Commit 39447b38 authored by Zhang, Yanmin's avatar Zhang, Yanmin Committed by Avi Kivity
Browse files

perf: Enhance perf to allow for guest statistic collection from host 



Below patch introduces perf_guest_info_callbacks and related
register/unregister functions. Add more PERF_RECORD_MISC_XXX bits
meaning guest kernel and guest user space.

Signed-off-by: default avatarZhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent b5a80b7e

arch/x86/include/asm/perf_event.h

+4 −11
Original line number Diff line number Diff line
@@ -135,17 +135,10 @@ extern void perf_events_lapic_init(void); 
 */

#define PERF_EFLAGS_EXACT	(1UL << 3)



#define perf_misc_flags(regs)				\

({	int misc = 0;					\

	if (user_mode(regs))				\

		misc |= PERF_RECORD_MISC_USER;		\

	else						\

		misc |= PERF_RECORD_MISC_KERNEL;	\

	if (regs->flags & PERF_EFLAGS_EXACT)		\

		misc |= PERF_RECORD_MISC_EXACT;		\

	misc; })



#define perf_instruction_pointer(regs)	((regs)->ip)

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)



#else

static inline void init_hw_perf_events(void)		{ }

arch/x86/kernel/cpu/perf_event.c

+31 −0
Original line number Diff line number Diff line
@@ -1720,6 +1720,11 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) 
{

	struct perf_callchain_entry *entry;



	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {

		/* TODO: We don't support guest os callchain now */

		return NULL;

	}



	if (in_nmi())

		entry = &__get_cpu_var(pmc_nmi_entry);

	else
@@ -1743,3 +1748,29 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski 
	regs->cs = __KERNEL_CS;

	local_save_flags(regs->flags);

}



unsigned long perf_instruction_pointer(struct pt_regs *regs)

{

	unsigned long ip;

	if (perf_guest_cbs && perf_guest_cbs->is_in_guest())

		ip = perf_guest_cbs->get_guest_ip();

	else

		ip = instruction_pointer(regs);

	return ip;

}



unsigned long perf_misc_flags(struct pt_regs *regs)

{

	int misc = 0;

	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {

		misc |= perf_guest_cbs->is_user_mode() ?

			PERF_RECORD_MISC_GUEST_USER :

			PERF_RECORD_MISC_GUEST_KERNEL;

	} else

		misc |= user_mode(regs) ? PERF_RECORD_MISC_USER :

			PERF_RECORD_MISC_KERNEL;

	if (regs->flags & PERF_EFLAGS_EXACT)

		misc |= PERF_RECORD_MISC_EXACT;



	return misc;

}

include/linux/perf_event.h

+20 −1
Original line number Diff line number Diff line
@@ -288,11 +288,13 @@ struct perf_event_mmap_page { 
	__u64	data_tail;		/* user-space written tail */

};



#define PERF_RECORD_MISC_CPUMODE_MASK		(3 << 0)

#define PERF_RECORD_MISC_CPUMODE_MASK		(7 << 0)

#define PERF_RECORD_MISC_CPUMODE_UNKNOWN	(0 << 0)

#define PERF_RECORD_MISC_KERNEL			(1 << 0)

#define PERF_RECORD_MISC_USER			(2 << 0)

#define PERF_RECORD_MISC_HYPERVISOR		(3 << 0)

#define PERF_RECORD_MISC_GUEST_KERNEL		(4 << 0)

#define PERF_RECORD_MISC_GUEST_USER		(5 << 0)



#define PERF_RECORD_MISC_EXACT			(1 << 14)

/*
@@ -446,6 +448,12 @@ enum perf_callchain_context { 
# include <asm/perf_event.h>

#endif



struct perf_guest_info_callbacks {

	int (*is_in_guest) (void);

	int (*is_user_mode) (void);

	unsigned long (*get_guest_ip) (void);

};



#ifdef CONFIG_HAVE_HW_BREAKPOINT

#include <asm/hw_breakpoint.h>

#endif
@@ -932,6 +940,12 @@ static inline void perf_event_mmap(struct vm_area_struct *vma) 
		__perf_event_mmap(vma);

}



extern struct perf_guest_info_callbacks *perf_guest_cbs;

extern int perf_register_guest_info_callbacks(

		struct perf_guest_info_callbacks *);

extern int perf_unregister_guest_info_callbacks(

		struct perf_guest_info_callbacks *);



extern void perf_event_comm(struct task_struct *tsk);

extern void perf_event_fork(struct task_struct *tsk);
@@ -1001,6 +1015,11 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, 
static inline void

perf_bp_event(struct perf_event *event, void *data)			{ }



static inline int perf_register_guest_info_callbacks

(struct perf_guest_info_callbacks *) {return 0; }

static inline int perf_unregister_guest_info_callbacks

(struct perf_guest_info_callbacks *) {return 0; }



static inline void perf_event_mmap(struct vm_area_struct *vma)		{ }

static inline void perf_event_comm(struct task_struct *tsk)		{ }

static inline void perf_event_fork(struct task_struct *tsk)		{ }

kernel/perf_event.c

+22 −1
Original line number Diff line number Diff line
@@ -2797,6 +2797,27 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski 
}





/*

 * We assume there is only KVM supporting the callbacks.

 * Later on, we might change it to a list if there is

 * another virtualization implementation supporting the callbacks.

 */

struct perf_guest_info_callbacks *perf_guest_cbs;



int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)

{

	perf_guest_cbs = cbs;

	return 0;

}

EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);



int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)

{

	perf_guest_cbs = NULL;

	return 0;

}

EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);



/*

 * Output

 */
@@ -3749,7 +3770,7 @@ void __perf_event_mmap(struct vm_area_struct *vma) 
		.event_id  = {

			.header = {

				.type = PERF_RECORD_MMAP,

				.misc = 0,

				.misc = PERF_RECORD_MISC_USER,

				/* .size */

			},

			/* .pid */

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