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Message-ID: <20230113120854.axtnxmykmwh2ixeb@orel>
Date: Fri, 13 Jan 2023 13:08:54 +0100
From: Andrew Jones <ajones@...tanamicro.com>
To: Atish Patra <atishp@...osinc.com>
Cc: linux-kernel@...r.kernel.org, Anup Patel <anup@...infault.org>,
Atish Patra <atishp@...shpatra.org>,
Guo Ren <guoren@...nel.org>, kvm-riscv@...ts.infradead.org,
kvm@...r.kernel.org, linux-riscv@...ts.infradead.org,
Mark Rutland <mark.rutland@....com>,
Palmer Dabbelt <palmer@...belt.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Sergey Matyukevich <sergey.matyukevich@...tacore.com>,
Eric Lin <eric.lin@...ive.com>, Will Deacon <will@...nel.org>
Subject: Re: [PATCH v2 11/11] RISC-V: KVM: Implement firmware events
On Thu, Dec 15, 2022 at 09:00:46AM -0800, Atish Patra wrote:
> SBI PMU extension defines a set of firmware events which can provide
> useful information to guests about number of SBI calls. As hypervisor
> implements the SBI PMU extension, these firmware events corresponds
> to ecall invocations between VS->HS mode. All other firmware events
> will always report zero if monitored as KVM doesn't implement them.
>
> Signed-off-by: Atish Patra <atishp@...osinc.com>
> ---
> arch/riscv/include/asm/kvm_vcpu_pmu.h | 16 ++++
> arch/riscv/include/asm/sbi.h | 2 +-
> arch/riscv/kvm/tlb.c | 6 +-
> arch/riscv/kvm/vcpu_pmu.c | 105 ++++++++++++++++++++++----
> arch/riscv/kvm/vcpu_sbi_replace.c | 7 ++
> 5 files changed, 119 insertions(+), 17 deletions(-)
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_pmu.h b/arch/riscv/include/asm/kvm_vcpu_pmu.h
> index 7a9a8e6..cccc6182 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_pmu.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_pmu.h
> @@ -17,6 +17,14 @@
> #define RISCV_KVM_MAX_FW_CTRS 32
> #define RISCV_MAX_COUNTERS 64
>
> +struct kvm_fw_event {
> + /* Current value of the event */
> + unsigned long value;
> +
> + /* Event monitoring status */
> + bool started;
> +};
> +
> /* Per virtual pmu counter data */
> struct kvm_pmc {
> u8 idx;
> @@ -25,11 +33,14 @@ struct kvm_pmc {
> union sbi_pmu_ctr_info cinfo;
> /* Event monitoring status */
> bool started;
> + /* Monitoring event ID */
> + unsigned long event_idx;
> };
>
> /* PMU data structure per vcpu */
> struct kvm_pmu {
> struct kvm_pmc pmc[RISCV_MAX_COUNTERS];
> + struct kvm_fw_event fw_event[RISCV_KVM_MAX_FW_CTRS];
> /* Number of the virtual firmware counters available */
> int num_fw_ctrs;
> /* Number of the virtual hardware counters available */
> @@ -52,6 +63,7 @@ struct kvm_pmu {
> { .base = CSR_CYCLE, .count = 31, .func = kvm_riscv_vcpu_pmu_read_hpm },
> #endif
>
> +int kvm_riscv_vcpu_pmu_incr_fw(struct kvm_vcpu *vcpu, unsigned long fid);
> int kvm_riscv_vcpu_pmu_read_hpm(struct kvm_vcpu *vcpu, unsigned int csr_num,
> unsigned long *val, unsigned long new_val,
> unsigned long wr_mask);
> @@ -81,6 +93,10 @@ struct kvm_pmu {
> #define KVM_RISCV_VCPU_HPMCOUNTER_CSR_FUNCS \
> { .base = 0, .count = 0, .func = NULL },
>
> +static inline int kvm_riscv_vcpu_pmu_incr_fw(struct kvm_vcpu *vcpu, unsigned long fid)
> +{
> + return 0;
> +}
>
> static inline int kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu)
> {
> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> index 2a0ef738..a192a95a 100644
> --- a/arch/riscv/include/asm/sbi.h
> +++ b/arch/riscv/include/asm/sbi.h
> @@ -171,7 +171,7 @@ enum sbi_pmu_fw_generic_events_t {
> SBI_PMU_FW_IPI_SENT = 6,
> SBI_PMU_FW_IPI_RECVD = 7,
> SBI_PMU_FW_FENCE_I_SENT = 8,
> - SBI_PMU_FW_FENCE_I_RECVD = 9,
> + SBI_PMU_FW_FENCE_I_RCVD = 9,
This should probably be in its own patch.
> SBI_PMU_FW_SFENCE_VMA_SENT = 10,
> SBI_PMU_FW_SFENCE_VMA_RCVD = 11,
> SBI_PMU_FW_SFENCE_VMA_ASID_SENT = 12,
> diff --git a/arch/riscv/kvm/tlb.c b/arch/riscv/kvm/tlb.c
> index 309d79b..de81920 100644
> --- a/arch/riscv/kvm/tlb.c
> +++ b/arch/riscv/kvm/tlb.c
> @@ -181,6 +181,7 @@ void kvm_riscv_local_tlb_sanitize(struct kvm_vcpu *vcpu)
>
> void kvm_riscv_fence_i_process(struct kvm_vcpu *vcpu)
> {
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_RCVD);
> local_flush_icache_all();
> }
>
> @@ -264,15 +265,18 @@ void kvm_riscv_hfence_process(struct kvm_vcpu *vcpu)
> d.addr, d.size, d.order);
> break;
> case KVM_RISCV_HFENCE_VVMA_ASID_GVA:
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_ASID_RCVD);
> kvm_riscv_local_hfence_vvma_asid_gva(
> READ_ONCE(v->vmid), d.asid,
> d.addr, d.size, d.order);
> break;
> case KVM_RISCV_HFENCE_VVMA_ASID_ALL:
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_ASID_RCVD);
> kvm_riscv_local_hfence_vvma_asid_all(
> READ_ONCE(v->vmid), d.asid);
> break;
> case KVM_RISCV_HFENCE_VVMA_GVA:
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_RCVD);
> kvm_riscv_local_hfence_vvma_gva(
> READ_ONCE(v->vmid),
> d.addr, d.size, d.order);
> @@ -323,7 +327,7 @@ void kvm_riscv_fence_i(struct kvm *kvm,
> unsigned long hbase, unsigned long hmask)
> {
> make_xfence_request(kvm, hbase, hmask, KVM_REQ_FENCE_I,
> - KVM_REQ_FENCE_I, NULL);
> + KVM_REQ_FENCE_I, NULL);
stray change, and whitespace was correct before
> }
>
> void kvm_riscv_hfence_gvma_vmid_gpa(struct kvm *kvm,
> diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
> index 21c1f0f..a64a7ae 100644
> --- a/arch/riscv/kvm/vcpu_pmu.c
> +++ b/arch/riscv/kvm/vcpu_pmu.c
> @@ -170,18 +170,36 @@ static int pmu_get_pmc_index(struct kvm_pmu *pmu, unsigned long eidx,
> return pmu_get_programmable_pmc_index(pmu, eidx, cbase, cmask);
> }
>
> +int kvm_riscv_vcpu_pmu_incr_fw(struct kvm_vcpu *vcpu, unsigned long fid)
> +{
> + struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> + struct kvm_fw_event *fevent;
> +
> + if (!kvpmu || fid >= SBI_PMU_FW_MAX)
> + return -EINVAL;
> +
> + fevent = &kvpmu->fw_event[fid];
> + if (fevent->started)
> + fevent->value++;
> +
> + return 0;
> +}
> +
> static int pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx,
> unsigned long *out_val)
> {
> struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> struct kvm_pmc *pmc;
> u64 enabled, running;
> + int fevent_code;
>
> pmc = &kvpmu->pmc[cidx];
> - if (!pmc->perf_event)
> - return -EINVAL;
>
> - pmc->counter_val += perf_event_read_value(pmc->perf_event, &enabled, &running);
> + if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) {
> + fevent_code = get_event_code(pmc->event_idx);
> + 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);
> *out_val = pmc->counter_val;
>
> return 0;
> @@ -238,6 +256,7 @@ int kvm_riscv_vcpu_pmu_ctr_start(struct kvm_vcpu *vcpu, unsigned long ctr_base,
> struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> int i, num_ctrs, pmc_index, sbiret = 0;
> struct kvm_pmc *pmc;
> + int fevent_code;
>
> num_ctrs = kvpmu->num_fw_ctrs + kvpmu->num_hw_ctrs;
> if (ctr_base + __fls(ctr_mask) >= num_ctrs) {
> @@ -253,7 +272,22 @@ int kvm_riscv_vcpu_pmu_ctr_start(struct kvm_vcpu *vcpu, unsigned long ctr_base,
> pmc = &kvpmu->pmc[pmc_index];
> if (flag & SBI_PMU_START_FLAG_SET_INIT_VALUE)
> pmc->counter_val = ival;
> - if (pmc->perf_event) {
> + if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) {
> + fevent_code = get_event_code(pmc->event_idx);
> + if (fevent_code >= SBI_PMU_FW_MAX) {
> + sbiret = SBI_ERR_INVALID_PARAM;
> + goto out;
> + }
> +
> + /* Check if the counter was already started for some reason */
> + if (kvpmu->fw_event[fevent_code].started) {
> + sbiret = SBI_ERR_ALREADY_STARTED;
> + continue;
> + }
> +
> + kvpmu->fw_event[fevent_code].started = true;
> + kvpmu->fw_event[fevent_code].value = pmc->counter_val;
> + } else if (pmc->perf_event) {
> if (unlikely(pmc->started)) {
> sbiret = SBI_ERR_ALREADY_STARTED;
> continue;
> @@ -281,6 +315,7 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base,
> int i, num_ctrs, pmc_index, sbiret = 0;
> u64 enabled, running;
> struct kvm_pmc *pmc;
> + int fevent_code;
>
> num_ctrs = kvpmu->num_fw_ctrs + kvpmu->num_hw_ctrs;
> if ((ctr_base + __fls(ctr_mask)) >= num_ctrs) {
> @@ -294,7 +329,18 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base,
> if (!test_bit(pmc_index, kvpmu->pmc_in_use))
> continue;
> pmc = &kvpmu->pmc[pmc_index];
> - if (pmc->perf_event) {
> + if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) {
> + fevent_code = get_event_code(pmc->event_idx);
> + if (fevent_code >= SBI_PMU_FW_MAX) {
> + sbiret = SBI_ERR_INVALID_PARAM;
> + goto out;
> + }
> +
> + if (!kvpmu->fw_event[fevent_code].started)
> + sbiret = SBI_ERR_ALREADY_STOPPED;
> +
> + kvpmu->fw_event[fevent_code].started = false;
> + } else if (pmc->perf_event) {
> if (pmc->started) {
> /* Stop counting the counter */
> perf_event_disable(pmc->perf_event);
> @@ -307,12 +353,15 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base,
> pmc->counter_val += perf_event_read_value(pmc->perf_event,
> &enabled, &running);
> pmu_release_perf_event(pmc);
> - clear_bit(pmc_index, kvpmu->pmc_in_use);
> }
> } else {
> kvm_debug("Can not stop counter due to invalid confiugartion\n");
> sbiret = SBI_ERR_INVALID_PARAM;
> }
> + if (flag & SBI_PMU_STOP_FLAG_RESET) {
> + pmc->event_idx = SBI_PMU_EVENT_IDX_INVALID;
> + clear_bit(pmc_index, kvpmu->pmc_in_use);
nit: I'd probably just leave clear_bit where it was and add
if (flag & SBI_PMU_STOP_FLAG_RESET)
pmc->event_idx = SBI_PMU_EVENT_IDX_INVALID;
to the firmware arm.
> + }
> }
>
> out:
> @@ -329,12 +378,12 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
> struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> struct perf_event *event;
> struct perf_event_attr attr;
> - int num_ctrs, ctr_idx;
> + int num_ctrs, ctr_idx, sbiret = 0;
> u32 etype = pmu_get_perf_event_type(eidx);
> u64 config;
> - struct kvm_pmc *pmc;
> - int sbiret = 0;
> -
> + struct kvm_pmc *pmc = NULL;
> + bool is_fevent;
> + unsigned long event_code;
>
> num_ctrs = kvpmu->num_fw_ctrs + kvpmu->num_hw_ctrs;
> if (etype == PERF_TYPE_MAX || (ctr_base + __fls(ctr_mask) >= num_ctrs)) {
> @@ -342,7 +391,9 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
> goto out;
> }
>
> - if (pmu_is_fw_event(eidx)) {
> + event_code = get_event_code(eidx);
> + is_fevent = pmu_is_fw_event(eidx);
> + if (is_fevent && event_code >= SBI_PMU_FW_MAX) {
> sbiret = SBI_ERR_NOT_SUPPORTED;
> goto out;
> }
> @@ -357,7 +408,10 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
> goto out;
> }
> ctr_idx = ctr_base;
> - goto match_done;
> + if (is_fevent)
> + goto perf_event_done;
> + else
> + goto match_done;
> }
>
> ctr_idx = pmu_get_pmc_index(kvpmu, eidx, ctr_base, ctr_mask);
> @@ -366,6 +420,13 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
> goto out;
> }
>
> + /*
> + * No need to create perf events for firmware events as the firmware counter
> + * is supposed to return the measurement of VS->HS mode invocations.
> + */
> + if (is_fevent)
> + goto perf_event_done;
> +
> match_done:
> pmc = &kvpmu->pmc[ctr_idx];
> pmu_release_perf_event(pmc);
> @@ -404,10 +465,19 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
> return -EOPNOTSUPP;
> }
>
> - set_bit(ctr_idx, kvpmu->pmc_in_use);
> pmc->perf_event = event;
> - if (flag & SBI_PMU_CFG_FLAG_AUTO_START)
> - perf_event_enable(pmc->perf_event);
Maybe we can move the perf setup stuff into a helper function and
then guard it with an if-statement rather than have the gotos?
> +perf_event_done:
> + if (flag & SBI_PMU_CFG_FLAG_AUTO_START) {
> + if (is_fevent)
> + kvpmu->fw_event[event_code].started = true;
> + else
> + perf_event_enable(pmc->perf_event);
> + }
> + /* This should be only true for firmware events */
> + if (!pmc)
> + pmc = &kvpmu->pmc[ctr_idx];
> + pmc->event_idx = eidx;
> + set_bit(ctr_idx, kvpmu->pmc_in_use);
>
> ext_data->out_val = ctr_idx;
> out:
> @@ -451,6 +521,7 @@ int kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu)
> bitmap_zero(kvpmu->pmc_in_use, RISCV_MAX_COUNTERS);
> kvpmu->num_hw_ctrs = num_hw_ctrs;
> kvpmu->num_fw_ctrs = num_fw_ctrs;
> + memset(&kvpmu->fw_event, 0, SBI_PMU_FW_MAX * sizeof(struct kvm_fw_event));
I'm wondering if we need this array. We already have an underused pmc for
the fw events which has counter_val and started. Can't we just used those?
> /*
> * There is no corelation betwen the logical hardware counter and virtual counters.
> * However, we need to encode a hpmcounter CSR in the counter info field so that
> @@ -464,6 +535,7 @@ int kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu)
> pmc = &kvpmu->pmc[i];
> pmc->idx = i;
> pmc->counter_val = 0;
> + pmc->event_idx = SBI_PMU_EVENT_IDX_INVALID;
> if (i < kvpmu->num_hw_ctrs) {
> kvpmu->pmc[i].cinfo.type = SBI_PMU_CTR_TYPE_HW;
> if (i < 3)
> @@ -501,7 +573,10 @@ void kvm_riscv_vcpu_pmu_deinit(struct kvm_vcpu *vcpu)
> for_each_set_bit(i, kvpmu->pmc_in_use, RISCV_MAX_COUNTERS) {
> pmc = &kvpmu->pmc[i];
> pmu_release_perf_event(pmc);
> + pmc->counter_val = 0;
> + pmc->event_idx = SBI_PMU_EVENT_IDX_INVALID;
> }
> + memset(&kvpmu->fw_event, 0, SBI_PMU_FW_MAX * sizeof(struct kvm_fw_event));
> }
>
> void kvm_riscv_vcpu_pmu_reset(struct kvm_vcpu *vcpu)
> diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
> index d029136..3f39711 100644
> --- a/arch/riscv/kvm/vcpu_sbi_replace.c
> +++ b/arch/riscv/kvm/vcpu_sbi_replace.c
> @@ -11,6 +11,7 @@
> #include <linux/kvm_host.h>
> #include <asm/sbi.h>
> #include <asm/kvm_vcpu_timer.h>
> +#include <asm/kvm_vcpu_pmu.h>
> #include <asm/kvm_vcpu_sbi.h>
>
> static int kvm_sbi_ext_time_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> @@ -26,6 +27,7 @@ static int kvm_sbi_ext_time_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> return 0;
> }
>
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_SET_TIMER);
> #if __riscv_xlen == 32
> next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
> #else
> @@ -58,6 +60,7 @@ static int kvm_sbi_ext_ipi_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> return 0;
> }
>
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_IPI_SENT);
> kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
> if (hbase != -1UL) {
> if (tmp->vcpu_id < hbase)
> @@ -68,6 +71,7 @@ static int kvm_sbi_ext_ipi_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> ret = kvm_riscv_vcpu_set_interrupt(tmp, IRQ_VS_SOFT);
> if (ret < 0)
> break;
> + kvm_riscv_vcpu_pmu_incr_fw(tmp, SBI_PMU_FW_IPI_RECVD);
> }
>
> return ret;
> @@ -91,6 +95,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
> switch (funcid) {
> case SBI_EXT_RFENCE_REMOTE_FENCE_I:
> kvm_riscv_fence_i(vcpu->kvm, hbase, hmask);
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_FENCE_I_SENT);
> break;
> case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
> if (cp->a2 == 0 && cp->a3 == 0)
> @@ -98,6 +103,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
> else
> kvm_riscv_hfence_vvma_gva(vcpu->kvm, hbase, hmask,
> cp->a2, cp->a3, PAGE_SHIFT);
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_SENT);
> break;
> case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
> if (cp->a2 == 0 && cp->a3 == 0)
> @@ -108,6 +114,7 @@ static int kvm_sbi_ext_rfence_handler(struct kvm_vcpu *vcpu, struct kvm_run *run
> hbase, hmask,
> cp->a2, cp->a3,
> PAGE_SHIFT, cp->a4);
> + kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_HFENCE_VVMA_ASID_SENT);
> break;
> case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA:
> case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID:
> --
> 2.25.1
>
It think it'd be nice to break the application of
kvm_riscv_vcpu_pmu_incr_fw() out of this patch. I.e. introduce
kvm_riscv_vcpu_pmu_incr_fw() in this patch and then a second patch
applies it to all the ecalls.
Thanks,
drew
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