perf/core: Rework guest callbacks to prepare for static_call support

To prepare for using static_calls to optimize perf's guest callbacks,
replace ->is_in_guest and ->is_user_mode with a new multiplexed hook
->state, tweak ->handle_intel_pt_intr to play nice with being called when
there is no active guest, and drop "guest" from ->get_guest_ip.

Return '0' from ->state and ->handle_intel_pt_intr to indicate "not in
guest" so that DEFINE_STATIC_CALL_RET0 can be used to define the static
calls, i.e. no callback == !guest.

[sean: extracted from static_call patch, fixed get_ip() bug, wrote changelog]
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20211111020738.2512932-7-seanjc@google.com

1 files changed, 7 insertions, 6 deletions

diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
index 86d9f2013172..274dc3e11b6d 100644
--- a/arch/arm64/kernel/perf_callchain.c
+++ b/arch/arm64/kernel/perf_callchain.c
@@ -104,7 +104,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
 {
 	struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs();
 
-	if (guest_cbs && guest_cbs->is_in_guest()) {
+	if (guest_cbs && guest_cbs->state()) {
 		/* We don't support guest os callchain now */
 		return;
 	}
@@ -152,7 +152,7 @@ void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
 	struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs();
 	struct stackframe frame;
 
-	if (guest_cbs && guest_cbs->is_in_guest()) {
+	if (guest_cbs && guest_cbs->state()) {
 		/* We don't support guest os callchain now */
 		return;
 	}
@@ -165,8 +165,8 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs)
 {
 	struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs();
 
-	if (guest_cbs && guest_cbs->is_in_guest())
-		return guest_cbs->get_guest_ip();
+	if (guest_cbs && guest_cbs->state())
+		return guest_cbs->get_ip();
 
 	return instruction_pointer(regs);
 }
@@ -174,10 +174,11 @@ unsigned long perf_instruction_pointer(struct pt_regs *regs)
 unsigned long perf_misc_flags(struct pt_regs *regs)
 {
 	struct perf_guest_info_callbacks *guest_cbs = perf_get_guest_cbs();
+	unsigned int guest_state = guest_cbs ? guest_cbs->state() : 0;
 	int misc = 0;
 
-	if (guest_cbs && guest_cbs->is_in_guest()) {
-		if (guest_cbs->is_user_mode())
+	if (guest_state) {
+		if (guest_state & PERF_GUEST_USER)
 			misc |= PERF_RECORD_MISC_GUEST_USER;
 		else
 			misc |= PERF_RECORD_MISC_GUEST_KERNEL;