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Commit 39447b38 authored Apr 19, 2010 by Zhang, Yanmin Committed by Avi Kivity Apr 19, 2010

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: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Avi 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 */