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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
This commit is contained in:
Like Xu 2021-11-11 02:07:27 +00:00 committed by Peter Zijlstra
parent 84af21d850
commit b9f5621c95
9 changed files with 84 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
arch/arm64/kernel/perf_callchain.c
View File

@ -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;

35
arch/arm64/kvm/perf.c
View File

@ -13,39 +13,34 @@
DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available);
static int kvm_is_in_guest(void)
static unsigned int kvm_guest_state(void)
{
return kvm_get_running_vcpu() != NULL;
}
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
unsigned int state;
static int kvm_is_user_mode(void)
{
struct kvm_vcpu *vcpu;
if (!vcpu)
return 0;
vcpu = kvm_get_running_vcpu();
state = PERF_GUEST_ACTIVE;
if (!vcpu_mode_priv(vcpu))
state |= PERF_GUEST_USER;
if (vcpu)
return !vcpu_mode_priv(vcpu);
return 0;
return state;
}
static unsigned long kvm_get_guest_ip(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
vcpu = kvm_get_running_vcpu();
if (WARN_ON_ONCE(!vcpu))
return 0;
if (vcpu)
return *vcpu_pc(vcpu);
return 0;
return *vcpu_pc(vcpu);
}
static struct perf_guest_info_callbacks kvm_guest_cbs = {
.is_in_guest = kvm_is_in_guest,
.is_user_mode = kvm_is_user_mode,
.get_guest_ip = kvm_get_guest_ip,
.state = kvm_guest_state,
.get_ip = kvm_get_guest_ip,
};
void kvm_perf_init(void)

13
arch/x86/events/core.c
View File

@ -2772,7 +2772,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
struct unwind_state state;
unsigned long addr;
if (guest_cbs && guest_cbs->is_in_guest()) {
if (guest_cbs && guest_cbs->state()) {
/* TODO: We don't support guest os callchain now */
return;
}
@ -2876,7 +2876,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs
struct stack_frame frame;
const struct stack_frame __user *fp;
if (guest_cbs && guest_cbs->is_in_guest()) {
if (guest_cbs && guest_cbs->state()) {
/* TODO: We don't support guest os callchain now */
return;
}
@ -2955,8 +2955,8 @@ 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 regs->ip + code_segment_base(regs);
}
@ -2964,10 +2964,11 @@ 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;

5
arch/x86/events/intel/core.c
View File

@ -2906,10 +2906,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status)
handled++;
guest_cbs = perf_get_guest_cbs();
if (unlikely(guest_cbs && guest_cbs->is_in_guest() &&
guest_cbs->handle_intel_pt_intr))
guest_cbs->handle_intel_pt_intr();
else
if (likely(!guest_cbs || !guest_cbs->handle_intel_pt_intr()))
intel_pt_interrupt();
}

2
arch/x86/include/asm/kvm_host.h
View File

@ -1895,7 +1895,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu);
int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err);
void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu);
int kvm_is_in_guest(void);
unsigned int kvm_guest_state(void);
void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
u32 size);

2
arch/x86/kvm/pmu.c
View File

@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
* woken up. So we should wake it, but this is impossible from
* NMI context. Do it from irq work instead.
*/
if (!kvm_is_in_guest())
if (!kvm_guest_state())
irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
else
kvm_make_request(KVM_REQ_PMI, pmc->vcpu);

62
arch/x86/kvm/x86.c
View File

@ -8472,44 +8472,48 @@ static void kvm_timer_init(void)
DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu);
int kvm_is_in_guest(void)
{
return __this_cpu_read(current_vcpu) != NULL;
}
static int kvm_is_user_mode(void)
{
int user_mode = 3;
if (__this_cpu_read(current_vcpu))
user_mode = static_call(kvm_x86_get_cpl)(__this_cpu_read(current_vcpu));
return user_mode != 0;
}
static unsigned long kvm_get_guest_ip(void)
{
unsigned long ip = 0;
if (__this_cpu_read(current_vcpu))
ip = kvm_rip_read(__this_cpu_read(current_vcpu));
return ip;
}
static void kvm_handle_intel_pt_intr(void)
unsigned int kvm_guest_state(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
unsigned int state;
if (!vcpu)
return 0;
state = PERF_GUEST_ACTIVE;
if (static_call(kvm_x86_get_cpl)(vcpu))
state |= PERF_GUEST_USER;
return state;
}
static unsigned long kvm_guest_get_ip(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
if (WARN_ON_ONCE(!vcpu))
return 0;
return kvm_rip_read(vcpu);
}
static unsigned int kvm_handle_intel_pt_intr(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);
/* '0' on failure so that the !PT case can use a RET0 static call. */
if (!vcpu)
return 0;
kvm_make_request(KVM_REQ_PMI, vcpu);
__set_bit(MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI_BIT,
(unsigned long *)&vcpu->arch.pmu.global_status);
return 1;
}
static struct perf_guest_info_callbacks kvm_guest_cbs = {
.is_in_guest = kvm_is_in_guest,
.is_user_mode = kvm_is_user_mode,
.get_guest_ip = kvm_get_guest_ip,
.state = kvm_guest_state,
.get_ip = kvm_guest_get_ip,
.handle_intel_pt_intr = NULL,
};

32
arch/x86/xen/pmu.c
View File

@ -413,34 +413,29 @@ int pmu_apic_update(uint32_t val)
}
/* perf callbacks */
static int xen_is_in_guest(void)
static unsigned int xen_guest_state(void)
{
const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
unsigned int state = 0;
if (!xenpmu_data) {
pr_warn_once("%s: pmudata not initialized\n", __func__);
return 0;
return state;
}
if (!xen_initial_domain() || (xenpmu_data->domain_id >= DOMID_SELF))
return 0;
return state;
return 1;
}
state |= PERF_GUEST_ACTIVE;
static int xen_is_user_mode(void)
{
const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
if (!xenpmu_data) {
pr_warn_once("%s: pmudata not initialized\n", __func__);
return 0;
if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_PV) {
if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_USER)
state |= PERF_GUEST_USER;
} else if (xenpmu_data->pmu.r.regs.cpl & 3) {
state |= PERF_GUEST_USER;
}
if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_PV)
return (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_USER);
else
return !!(xenpmu_data->pmu.r.regs.cpl & 3);
return state;
}
static unsigned long xen_get_guest_ip(void)
@ -456,9 +451,8 @@ static unsigned long xen_get_guest_ip(void)
}
static struct perf_guest_info_callbacks xen_guest_cbs = {
.is_in_guest = xen_is_in_guest,
.is_user_mode = xen_is_user_mode,
.get_guest_ip = xen_get_guest_ip,
.state = xen_guest_state,
.get_ip = xen_get_guest_ip,
};
/* Convert registers from Xen's format to Linux' */

10
include/linux/perf_event.h
View File

@ -26,11 +26,13 @@
# include <asm/local64.h>
#endif
#define PERF_GUEST_ACTIVE 0x01
#define PERF_GUEST_USER 0x02
struct perf_guest_info_callbacks {
int (*is_in_guest)(void);
int (*is_user_mode)(void);
unsigned long (*get_guest_ip)(void);
void (*handle_intel_pt_intr)(void);
unsigned int (*state)(void);
unsigned long (*get_ip)(void);
unsigned int (*handle_intel_pt_intr)(void);
};
#ifdef CONFIG_HAVE_HW_BREAKPOINT