* [PATCH v3 1/2] riscv: perf: add guest vs host distinction
2024-09-12 8:00 [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side zhouquan
@ 2024-09-12 8:00 ` zhouquan
2024-09-16 12:38 ` Andrew Jones
2024-09-12 8:00 ` [PATCH v3 2/2] riscv: KVM: add basic support for host vs guest profiling zhouquan
2024-10-05 11:06 ` [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side Anup Patel
2 siblings, 1 reply; 6+ messages in thread
From: zhouquan @ 2024-09-12 8:00 UTC (permalink / raw)
To: anup, ajones, atishp, paul.walmsley, palmer, aou, mark.rutland,
alexander.shishkin, jolsa
Cc: linux-kernel, linux-riscv, kvm, kvm-riscv, linux-perf-users,
Quan Zhou
From: Quan Zhou <zhouquan@iscas.ac.cn>
Introduce basic guest support in perf, enabling it to distinguish
between PMU interrupts in the host or guest, and collect
fundamental information.
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
---
arch/riscv/include/asm/perf_event.h | 7 ++++++
arch/riscv/kernel/perf_callchain.c | 38 +++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
diff --git a/arch/riscv/include/asm/perf_event.h b/arch/riscv/include/asm/perf_event.h
index 665bbc9b2f84..c2b73c3aefe4 100644
--- a/arch/riscv/include/asm/perf_event.h
+++ b/arch/riscv/include/asm/perf_event.h
@@ -8,13 +8,20 @@
#ifndef _ASM_RISCV_PERF_EVENT_H
#define _ASM_RISCV_PERF_EVENT_H
+#ifdef CONFIG_PERF_EVENTS
#include <linux/perf_event.h>
#define perf_arch_bpf_user_pt_regs(regs) (struct user_regs_struct *)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)
+
#define perf_arch_fetch_caller_regs(regs, __ip) { \
(regs)->epc = (__ip); \
(regs)->s0 = (unsigned long) __builtin_frame_address(0); \
(regs)->sp = current_stack_pointer; \
(regs)->status = SR_PP; \
}
+#endif
+
#endif /* _ASM_RISCV_PERF_EVENT_H */
diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
index 3348a61de7d9..d68271ac7434 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c
@@ -58,6 +58,11 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
{
unsigned long fp = 0;
+ if (perf_guest_state()) {
+ /* TODO: We don't support guest os callchain now */
+ return;
+ }
+
fp = regs->s0;
perf_callchain_store(entry, regs->epc);
@@ -74,5 +79,38 @@ static bool fill_callchain(void *entry, unsigned long pc)
void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
struct pt_regs *regs)
{
+ if (perf_guest_state()) {
+ /* TODO: We don't support guest os callchain now */
+ return;
+ }
+
walk_stackframe(NULL, regs, fill_callchain, entry);
}
+
+unsigned long perf_instruction_pointer(struct pt_regs *regs)
+{
+ if (perf_guest_state())
+ return perf_guest_get_ip();
+
+ return instruction_pointer(regs);
+}
+
+unsigned long perf_misc_flags(struct pt_regs *regs)
+{
+ unsigned int guest_state = perf_guest_state();
+ unsigned long misc = 0;
+
+ if (guest_state) {
+ if (guest_state & PERF_GUEST_USER)
+ misc |= PERF_RECORD_MISC_GUEST_USER;
+ else
+ misc |= PERF_RECORD_MISC_GUEST_KERNEL;
+ } else {
+ if (user_mode(regs))
+ misc |= PERF_RECORD_MISC_USER;
+ else
+ misc |= PERF_RECORD_MISC_KERNEL;
+ }
+
+ return misc;
+}
--
2.34.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3 1/2] riscv: perf: add guest vs host distinction
2024-09-12 8:00 ` [PATCH v3 1/2] riscv: perf: add guest vs host distinction zhouquan
@ 2024-09-16 12:38 ` Andrew Jones
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Jones @ 2024-09-16 12:38 UTC (permalink / raw)
To: zhouquan
Cc: anup, atishp, paul.walmsley, palmer, aou, mark.rutland,
alexander.shishkin, jolsa, linux-kernel, linux-riscv, kvm,
kvm-riscv, linux-perf-users
On Thu, Sep 12, 2024 at 04:00:29PM GMT, zhouquan@iscas.ac.cn wrote:
> From: Quan Zhou <zhouquan@iscas.ac.cn>
>
> Introduce basic guest support in perf, enabling it to distinguish
> between PMU interrupts in the host or guest, and collect
> fundamental information.
>
> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
> ---
> arch/riscv/include/asm/perf_event.h | 7 ++++++
> arch/riscv/kernel/perf_callchain.c | 38 +++++++++++++++++++++++++++++
> 2 files changed, 45 insertions(+)
>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v3 2/2] riscv: KVM: add basic support for host vs guest profiling
2024-09-12 8:00 [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side zhouquan
2024-09-12 8:00 ` [PATCH v3 1/2] riscv: perf: add guest vs host distinction zhouquan
@ 2024-09-12 8:00 ` zhouquan
2024-09-16 12:41 ` Andrew Jones
2024-10-05 11:06 ` [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side Anup Patel
2 siblings, 1 reply; 6+ messages in thread
From: zhouquan @ 2024-09-12 8:00 UTC (permalink / raw)
To: anup, ajones, atishp, paul.walmsley, palmer, aou, mark.rutland,
alexander.shishkin, jolsa
Cc: linux-kernel, linux-riscv, kvm, kvm-riscv, linux-perf-users,
Quan Zhou
From: Quan Zhou <zhouquan@iscas.ac.cn>
For the information collected on the host side, we need to
identify which data originates from the guest and record
these events separately, this can be achieved by having
KVM register perf callbacks.
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
---
arch/riscv/include/asm/kvm_host.h | 10 ++++++++++
arch/riscv/kvm/Kconfig | 1 +
arch/riscv/kvm/main.c | 12 ++++++++++--
arch/riscv/kvm/vcpu.c | 7 +++++++
4 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 2e2254fd2a2a..35eab6e0f4ae 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -286,6 +286,16 @@ struct kvm_vcpu_arch {
} sta;
};
+/*
+ * Returns true if a Performance Monitoring Interrupt (PMI), a.k.a. perf event,
+ * arrived in guest context. For riscv, any event that arrives while a vCPU is
+ * loaded is considered to be "in guest".
+ */
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+ return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
+}
+
static inline void kvm_arch_sync_events(struct kvm *kvm) {}
#define KVM_RISCV_GSTAGE_TLB_MIN_ORDER 12
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 26d1727f0550..0c3cbb0915ff 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -32,6 +32,7 @@ config KVM
select KVM_XFER_TO_GUEST_WORK
select KVM_GENERIC_MMU_NOTIFIER
select SCHED_INFO
+ select GUEST_PERF_EVENTS if PERF_EVENTS
help
Support hosting virtualized guest machines.
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index bab2ec34cd87..734b48d8f6dd 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -51,6 +51,12 @@ void kvm_arch_hardware_disable(void)
csr_write(CSR_HIDELEG, 0);
}
+static void kvm_riscv_teardown(void)
+{
+ kvm_riscv_aia_exit();
+ kvm_unregister_perf_callbacks();
+}
+
static int __init riscv_kvm_init(void)
{
int rc;
@@ -105,9 +111,11 @@ static int __init riscv_kvm_init(void)
kvm_info("AIA available with %d guest external interrupts\n",
kvm_riscv_aia_nr_hgei);
+ kvm_register_perf_callbacks(NULL);
+
rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
if (rc) {
- kvm_riscv_aia_exit();
+ kvm_riscv_teardown();
return rc;
}
@@ -117,7 +125,7 @@ module_init(riscv_kvm_init);
static void __exit riscv_kvm_exit(void)
{
- kvm_riscv_aia_exit();
+ kvm_riscv_teardown();
kvm_exit();
}
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 8d7d381737ee..e8ffb3456898 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -226,6 +226,13 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
}
+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.guest_context.sepc;
+}
+#endif
+
vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
{
return VM_FAULT_SIGBUS;
--
2.34.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v3 2/2] riscv: KVM: add basic support for host vs guest profiling
2024-09-12 8:00 ` [PATCH v3 2/2] riscv: KVM: add basic support for host vs guest profiling zhouquan
@ 2024-09-16 12:41 ` Andrew Jones
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Jones @ 2024-09-16 12:41 UTC (permalink / raw)
To: zhouquan
Cc: anup, atishp, paul.walmsley, palmer, aou, mark.rutland,
alexander.shishkin, jolsa, linux-kernel, linux-riscv, kvm,
kvm-riscv, linux-perf-users
On Thu, Sep 12, 2024 at 04:00:38PM GMT, zhouquan@iscas.ac.cn wrote:
> From: Quan Zhou <zhouquan@iscas.ac.cn>
>
> For the information collected on the host side, we need to
> identify which data originates from the guest and record
> these events separately, this can be achieved by having
> KVM register perf callbacks.
>
> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
> ---
> arch/riscv/include/asm/kvm_host.h | 10 ++++++++++
> arch/riscv/kvm/Kconfig | 1 +
> arch/riscv/kvm/main.c | 12 ++++++++++--
> arch/riscv/kvm/vcpu.c | 7 +++++++
> 4 files changed, 28 insertions(+), 2 deletions(-)
>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side
2024-09-12 8:00 [PATCH v3 0/2] riscv: Add perf support to collect KVM guest statistics from host side zhouquan
2024-09-12 8:00 ` [PATCH v3 1/2] riscv: perf: add guest vs host distinction zhouquan
2024-09-12 8:00 ` [PATCH v3 2/2] riscv: KVM: add basic support for host vs guest profiling zhouquan
@ 2024-10-05 11:06 ` Anup Patel
2 siblings, 0 replies; 6+ messages in thread
From: Anup Patel @ 2024-10-05 11:06 UTC (permalink / raw)
To: zhouquan
Cc: ajones, atishp, paul.walmsley, palmer, aou, mark.rutland,
alexander.shishkin, jolsa, linux-kernel, linux-riscv, kvm,
kvm-riscv, linux-perf-users
On Thu, Sep 12, 2024 at 1:30 PM <zhouquan@iscas.ac.cn> wrote:
>
> From: Quan Zhou <zhouquan@iscas.ac.cn>
>
> Add basic guest support to RISC-V perf, enabling it to distinguish
> whether PMU interrupts occur in the host or the guest, and then
> collect some basic guest information from the host side
> (guest os callchain is not supported for now).
>
> Based on the x86/arm implementation, tested with kvm-riscv.
> test env:
> - host: qemu-9.0.0
> - guest: qemu-9.0.0 --enable-kvm (only start one guest and run top)
>
> -----------------------------------------
> 1) perf kvm top
> ./perf kvm --host --guest \
> --guestkallsyms=/root/repo/shared/kallsyms \
> --guestmodules=/root/repo/shared/modules top
>
> PerfTop: 41 irqs/sec kernel:97.6% us: 0.0% guest kernel: 0.0% guest us: 0.0% exact: 0.0% [250Hz cycles:P], (all, 4 CPUs)
> -------------------------------------------------------------------------------
>
> 64.57% [kernel] [k] default_idle_call
> 3.12% [kernel] [k] _raw_spin_unlock_irqrestore
> 3.03% [guest.kernel] [g] mem_serial_out
> 2.61% [kernel] [k] handle_softirqs
> 2.32% [kernel] [k] do_trap_ecall_u
> 1.71% [kernel] [k] _raw_spin_unlock_irq
> 1.26% [guest.kernel] [g] do_raw_spin_lock
> 1.25% [kernel] [k] finish_task_switch.isra.0
> 1.16% [kernel] [k] do_idle
> 0.77% libc.so.6 [.] ioctl
> 0.76% [kernel] [k] queue_work_on
> 0.69% [kernel] [k] __local_bh_enable_ip
> 0.67% [guest.kernel] [g] __noinstr_text_start
> 0.64% [guest.kernel] [g] mem_serial_in
> 0.41% libc.so.6 [.] pthread_sigmask
> 0.39% [kernel] [k] mem_cgroup_uncharge_skmem
> 0.39% [kernel] [k] __might_resched
> 0.39% [guest.kernel] [g] _nohz_idle_balance.isra.0
> 0.37% [kernel] [k] sched_balance_update_blocked_averages
> 0.34% [kernel] [k] sched_balance_rq
>
> 2) perf kvm record
> ./perf kvm --host --guest \
> --guestkallsyms=/root/repo/shared/kallsyms \
> --guestmodules=/root/repo/shared/modules record -a sleep 60
>
> [ perf record: Woken up 3 times to write data ]
> [ perf record: Captured and wrote 1.292 MB perf.data.kvm (17990 samples) ]
>
> 3) perf kvm report (the data shown here is not complete)
> ./perf kvm --host --guest \
> --guestkallsyms=/root/repo/shared/kallsyms \
> --guestmodules=/root/repo/shared/modules report -i perf.data.kvm
>
> # Total Lost Samples: 0
> #
> # Samples: 17K of event 'cycles:P'
> # Event count (approx.): 269968947184
> #
> # Overhead Command Shared Object Symbol
> # ........ ............... ....................... ..............................................
> #
> 61.86% swapper [kernel.kallsyms] [k] default_idle_call
> 2.93% :6463 [guest.kernel.kallsyms] [g] do_raw_spin_lock
> 2.82% :6462 [guest.kernel.kallsyms] [g] mem_serial_out
> 2.11% sshd [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
> 1.78% :6462 [guest.kernel.kallsyms] [g] do_raw_spin_lock
> 1.37% swapper [kernel.kallsyms] [k] handle_softirqs
> 1.36% swapper [kernel.kallsyms] [k] do_idle
> 1.21% sshd [kernel.kallsyms] [k] do_trap_ecall_u
> 1.21% sshd [kernel.kallsyms] [k] _raw_spin_unlock_irq
> 1.11% qemu-system-ris [kernel.kallsyms] [k] do_trap_ecall_u
> 0.93% qemu-system-ris libc.so.6 [.] ioctl
> 0.89% sshd [kernel.kallsyms] [k] __local_bh_enable_ip
> 0.77% qemu-system-ris [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
> 0.68% qemu-system-ris [kernel.kallsyms] [k] queue_work_on
> 0.65% sshd [kernel.kallsyms] [k] handle_softirqs
> 0.44% :6462 [guest.kernel.kallsyms] [g] mem_serial_in
> 0.42% sshd libc.so.6 [.] pthread_sigmask
> 0.34% :6462 [guest.kernel.kallsyms] [g] serial8250_tx_chars
> 0.30% swapper [kernel.kallsyms] [k] finish_task_switch.isra.0
> 0.29% swapper [kernel.kallsyms] [k] sched_balance_rq
> 0.29% sshd [kernel.kallsyms] [k] __might_resched
> 0.26% swapper [kernel.kallsyms] [k] tick_nohz_idle_exit
> 0.26% swapper [kernel.kallsyms] [k] sched_balance_update_blocked_averages
> 0.26% swapper [kernel.kallsyms] [k] _nohz_idle_balance.isra.0
> 0.24% qemu-system-ris [kernel.kallsyms] [k] finish_task_switch.isra.0
> 0.23% :6462 [guest.kernel.kallsyms] [g] __noinstr_text_start
>
> ---
> Change since v2:
> - Rebased on v6.11-rc7
> - Keep the misc type consistent with other architectures
> as `unsigned long` (Andrew)
> - Add the same comment for `kvm_arch_pmi_in_guest`
> as in arm64. (Andrew)
>
> Change since v1:
> - Rebased on v6.11-rc3
> - Fix incorrect misc type (Andrew)
>
> ---
> v1 link:
> https://lore.kernel.org/all/cover.1721271251.git.zhouquan@iscas.ac.cn/
> v2 link:
> https://lore.kernel.org/all/cover.1723518282.git.zhouquan@iscas.ac.cn/
>
> Quan Zhou (2):
> riscv: perf: add guest vs host distinction
> riscv: KVM: add basic support for host vs guest profiling
Please rebase this series upon Linux-6.12-rcX and send another version.
Regards,
Anup
>
> arch/riscv/include/asm/kvm_host.h | 10 ++++++++
> arch/riscv/include/asm/perf_event.h | 7 ++++++
> arch/riscv/kernel/perf_callchain.c | 38 +++++++++++++++++++++++++++++
> arch/riscv/kvm/Kconfig | 1 +
> arch/riscv/kvm/main.c | 12 +++++++--
> arch/riscv/kvm/vcpu.c | 7 ++++++
> 6 files changed, 73 insertions(+), 2 deletions(-)
>
>
> base-commit: da3ea35007d0af457a0afc87e84fddaebc4e0b63
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread