[RFC 9/9] RISC-V: KVM: Support 64 bit firmware counters on RV32
Atish Patra
atishp at rivosinc.com
Mon Dec 4 18:43:10 PST 2023
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.
Signed-off-by: Atish Patra <atishp at rivosinc.com>
---
arch/riscv/include/asm/kvm_vcpu_pmu.h | 6 ++++-
arch/riscv/kvm/vcpu_pmu.c | 38 ++++++++++++++++++++++++++-
arch/riscv/kvm/vcpu_sbi_pmu.c | 7 +++++
3 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_vcpu_pmu.h b/arch/riscv/include/asm/kvm_vcpu_pmu.h
index 64c75acad6ba..dd655315e706 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;
+ uint64_t value;
/* Event monitoring status */
bool started;
@@ -91,6 +91,10 @@ 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);
+#if defined(CONFIG_32BIT)
+int kvm_riscv_vcpu_pmu_fw_ctr_read_hi(struct kvm_vcpu *vcpu, unsigned long cidx,
+ struct kvm_vcpu_sbi_return *retdata);
+#endif
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,
diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index 86c8e92f92d3..5b4a93647256 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -195,6 +195,28 @@ static int pmu_get_pmc_index(struct kvm_pmu *pmu, unsigned long eidx,
return kvm_pmu_get_programmable_pmc_index(pmu, eidx, cbase, cmask);
}
+#if defined(CONFIG_32BIT)
+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;
+ u64 enabled, running;
+ int fevent_code;
+
+ 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;
+}
+#endif
static int pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx,
unsigned long *out_val)
@@ -696,6 +718,20 @@ int kvm_riscv_vcpu_pmu_ctr_cfg_match(struct kvm_vcpu *vcpu, unsigned long ctr_ba
return 0;
}
+#if defined(CONFIG_32BIT)
+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;
+}
+#endif
+
int kvm_riscv_vcpu_pmu_ctr_read(struct kvm_vcpu *vcpu, unsigned long cidx,
struct kvm_vcpu_sbi_return *retdata)
{
@@ -769,7 +805,7 @@ 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 77c20a61fd7d..0cd051d5a448 100644
--- a/arch/riscv/kvm/vcpu_sbi_pmu.c
+++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
@@ -64,6 +64,13 @@ 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 defined(CONFIG_32BIT)
+ ret = kvm_riscv_vcpu_pmu_fw_ctr_read_hi(vcpu, cp->a0, retdata);
+#else
+ retdata->out_val = 0;
+#endif
+ break;
case SBI_EXT_PMU_SNAPSHOT_SET_SHMEM:
ret = kvm_riscv_vcpu_pmu_setup_snapshot(vcpu, cp->a0, cp->a1, cp->a2, retdata);
break;
--
2.34.1
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