From patchwork Mon Dec 18 10:40:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Atish Kumar Patra X-Patchwork-Id: 13496540 Received: from mail-oo1-f50.google.com (mail-oo1-f50.google.com [209.85.161.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDA3114F74 for ; Mon, 18 Dec 2023 10:41:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="sB82Qz9j" Received: by mail-oo1-f50.google.com with SMTP id 006d021491bc7-590a2a963baso2079592eaf.2 for ; Mon, 18 Dec 2023 02:41:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1702896077; x=1703500877; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=BAExNJX/YhcccIuIFbir4pLgBR3qGdMXJeV+rbaaqC4=; b=sB82Qz9jn/1vXf4iFqaX9zthIM9P/nBvrrAvvXXwNIRSw+AbpaN8yo8cd1tN7VBVVI IH8rRyuX11TC3hgVUc9oPFwkaWrZboMF4w8yv8VJSndgHOsNiS6ipBIh0KGYJ5hwT5zq Tby6S+s5AJpUMpsqMID6vOtMDo8ddkO6t+Qvf5RHmHGiZGM1YMOKQg7qrzcrqH9PmcS8 JMSGIvDiXhpXbHPN8RKGaQGoaCByyXMMBCvHCUq8W2a4R1qSSGcweJQmmgyTPf4TBTHN so7pghIxgm90hz8+4JA9UQ4zfGBce/nZaDD0AjrWattLIQ0wcnkAGXlEAyXiKGvOI2ss QUxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702896077; x=1703500877; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=BAExNJX/YhcccIuIFbir4pLgBR3qGdMXJeV+rbaaqC4=; b=fQuJHx84GoblvcZd9j8aqzmWRwPS/82SWzr7bmFZHAfoKWAqovaiCQ0JJ/oAr3AwID I7RDlPRPLZ9LJmjtWheWJMQTlv0BSvy+X1h15h1tO5CqRYnis8kEhHlWQU1+EUmU50TN TARDNYc72+qVcdYoQ5CJYmj5qqM1Aj0d5m5IKxSQADVjcd2/fNwUoJk4Oh3XdFkm0Ny9 0Ao2jWEd6wgyF7eHyIFDiEH4cBtOAHs2lBdk0tyU+7++4Q10r68vLplhZQ/OeTqDxprp 9SBnMqqUEUIvl1ZZ3/hFvKLmjvu1TrYFk7WSL6jYhe3RBSSCErevJUyDBLz9oxEShKGL I5xA== X-Gm-Message-State: AOJu0YyVP8ZLvRm/38iVfaV9VJ8mHUD59OaJ1srBcL0wnY55mrS610u6 CioWwEFL5EDeQ+TzYTjM5GslWw== X-Google-Smtp-Source: AGHT+IGDKrqtxtZbZ8QYlYUWKhg2x8cwPY4Y/RPNofta2lY7xmBPtEBlNRLdIG8f3YPqu7ksXNPzqA== X-Received: by 2002:a05:6820:607:b0:590:2df8:1bc7 with SMTP id e7-20020a056820060700b005902df81bc7mr12054984oow.1.1702896076749; Mon, 18 Dec 2023 02:41:16 -0800 (PST) Received: from atishp.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id 185-20020a4a1ac2000000b005907ad9f302sm574970oof.37.2023.12.18.02.41.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Dec 2023 02:41:16 -0800 (PST) From: Atish Patra To: linux-kernel@vger.kernel.org Cc: Atish Patra , Albert Ou , Alexandre Ghiti , Andrew Jones , Anup Patel , Atish Patra , Conor Dooley , Guo Ren , Icenowy Zheng , kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Rutland , Palmer Dabbelt , Paul Walmsley , Will Deacon Subject: [v1 00/10] RISC-V SBI v2.0 PMU improvements and Perf sampling in KVM guest Date: Mon, 18 Dec 2023 02:40:57 -0800 Message-Id: <20231218104107.2976925-1-atishp@rivosinc.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This series implements SBI PMU improvements done in SBI v2.0[1] i.e. PMU snapshot and fw_read_hi() functions. SBI v2.0 introduced PMU snapshot feature which allows the SBI implementation to provide counter information (i.e. values/overlfow status) via a shared memory between the SBI implementation and supervisor OS. This allows to minimize the number of traps in when perf being used inside a kvm guest as it relies on SBI PMU + trap/emulation of the counters. The current set of ratified RISC-V specification also doesn't allow scountovf to be trap/emulated by the hypervisor. The SBI PMU snapshot bridges the gap in ISA as well and enables perf sampling in the guest. However, LCOFI in the guest only works via IRQ filtering in AIA specification. That's why, AIA has to be enabled in the hardware (at least the Ssaia extension) in order to use the sampling support in the perf. Here are the patch wise implementation details. PATCH 1,6,7 : Generic cleanups/improvements. PATCH 2,3,10 : FW_READ_HI function implementation PATCH 4-5: Add PMU snapshot feature in sbi pmu driver PATCH 6-7: KVM implementation for snapshot and sampling in kvm guests The series is based on v6.70-rc3 and is available at: https://github.com/atishp04/linux/tree/kvm_pmu_snapshot_v1 The kvmtool patch is also available at: https://github.com/atishp04/kvmtool/tree/sscofpmf It also requires Ssaia ISA extension to be present in the hardware in order to get perf sampling support in the guest. In Qemu virt machine, it can be done by the following config. ``` -cpu rv64,sscofpmf=true,x-ssaia=true ``` There is no other dependancies on AIA apart from that. Thus, Ssaia must be disabled for the guest if AIA patches are not available. Here is the example command. ``` ./lkvm-static run -m 256 -c2 --console serial -p "console=ttyS0 earlycon" --disable-ssaia -k ./Image --debug ``` The series has been tested only in Qemu. Here is the snippet of the perf running inside a kvm guest. =================================================== # perf record -e cycles -e instructions perf bench sched messaging -g 5 ... # Running 'sched/messaging' benchmark: ... [ 45.928723] perf_duration_warn: 2 callbacks suppressed [ 45.929000] perf: interrupt took too long (484426 > 483186), lowering kernel.perf_event_max_sample_rate to 250 # 20 sender and receiver processes per group # 5 groups == 200 processes run Total time: 14.220 [sec] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.117 MB perf.data (1942 samples) ] # perf report --stdio # To display the perf.data header info, please use --header/--header-only optio> # # # Total Lost Samples: 0 # # Samples: 943 of event 'cycles' # Event count (approx.): 5128976844 # # Overhead Command Shared Object Symbol > # ........ ............... ........................... .....................> # 7.59% sched-messaging [kernel.kallsyms] [k] memcpy 5.48% sched-messaging [kernel.kallsyms] [k] percpu_counter_ad> 5.24% sched-messaging [kernel.kallsyms] [k] __sbi_rfence_v02_> 4.00% sched-messaging [kernel.kallsyms] [k] _raw_spin_unlock_> 3.79% sched-messaging [kernel.kallsyms] [k] set_pte_range 3.72% sched-messaging [kernel.kallsyms] [k] next_uptodate_fol> 3.46% sched-messaging [kernel.kallsyms] [k] filemap_map_pages 3.31% sched-messaging [kernel.kallsyms] [k] handle_mm_fault 3.20% sched-messaging [kernel.kallsyms] [k] finish_task_switc> 3.16% sched-messaging [kernel.kallsyms] [k] clear_page 3.03% sched-messaging [kernel.kallsyms] [k] mtree_range_walk 2.42% sched-messaging [kernel.kallsyms] [k] flush_icache_pte =================================================== [1] https://github.com/riscv-non-isa/riscv-sbi-doc Changes from RFC->v1: 1. Addressed all the comments on RFC series. 2. Removed PATCH2 and merged into later patches. 3. Added 2 more patches for minor fixes. 4. Fixed KVM boot issue without Ssaia and made sscofpmf in guest dependant on Ssaia in the host. Atish Patra (10): RISC-V: Fix the typo in Scountovf CSR name RISC-V: Add FIRMWARE_READ_HI definition drivers/perf: riscv: Read upper bits of a firmware counter RISC-V: Add SBI PMU snapshot definitions drivers/perf: riscv: Implement SBI PMU snapshot function RISC-V: KVM: No need to update the counter value during reset RISC-V: KVM: No need to exit to the user space if perf event failed RISC-V: KVM: Implement SBI PMU Snapshot feature RISC-V: KVM: Add perf sampling support for guests RISC-V: KVM: Support 64 bit firmware counters on RV32 arch/riscv/include/asm/csr.h | 5 +- arch/riscv/include/asm/errata_list.h | 2 +- arch/riscv/include/asm/kvm_vcpu_pmu.h | 14 +- arch/riscv/include/asm/sbi.h | 12 ++ arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kvm/aia.c | 5 + arch/riscv/kvm/main.c | 1 + arch/riscv/kvm/vcpu.c | 8 +- arch/riscv/kvm/vcpu_onereg.c | 9 +- arch/riscv/kvm/vcpu_pmu.c | 246 ++++++++++++++++++++++++-- arch/riscv/kvm/vcpu_sbi_pmu.c | 15 +- drivers/perf/riscv_pmu.c | 1 + drivers/perf/riscv_pmu_sbi.c | 230 ++++++++++++++++++++++-- include/linux/perf/riscv_pmu.h | 6 + 14 files changed, 510 insertions(+), 45 deletions(-) --- 2.34.1