From: Heinz Graalfs <graalfs@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 1 +
arch/s390/include/asm/perf_event.h | 10 ++++++++
arch/s390/kernel/entry64.S | 1 +
arch/s390/kernel/perf_event.c | 52 ++++++++++++++++++++++++++++++++++++++
arch/s390/kernel/s390_ksyms.c | 1 +
5 files changed, 65 insertions(+)
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);
--
1.8.1.6
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