Commit cbddc4c4 authored by Atish Patra's avatar Atish Patra Committed by Anup Patel
Browse files

RISC-V: KVM: Add SBI PMU extension support 



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: default avatarAnup Patel <anup@brainfault.org>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Signed-off-by: default avatarAtish Patra <atishp@rivosinc.com>
Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 8f0153ec

arch/riscv/kvm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/riscv/kvm/vcpu_sbi.c

+11 −0
Original line number Diff line number Diff line
@@ -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,

};

arch/riscv/kvm/vcpu_sbi_pmu.c

0 → 100644
+86 −0
Original line number Diff line number Diff line 
// 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,

};