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    Subject[PATCH v3 08/14] RISC-V: KVM: Add SBI PMU extension support
    Date
    SBI PMU extension allows KVM guests to configure/start/stop/query about
    the PMU counters in virtualized enviornment as well.

    In order to allow that, KVM implements the entire SBI PMU extension.

    Signed-off-by: Atish Patra <atishp@rivosinc.com>
    ---
    arch/riscv/kvm/Makefile | 2 +-
    arch/riscv/kvm/vcpu_sbi.c | 11 +++++
    arch/riscv/kvm/vcpu_sbi_pmu.c | 86 +++++++++++++++++++++++++++++++++++
    3 files changed, 98 insertions(+), 1 deletion(-)
    create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c

    diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
    index 5de1053..278e97c 100644
    --- a/arch/riscv/kvm/Makefile
    +++ b/arch/riscv/kvm/Makefile
    @@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
    kvm-y += vcpu_sbi_replace.o
    kvm-y += vcpu_sbi_hsm.o
    kvm-y += vcpu_timer.o
    -kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
    +kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
    diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
    index aa42da6..04a3b4b 100644
    --- a/arch/riscv/kvm/vcpu_sbi.c
    +++ b/arch/riscv/kvm/vcpu_sbi.c
    @@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
    };
    #endif

    +#ifdef CONFIG_RISCV_PMU_SBI
    +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
    +#else
    +static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
    + .extid_start = -1UL,
    + .extid_end = -1UL,
    + .handler = NULL,
    +};
    +#endif
    +
    static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
    &vcpu_sbi_ext_v01,
    &vcpu_sbi_ext_base,
    @@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
    &vcpu_sbi_ext_rfence,
    &vcpu_sbi_ext_srst,
    &vcpu_sbi_ext_hsm,
    + &vcpu_sbi_ext_pmu,
    &vcpu_sbi_ext_experimental,
    &vcpu_sbi_ext_vendor,
    };
    diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
    new file mode 100644
    index 0000000..73aab30
    --- /dev/null
    +++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
    @@ -0,0 +1,86 @@
    +// SPDX-License-Identifier: GPL-2.0
    +/*
    + * Copyright (c) 2023 Rivos Inc
    + *
    + * Authors:
    + * Atish Patra <atishp@rivosinc.com>
    + */
    +
    +#include <linux/errno.h>
    +#include <linux/err.h>
    +#include <linux/kvm_host.h>
    +#include <asm/csr.h>
    +#include <asm/sbi.h>
    +#include <asm/kvm_vcpu_sbi.h>
    +
    +static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
    + struct kvm_vcpu_sbi_ext_data *edata,
    + struct kvm_cpu_trap *utrap)
    +{
    + int ret = 0;
    + struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
    + struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
    + unsigned long funcid = cp->a6;
    + uint64_t temp;
    +
    + /* Return not supported if PMU is not initialized */
    + if (!kvpmu->init_done)
    + return -EINVAL;
    +
    + switch (funcid) {
    + case SBI_EXT_PMU_NUM_COUNTERS:
    + ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, edata);
    + break;
    + case SBI_EXT_PMU_COUNTER_GET_INFO:
    + ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, edata);
    + break;
    + case SBI_EXT_PMU_COUNTER_CFG_MATCH:
    +#if defined(CONFIG_32BIT)
    + temp = ((uint64_t)cp->a5 << 32) | cp->a4;
    +#else
    + temp = cp->a4;
    +#endif
    + /*
    + * This can fail if perf core framework fails to create an event.
    + * Forward the error to the user space because its an error happened
    + * within host kernel. The other option would be convert this to
    + * an SBI error and forward to the guest.
    + */
    + ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
    + cp->a2, cp->a3, temp, edata);
    + break;
    + case SBI_EXT_PMU_COUNTER_START:
    +#if defined(CONFIG_32BIT)
    + temp = ((uint64_t)cp->a4 << 32) | cp->a3;
    +#else
    + temp = cp->a3;
    +#endif
    + ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
    + temp, edata);
    + break;
    + case SBI_EXT_PMU_COUNTER_STOP:
    + ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, edata);
    + break;
    + case SBI_EXT_PMU_COUNTER_FW_READ:
    + ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, edata);
    + break;
    + default:
    + edata->err_val = SBI_ERR_NOT_SUPPORTED;
    + }
    +
    + return ret;
    +}
    +
    +unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
    +{
    + struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
    +
    + return kvpmu->init_done;
    +}
    +
    +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
    + .extid_start = SBI_EXT_PMU,
    + .extid_end = SBI_EXT_PMU,
    + .handler = kvm_sbi_ext_pmu_handler,
    + .probe = kvm_sbi_ext_pmu_probe,
    +};
    --
    2.25.1
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