in the CPUID.EAX[1]:EDX[21] */
     if ( cpu_has(c, X86_FEATURE_DS) )
@@ -826,7 +826,7 @@ int vmx_vpmu_initialise(struct vcpu *v, unsigned int vpmu_flags)
     int ret = 0;
 
     vpmu->arch_vpmu_ops = &core2_no_vpmu_ops;
-    if ( !vpmu_flags )
+    if ( vpmu_flags == XENPMU_MODE_OFF )
         return 0;
 
     if ( family == 6 )
diff --git a/xen/arch/x86/hvm/vpmu.c b/xen/arch/x86/hvm/vpmu.c
index 8c263a5..309f858 100644
--- a/xen/arch/x86/hvm/vpmu.c
+++ b/xen/arch/x86/hvm/vpmu.c
@@ -21,6 +21,7 @@
 #include <xen/config.h>
 #include <xen/sched.h>
 #include <xen/xenoprof.h>
+#include <xen/guest_access.h>
 #include <asm/regs.h>
 #include <asm/types.h>
 #include <asm/msr.h>
@@ -38,7 +39,7 @@
  * "vpmu=off" : vpmu generally disabled
  * "vpmu=bts" : vpmu enabled and Intel BTS feature switched on.
  */
-static unsigned int __read_mostly opt_vpmu_enabled;
+uint32_t __read_mostly vpmu_mode = XENPMU_MODE_OFF;
 static void parse_vpmu_param(char *s);
 custom_param("vpmu", parse_vpmu_param);
 
@@ -52,7 +53,7 @@ static void __init parse_vpmu_param(char *s)
         break;
     default:
         if ( !strcmp(s, "bts") )
-            opt_vpmu_enabled |= VPMU_BOOT_BTS;
+            vpmu_mode |= XENPMU_FEATURE_INTEL_BTS << XENPMU_FEATURE_SHIFT;
         else if ( *s )
         {
             printk("VPMU: unknown flag: %s - vpmu disabled!\n", s);
@@ -60,7 +61,7 @@ static void __init parse_vpmu_param(char *s)
         }
         /* fall through */
     case 1:
-        opt_vpmu_enabled |= VPMU_BOOT_ENABLED;
+        vpmu_mode |= XENPMU_MODE_ON;
         break;
     }
 }
@@ -234,19 +235,19 @@ void vpmu_initialise(struct vcpu *v)
     switch ( vendor )
     {
     case X86_VENDOR_AMD:
-        if ( svm_vpmu_initialise(v, opt_vpmu_enabled) != 0 )
-            opt_vpmu_enabled = 0;
+        if ( svm_vpmu_initialise(v, vpmu_mode) != 0 )
+            vpmu_mode = XENPMU_MODE_OFF;
         return;
 
     case X86_VENDOR_INTEL:
-        if ( vmx_vpmu_initialise(v, opt_vpmu_enabled) != 0 )
-            opt_vpmu_enabled = 0;
+        if ( vmx_vpmu_initialise(v, vpmu_mode) != 0 )
+            vpmu_mode = XENPMU_MODE_OFF;
         return;
 
     default:
         printk("VPMU: Initialization failed. "
                "Unknown CPU vendor %d\n", vendor);
-        opt_vpmu_enabled = 0;
+        vpmu_mode = XENPMU_MODE_OFF;
         return;
     }
 }
@@ -268,3 +269,63 @@ void vpmu_dump(struct vcpu *v)
         vpmu->arch_vpmu_ops->arch_vpmu_dump(v);
 }
 
+long do_xenpmu_op(int op, XEN_GUEST_HANDLE_PARAM(xen_pmu_params_t) arg)
+{
+    int ret = -EINVAL;
+    xen_pmu_params_t pmu_params;
+    uint32_t mode;
+
+    switch ( op )
+    {
+    case XENPMU_mode_set:
+        if ( !is_control_domain(current->domain) )
+            return -EPERM;
+
+        if ( copy_from_guest(&pmu_params, arg, 1) )
+            return -EFAULT;
+
+        mode = (uint32_t)pmu_params.d.val & XENPMU_MODE_MASK;
+        if ( mode & ~XENPMU_MODE_ON )
+            return -EINVAL;
+
+        vpmu_mode &= ~XENPMU_MODE_MASK;
+        vpmu_mode |= mode;
+
+        ret = 0;
+        break;
+
+    case XENPMU_mode_get:
+        pmu_params.d.val = vpmu_mode & XENPMU_MODE_MASK;
+        pmu_params.v.version.maj = XENPMU_VER_MAJ;
+        pmu_params.v.version.min = XENPMU_VER_MIN;
+        if ( copy_to_guest(arg, &pmu_params, 1) )
+            return -EFAULT;
+        ret = 0;
+        break;
+
+    case XENPMU_feature_set:
+        if ( !is_control_domain(current->domain) )
+            return -EPERM;
+
+        if ( copy_from_guest(&pmu_params, arg, 1) )
+            return -EFAULT;
+
+        if ( (uint32_t)pmu_params.d.val & ~XENPMU_FEATURE_INTEL_BTS )
+            return -EINVAL;
+
+        vpmu_mode &= ~XENPMU_FEATURE_MASK;
+        vpmu_mode |= (uint32_t)pmu_params.d.val << XENPMU_FEATURE_SHIFT;
+
+        ret = 0;
+        break;
+
+    case XENPMU_feature_get:
+        pmu_params.d.val = vpmu_mode & XENPMU_FEATURE_MASK;
+        if ( copy_to_guest(arg, &pmu_params, 1) )
+            return -EFAULT;
+        ret = 0;
+        break;
+     }
+
+    return ret;
+}
diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
index 594b0b9..07c736d 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -416,6 +416,8 @@ ENTRY(compat_hypercall_table)
         .quad do_domctl
         .quad compat_kexec_op
         .quad do_tmem_op
+        .quad do_ni_hypercall           /* reserved for XenClient */
+        .quad do_xenpmu_op              /* 40 */
         .rept __HYPERVISOR_arch_0-((.-compat_hypercall_table)/8)
         .quad compat_ni_hypercall
         .endr
@@ -464,6 +466,8 @@ ENTRY(compat_hypercall_args_table)
         .byte 1 /* do_domctl                */
         .byte 2 /* compat_kexec_op          */
         .byte 1 /* do_tmem_op               */
+        .byte 0 /* reserved for XenClient   */
+        .byte 2 /* do_xenpmu_op             */  /* 40 */
         .rept __HYPERVISOR_arch_0-(.-compat_hypercall_args_table)
         .byte 0 /* compat_ni_hypercall      */
         .endr
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 3ea4683..c36ffce 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -757,6 +757,8 @@ ENTRY(hypercall_table)
         .quad do_domctl
         .quad do_kexec_op
         .quad do_tmem_op
+        .quad do_ni_hypercall       /* reserved for XenClient */
+        .quad do_xenpmu_op          /* 40 */
         .rept __HYPERVISOR_arch_0-((.-hypercall_table)/8)
         .quad do_ni_hypercall
         .endr
@@ -805,6 +807,8 @@ ENTRY(hypercall_args_table)
         .byte 1 /* do_domctl            */
         .byte 2 /* do_kexec             */
         .byte 1 /* do_tmem_op           */
+        .byte 0 /* reserved for XenClient */
+        .byte 2 /* do_xenpmu_op         */  /* 40 */
         .rept __HYPERVISOR_arch_0-(.-hypercall_args_table)
         .byte 0 /* do_ni_hypercall      */
         .endr
diff --git a/xen/include/asm-x86/hvm/vpmu.h b/xen/include/asm-x86/hvm/vpmu.h
index 8646fd6..8c5c772 100644
--- a/xen/include/asm-x86/hvm/vpmu.h
+++ b/xen/include/asm-x86/hvm/vpmu.h
@@ -24,13 +24,6 @@
 
 #include <public/xenpmu.h>
 
-/*
- * Flag bits given as a string on the hypervisor boot parameter 'vpmu'.
- * See arch/x86/hvm/vpmu.c.
- */
-#define VPMU_BOOT_ENABLED 0x1    /* vpmu generally enabled. */
-#define VPMU_BOOT_BTS     0x2    /* Intel BTS feature wanted. */
-
 #define vcpu_vpmu(vcpu)   (&((vcpu)->arch.vpmu))
 #define vpmu_vcpu(vpmu)   (container_of((vpmu), struct vcpu, arch.vpmu))
 
@@ -98,5 +91,7 @@ void vpmu_dump(struct vcpu *v);
 extern int acquire_pmu_ownership(int pmu_ownership);
 extern void release_pmu_ownership(int pmu_ownership);
 
+extern uint32_t vpmu_mode;
+
 #endif /* __ASM_X86_HVM_VPMU_H_*/
 
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 8c5697e..a00ab21 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -101,6 +101,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
 #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/xen/include/public/xenpmu.h b/xen/include/public/xenpmu.h
index 4757db9..fac29a6 100644
--- a/xen/include/public/xenpmu.h
+++ b/xen/include/public/xenpmu.h
@@ -13,6 +13,57 @@
 #define XENPMU_VER_MAJ    0
 #define XENPMU_VER_MIN    0
 
+/*
+ * ` 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
+/* ` } */
+
+/* Parameters structure for HYPERVISOR_xenpmu_op call */
+struct xen_pmu_params {
+    /* IN/OUT parameters */
+    union {
+        struct version {
+            uint8_t maj;
+            uint8_t min;
+        } version;
+        uint64_t pad;
+    } v;
+    union {
+        uint64_t val;
+        XEN_GUEST_HANDLE(void) valp;
+    } d;
+
+    /* IN parameters */
+    uint64_t vcpu;
+};
+typedef struct xen_pmu_params xen_pmu_params_t;
+DEFINE_XEN_GUEST_HANDLE(xen_pmu_params_t);
+
+/* PMU modes:
+ * - XENPMU_MODE_OFF:   No PMU virtualization
+ * - XENPMU_MODE_ON:    Guests can profile themselves, dom0 profiles
+ *                      itself and Xen
+ */
+#define XENPMU_FEATURE_SHIFT      16
+#define XENPMU_MODE_MASK          ((1U << XENPMU_FEATURE_SHIFT) - 1)
+#define XENPMU_MODE_OFF           0
+#define XENPMU_MODE_ON            (1<<0)
+
+/*
+ * PMU features:
+ * - XENPMU_FEATURE_INTEL_BTS: Intel BTS support (ignored on AMD)
+ */
+#define XENPMU_FEATURE_MASK       ((uint32_t)(~XENPMU_MODE_MASK))
+#define XENPMU_FEATURE_INTEL_BTS  1
 
 /* Shared between hypervisor and PV domain */
 struct xen_pmu_data {
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index a9e5229..acf50e8 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -14,6 +14,7 @@
 #include <public/event_channel.h>
 #include <public/tmem.h>
 #include <public/version.h>
+#include <public/xenpmu.h>
 #include <asm/hypercall.h>
 #include <xsm/xsm.h>
 
@@ -139,6 +140,9 @@ do_tmem_op(
 extern long
 do_xenoprof_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg);
 
+extern long
+do_xenpmu_op(int op, XEN_GUEST_HANDLE_PARAM(xen_pmu_params_t) arg);
+
 #ifdef CONFIG_COMPAT
 
 extern int
-- 
1.8.1.4