Re: [PATCH v5 14/22] RISC-V: KVM: Support 64 bit firmware counters on RV32

On Wed, Apr 03, 2024 at 01:04:43AM -0700, Atish Patra wrote:

The SBI v2.0 introduced a fw_read_hi function to read 64 bit firmware counters for RV32 based systems.

Add infrastructure to support that.

Reviewed-by: Anup Patel anup@brainfault.org Signed-off-by: Atish Patra atishp@rivosinc.com

---

arch/riscv/include/asm/kvm_vcpu_pmu.h | 4 ++- arch/riscv/kvm/vcpu_pmu.c | 44 ++++++++++++++++++++++++++- arch/riscv/kvm/vcpu_sbi_pmu.c | 6 ++++ 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_pmu.h b/arch/riscv/include/asm/kvm_vcpu_pmu.h index 257f17641e00..55861b5d3382 100644 --- a/arch/riscv/include/asm/kvm_vcpu_pmu.h +++ b/arch/riscv/include/asm/kvm_vcpu_pmu.h @@ -20,7 +20,7 @@ static_assert(RISCV_KVM_MAX_COUNTERS <= 64); struct kvm_fw_event { /* Current value of the event */

• unsigned long value;

• u64 value;

/* Event monitoring status */ bool started; @@ -91,6 +91,8 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba struct kvm_vcpu_sbi_return *retdata); int kvm_riscv_vcpu_pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx, struct kvm_vcpu_sbi_return *retdata); +int kvm_riscv_vcpu_pmu_fw_ctr_read_hi(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_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long saddr_low, unsigned long saddr_high, unsigned long flags, diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index 9fedf9dc498b..ff326152eeff 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -197,6 +197,36 @@ static int pmu_get_pmc_index(struct kvm_pmu *pmu, unsigned long eidx, return kvm_pmu_get_programmable_pmc_index(pmu, eidx, cbase, cmask); } +static int pmu_fw_ctr_read_hi(struct kvm_vcpu *vcpu, unsigned long cidx,

• 	      unsigned long *out_val)
  

+{

• struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
• struct kvm_pmc *pmc;
• int fevent_code;
• if (!IS_ENABLED(CONFIG_32BIT)) {

• pr_warn("%s: should be invoked for only RV32\n", __func__);
  

• return -EINVAL;
  

• }
• if (cidx >= kvm_pmu_num_counters(kvpmu) || cidx == 1) {

• pr_warn("Invalid counter id [%ld]during read\n", cidx);
  

• return -EINVAL;
  

• }
• pmc = &kvpmu->pmc[cidx];
• if (pmc->cinfo.type != SBI_PMU_CTR_TYPE_FW)

• return -EINVAL;
  

• fevent_code = get_event_code(pmc->event_idx);
• pmc->counter_val = kvpmu->fw_event[fevent_code].value;
• *out_val = pmc->counter_val >> 32;
• return 0;

+}

static int pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx, unsigned long *out_val) { @@ -705,6 +735,18 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba return 0; } +int kvm_riscv_vcpu_pmu_fw_ctr_read_hi(struct kvm_vcpu *vcpu, unsigned long cidx,

• 		      struct kvm_vcpu_sbi_return *retdata)
  

+{

• int ret;
• ret = pmu_fw_ctr_read_hi(vcpu, cidx, &retdata->out_val);
• if (ret == -EINVAL)

• retdata->err_val = SBI_ERR_INVALID_PARAM;
  

• return 0;

+}

int kvm_riscv_vcpu_pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx, struct kvm_vcpu_sbi_return *retdata) { @@ -778,7 +820,7 @@ void kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu) pmc->cinfo.csr = CSR_CYCLE + i; } else { pmc->cinfo.type = SBI_PMU_CTR_TYPE_FW;

• 	pmc->cinfo.width = BITS_PER_LONG - 1;
  

• 	pmc->cinfo.width = 63;
  

  } }

diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c index d3e7625fb2d2..cf111de51bdb 100644 --- a/arch/riscv/kvm/vcpu_sbi_pmu.c +++ b/arch/riscv/kvm/vcpu_sbi_pmu.c @@ -64,6 +64,12 @@ 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_COUNTER_FW_READ_HI:

• if (IS_ENABLED(CONFIG_32BIT))
  

• 	ret = kvm_riscv_vcpu_pmu_fw_ctr_read_hi(vcpu, cp->a0, retdata);
  

• else
  

• 	retdata->out_val = 0;
  

• break;
  

  case SBI_EXT_PMU_SNAPSHOT_SET_SHMEM: ret = kvm_riscv_vcpu_pmu_snapshot_set_shmem(vcpu, cp->a0, cp->a1, cp->a2, retdata); break;

-- 2.34.1

Reviewed-by: Andrew Jones ajones@ventanamicro.com