From patchwork Wed Jan 10 23:13:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Atish Kumar Patra X-Patchwork-Id: 13516663 Received: from mail-io1-f43.google.com (mail-io1-f43.google.com [209.85.166.43]) (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 EC67754BDE for ; Wed, 10 Jan 2024 23:14:50 +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="xxJISzGa" Received: by mail-io1-f43.google.com with SMTP id ca18e2360f4ac-7bc32b04d16so199260939f.0 for ; Wed, 10 Jan 2024 15:14:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1704928490; x=1705533290; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=4ymgmumoudNB/wN3zowFkODrzcqTcd6665yl2L5pnQU=; b=xxJISzGaG/bfqQ9rl2OTJ5iHAU4HCJevEIL8Z4cMPFYYRIsy5uuKIpDqt2BmNOPgRx ruPSXaV1m037ctx9w8CuG9BZP736yVLwWTsq3qCqKy2YK5kpP1aQn0HxxFQmCj9vWdC+ 1b77z0kPtyQr0hZ1a837xkkCdoWk7hjqb5cM7pnhRVtCXpQ2X8RR8xnpyrJwAG7oqpoU 1AVYNTASEfu9V6GxFUmVUrPxmjy+0q+kBCm8Sa9jPJLa6N6VtGa9IPqYWhobABhmbP1C aKIj5eE2q8tcj1v45qEHQ4c8mN1fjpNQmqIqYqAKXF1yxXUQdLITfPUclMxsbz8h17KO RClQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704928490; x=1705533290; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4ymgmumoudNB/wN3zowFkODrzcqTcd6665yl2L5pnQU=; b=OP312itOiy7igY2ApR1xPfFxz75ze/oPqFA3LNxoSbZ7Kpx4spzSdrZg8wzgzDggyW otgScg/IqK/EmWC1fsmjSOd/Cr5gTrolZXz0s66Cs4Y4iEyVfUwme2JSEiifRrfgyiaq 77Tu/XbK/4pehm1sr10LXvEjRb0/EHcl2qiyjm0WbTNuFb8L9l6tr1mqbKIEGjlGH4va WDb2t0UffoJPtk4GqQbhEwtP/0bY8oQoV8TkVM0t7dKw/0Yuo0Z7izTGhwu4AiTivgiS cqnrelRDA+NbcMvEDqQgUFybLwB8vcQ670XVkL80NjBWJCVugW+r4AGu7Ckwve5JQeOi GyBw== X-Gm-Message-State: AOJu0Yy5koY2BeXqNr2bJhj2td0TO0AHnMjtFxTo0dgXRZ65eXTlgzRt CRXFauAXePYJ+v/O/vCEzzeiCpKYzk6EAg== X-Google-Smtp-Source: AGHT+IEBrJvcmp0z9cRbrl/cYdMmAuqNUhkHuP1bqFpvH7zFsUr66dYYdNFD9nWIMUnU4ZDfRyAw3w== X-Received: by 2002:a5d:9917:0:b0:7bc:d40:6064 with SMTP id x23-20020a5d9917000000b007bc0d406064mr359544iol.28.1704928490166; Wed, 10 Jan 2024 15:14:50 -0800 (PST) Received: from atishp.ba.rivosinc.com ([64.71.180.162]) by smtp.gmail.com with ESMTPSA id co13-20020a0566383e0d00b0046e3b925818sm1185503jab.37.2024.01.10.15.14.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jan 2024 15:14:49 -0800 (PST) From: Atish Patra To: linux-kernel@vger.kernel.org Cc: Atish Patra , Anup Patel , Alexandre Ghiti , Andrew Jones , 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 , Vladimir Isaev Subject: [v3 08/10] RISC-V: KVM: Implement SBI PMU Snapshot feature Date: Wed, 10 Jan 2024 15:13:57 -0800 Message-Id: <20240110231359.1239367-9-atishp@rivosinc.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240110231359.1239367-1-atishp@rivosinc.com> References: <20240110231359.1239367-1-atishp@rivosinc.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 PMU Snapshot function allows to minimize the number of traps when the guest access configures/access the hpmcounters. If the snapshot feature is enabled, the hypervisor updates the shared memory with counter data and state of overflown counters. The guest can just read the shared memory instead of trap & emulate done by the hypervisor. This patch doesn't implement the counter overflow yet. Reviewed-by: Anup Patel Signed-off-by: Atish Patra --- arch/riscv/include/asm/kvm_vcpu_pmu.h | 7 ++ arch/riscv/kvm/vcpu_pmu.c | 119 +++++++++++++++++++++++++- arch/riscv/kvm/vcpu_sbi_pmu.c | 3 + 3 files changed, 127 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/kvm_vcpu_pmu.h b/arch/riscv/include/asm/kvm_vcpu_pmu.h index 395518a1664e..586bab84be35 100644 --- a/arch/riscv/include/asm/kvm_vcpu_pmu.h +++ b/arch/riscv/include/asm/kvm_vcpu_pmu.h @@ -50,6 +50,10 @@ struct kvm_pmu { bool init_done; /* Bit map of all the virtual counter used */ DECLARE_BITMAP(pmc_in_use, RISCV_KVM_MAX_COUNTERS); + /* The address of the counter snapshot area (guest physical address) */ + gpa_t snapshot_addr; + /* The actual data of the snapshot */ + struct riscv_pmu_snapshot_data *sdata; }; #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu_context) @@ -85,6 +89,9 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba int kvm_riscv_vcpu_pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx, struct kvm_vcpu_sbi_return *retdata); void kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu); +int kvm_riscv_vcpu_pmu_setup_snapshot(struct kvm_vcpu *vcpu, unsigned long saddr_low, + unsigned long saddr_high, unsigned long flags, + struct kvm_vcpu_sbi_return *retdata); void kvm_riscv_vcpu_pmu_deinit(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_pmu_reset(struct kvm_vcpu *vcpu); diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index 29bf4ca798cb..b3112c23ad33 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -311,6 +311,81 @@ int kvm_riscv_vcpu_pmu_read_hpm(struct kvm_vcpu *vcpu, unsigned int csr_num, return ret; } +static void kvm_pmu_clear_snapshot_area(struct kvm_vcpu *vcpu) +{ + struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu); + int snapshot_area_size = sizeof(struct riscv_pmu_snapshot_data); + + if (kvpmu->sdata) { + memset(kvpmu->sdata, 0, snapshot_area_size); + if (kvpmu->snapshot_addr != INVALID_GPA) + kvm_vcpu_write_guest(vcpu, kvpmu->snapshot_addr, + kvpmu->sdata, snapshot_area_size); + kfree(kvpmu->sdata); + kvpmu->sdata = NULL; + } + kvpmu->snapshot_addr = INVALID_GPA; +} + +int kvm_riscv_vcpu_pmu_setup_snapshot(struct kvm_vcpu *vcpu, unsigned long saddr_low, + unsigned long saddr_high, unsigned long flags, + struct kvm_vcpu_sbi_return *retdata) +{ + struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu); + int snapshot_area_size = sizeof(struct riscv_pmu_snapshot_data); + int sbiret = 0; + gpa_t saddr; + unsigned long hva; + bool writable; + + if (!kvpmu) { + sbiret = SBI_ERR_INVALID_PARAM; + goto out; + } + + if (saddr_low == -1 && saddr_high == -1) { + kvm_pmu_clear_snapshot_area(vcpu); + return 0; + } + + saddr = saddr_low; + + if (saddr_high != 0) { + if (IS_ENABLED(CONFIG_32BIT)) + saddr |= ((gpa_t)saddr << 32); + else + sbiret = SBI_ERR_INVALID_ADDRESS; + goto out; + } + + if (kvm_is_error_gpa(vcpu->kvm, saddr)) { + sbiret = SBI_ERR_INVALID_PARAM; + goto out; + } + + hva = kvm_vcpu_gfn_to_hva_prot(vcpu, saddr >> PAGE_SHIFT, &writable); + if (kvm_is_error_hva(hva) || !writable) { + sbiret = SBI_ERR_INVALID_ADDRESS; + goto out; + } + + kvpmu->snapshot_addr = saddr; + kvpmu->sdata = kzalloc(snapshot_area_size, GFP_ATOMIC); + if (!kvpmu->sdata) + return -ENOMEM; + + if (kvm_vcpu_write_guest(vcpu, saddr, kvpmu->sdata, snapshot_area_size)) { + kfree(kvpmu->sdata); + kvpmu->snapshot_addr = INVALID_GPA; + sbiret = SBI_ERR_FAILURE; + } + +out: + retdata->err_val = sbiret; + + return 0; +} + int kvm_riscv_vcpu_pmu_num_ctrs(struct kvm_vcpu *vcpu, struct kvm_vcpu_sbi_return *retdata) { @@ -344,20 +419,32 @@ int kvm_riscv_vcpu_pmu_ctr_start(struct kvm_vcpu *vcpu, unsigned long ctr_base, int i, pmc_index, sbiret = 0; struct kvm_pmc *pmc; int fevent_code; + bool snap_flag_set = flags & SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT; if (kvm_pmu_validate_counter_mask(kvpmu, ctr_base, ctr_mask) < 0) { sbiret = SBI_ERR_INVALID_PARAM; goto out; } + if (snap_flag_set && kvpmu->snapshot_addr == INVALID_GPA) { + sbiret = SBI_ERR_NO_SHMEM; + goto out; + } + /* Start the counters that have been configured and requested by the guest */ for_each_set_bit(i, &ctr_mask, RISCV_MAX_COUNTERS) { pmc_index = i + ctr_base; if (!test_bit(pmc_index, kvpmu->pmc_in_use)) continue; pmc = &kvpmu->pmc[pmc_index]; - if (flags & SBI_PMU_START_FLAG_SET_INIT_VALUE) + if (flags & SBI_PMU_START_FLAG_SET_INIT_VALUE) { pmc->counter_val = ival; + } else if (snap_flag_set) { + kvm_vcpu_read_guest(vcpu, kvpmu->snapshot_addr, kvpmu->sdata, + sizeof(struct riscv_pmu_snapshot_data)); + pmc->counter_val = kvpmu->sdata->ctr_values[pmc_index]; + } + if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) { fevent_code = get_event_code(pmc->event_idx); if (fevent_code >= SBI_PMU_FW_MAX) { @@ -398,14 +485,21 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base, { struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu); int i, pmc_index, sbiret = 0; + u64 enabled, running; struct kvm_pmc *pmc; int fevent_code; + bool snap_flag_set = flags & SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT; - if (kvm_pmu_validate_counter_mask(kvpmu, ctr_base, ctr_mask) < 0) { + if ((kvm_pmu_validate_counter_mask(kvpmu, ctr_base, ctr_mask) < 0)) { sbiret = SBI_ERR_INVALID_PARAM; goto out; } + if (snap_flag_set && kvpmu->snapshot_addr == INVALID_GPA) { + sbiret = SBI_ERR_NO_SHMEM; + goto out; + } + /* Stop the counters that have been configured and requested by the guest */ for_each_set_bit(i, &ctr_mask, RISCV_MAX_COUNTERS) { pmc_index = i + ctr_base; @@ -438,9 +532,28 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base, } else { sbiret = SBI_ERR_INVALID_PARAM; } + + if (snap_flag_set && !sbiret) { + if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) + pmc->counter_val = kvpmu->fw_event[fevent_code].value; + else if (pmc->perf_event) + pmc->counter_val += perf_event_read_value(pmc->perf_event, + &enabled, &running); + /* TODO: Add counter overflow support when sscofpmf support is added */ + kvpmu->sdata->ctr_values[i] = pmc->counter_val; + kvm_vcpu_write_guest(vcpu, kvpmu->snapshot_addr, kvpmu->sdata, + sizeof(struct riscv_pmu_snapshot_data)); + } + if (flags & SBI_PMU_STOP_FLAG_RESET) { pmc->event_idx = SBI_PMU_EVENT_IDX_INVALID; clear_bit(pmc_index, kvpmu->pmc_in_use); + if (snap_flag_set) { + /* Clear the snapshot area for the upcoming deletion event */ + kvpmu->sdata->ctr_values[i] = 0; + kvm_vcpu_write_guest(vcpu, kvpmu->snapshot_addr, kvpmu->sdata, + sizeof(struct riscv_pmu_snapshot_data)); + } } } @@ -566,6 +679,7 @@ void kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu) kvpmu->num_hw_ctrs = num_hw_ctrs + 1; kvpmu->num_fw_ctrs = SBI_PMU_FW_MAX; memset(&kvpmu->fw_event, 0, SBI_PMU_FW_MAX * sizeof(struct kvm_fw_event)); + kvpmu->snapshot_addr = INVALID_GPA; if (kvpmu->num_hw_ctrs > RISCV_KVM_MAX_HW_CTRS) { pr_warn_once("Limiting the hardware counters to 32 as specified by the ISA"); @@ -625,6 +739,7 @@ void kvm_riscv_vcpu_pmu_deinit(struct kvm_vcpu *vcpu) } bitmap_zero(kvpmu->pmc_in_use, RISCV_MAX_COUNTERS); memset(&kvpmu->fw_event, 0, SBI_PMU_FW_MAX * sizeof(struct kvm_fw_event)); + kvm_pmu_clear_snapshot_area(vcpu); } void kvm_riscv_vcpu_pmu_reset(struct kvm_vcpu *vcpu) diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c index b70179e9e875..9f61136e4bb1 100644 --- a/arch/riscv/kvm/vcpu_sbi_pmu.c +++ b/arch/riscv/kvm/vcpu_sbi_pmu.c @@ -64,6 +64,9 @@ static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run, case SBI_EXT_PMU_COUNTER_FW_READ: ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata); break; + case SBI_EXT_PMU_SNAPSHOT_SET_SHMEM: + ret = kvm_riscv_vcpu_pmu_setup_snapshot(vcpu, cp->a0, cp->a1, cp->a2, retdata); + break; default: retdata->err_val = SBI_ERR_NOT_SUPPORTED; }