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authorHeinz Graalfs <graalfs@linux.vnet.ibm.com>2013-06-12 13:54:56 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2013-06-17 17:10:23 +0200
commitb764bb1c50c279b95a486d338418f7fda74fff71 (patch)
tree3437841e26cc513f55f6366aebf533f57bbaea6e /arch/s390
parentd0321a24bf10e2299a997c4747b924f79f70a232 (diff)
downloadop-kernel-dev-b764bb1c50c279b95a486d338418f7fda74fff71.zip
op-kernel-dev-b764bb1c50c279b95a486d338418f7fda74fff71.tar.gz
KVM: s390,perf: Detect if perf samples belong to KVM host or guest
This patch is based on an original patch of David Hildenbrand. The perf core implementation calls architecture specific code in order to ask for specific information for a particular sample: perf_instruction_pointer() When perf core code asks for the instruction pointer, architecture specific code must detect if a KVM guest was running when the sample was taken. A sample can be associated with a KVM guest when the PSW supervisor state bit is set and the PSW instruction pointer part contains the address of 'sie_exit'. A KVM guest's instruction pointer information is then retrieved via gpsw entry pointed to by the sie control-block. perf_misc_flags() perf code code calls this function in order to associate the kernel vs. user state infomation with a particular sample. Architecture specific code must also first detectif a KVM guest was running at the time the sample was taken. Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/kvm_host.h1
-rw-r--r--arch/s390/include/asm/perf_event.h10
-rw-r--r--arch/s390/kernel/entry64.S1
-rw-r--r--arch/s390/kernel/perf_event.c52
-rw-r--r--arch/s390/kernel/s390_ksyms.c1
5 files changed, 65 insertions, 0 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index d3ffd7e..4339069 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -275,4 +275,5 @@ struct kvm_arch{
};
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
+extern char sie_exit;
#endif
diff --git a/arch/s390/include/asm/perf_event.h b/arch/s390/include/asm/perf_event.h
index 5f0173a..1141fb3 100644
--- a/arch/s390/include/asm/perf_event.h
+++ b/arch/s390/include/asm/perf_event.h
@@ -14,3 +14,13 @@
/* Per-CPU flags for PMU states */
#define PMU_F_RESERVED 0x1000
#define PMU_F_ENABLED 0x2000
+
+#ifdef CONFIG_64BIT
+
+/* Perf callbacks */
+struct pt_regs;
+extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
+extern unsigned long perf_misc_flags(struct pt_regs *regs);
+#define perf_misc_flags(regs) perf_misc_flags(regs)
+
+#endif /* CONFIG_64BIT */
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 51d99ac..b094ced 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -964,6 +964,7 @@ sie_done:
# See also HANDLE_SIE_INTERCEPT
rewind_pad:
nop 0
+ .globl sie_exit
sie_exit:
lg %r14,__SF_EMPTY+8(%r15) # load guest register save area
stmg %r0,%r13,0(%r14) # save guest gprs 0-13
diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index f58f37f..a6fc037 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/perf_event.h>
+#include <linux/kvm_host.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <asm/irq.h>
@@ -39,6 +40,57 @@ int perf_num_counters(void)
}
EXPORT_SYMBOL(perf_num_counters);
+static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
+{
+ struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];
+
+ if (!stack)
+ return NULL;
+
+ return (struct kvm_s390_sie_block *) stack->empty1[0];
+}
+
+static bool is_in_guest(struct pt_regs *regs)
+{
+ unsigned long ip = instruction_pointer(regs);
+
+ if (user_mode(regs))
+ return false;
+
+ return ip == (unsigned long) &sie_exit;
+}
+
+static unsigned long guest_is_user_mode(struct pt_regs *regs)
+{
+ return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
+}
+
+static unsigned long instruction_pointer_guest(struct pt_regs *regs)
+{
+ return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
+}
+
+unsigned long perf_instruction_pointer(struct pt_regs *regs)
+{
+ return is_in_guest(regs) ? instruction_pointer_guest(regs)
+ : instruction_pointer(regs);
+}
+
+static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
+{
+ return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
+ : PERF_RECORD_MISC_GUEST_KERNEL;
+}
+
+unsigned long perf_misc_flags(struct pt_regs *regs)
+{
+ if (is_in_guest(regs))
+ return perf_misc_guest_flags(regs);
+
+ return user_mode(regs) ? PERF_RECORD_MISC_USER
+ : PERF_RECORD_MISC_KERNEL;
+}
+
void perf_event_print_debug(void)
{
struct cpumf_ctr_info cf_info;
diff --git a/arch/s390/kernel/s390_ksyms.c b/arch/s390/kernel/s390_ksyms.c
index 9bdbcef..3bac589 100644
--- a/arch/s390/kernel/s390_ksyms.c
+++ b/arch/s390/kernel/s390_ksyms.c
@@ -7,6 +7,7 @@ EXPORT_SYMBOL(_mcount);
#endif
#if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
EXPORT_SYMBOL(sie64a);
+EXPORT_SYMBOL(sie_exit);
#endif
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memset);
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