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RISC-V: KVM: Add SBI PMU extension support

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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.

Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Atish Patra 2023-02-07 01:55:23 -08:00 committed by Anup Patel
parent 8f0153ecd3
commit cbddc4c4cb
3 changed files with 98 additions and 1 deletions
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2
arch/riscv/kvm/Makefile
View file

@ -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

11
arch/riscv/kvm/vcpu_sbi.c
View file

@ -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,
};

86
arch/riscv/kvm/vcpu_sbi_pmu.c Normal file
View file

@ -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_return *retdata)
{
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;
u64 temp;
if (!kvpmu->init_done) {
retdata->err_val = SBI_ERR_NOT_SUPPORTED;
return 0;
}
switch (funcid) {
case SBI_EXT_PMU_NUM_COUNTERS:
ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
break;
case SBI_EXT_PMU_COUNTER_GET_INFO:
ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
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 userspace because it's an error which
* happened within the host kernel. The other option would be
* to convert 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, retdata);
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, retdata);
break;
case SBI_EXT_PMU_COUNTER_STOP:
ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
break;
case SBI_EXT_PMU_COUNTER_FW_READ:
ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
break;
default:
retdata->err_val = SBI_ERR_NOT_SUPPORTED;
}
return ret;
}
static 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,
};