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The SBI v0.3 specification extends SBI HSM extension by adding SBI HSM suspend call and related HART states. This patch extends the KVM RISC-V HSM implementation to provide KVM guest a minimal SBI HSM suspend call which is equivalent to a WFI instruction. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
120 lines
2.7 KiB
C
120 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2021 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Atish Patra <atish.patra@wdc.com>
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*/
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/kvm_host.h>
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#include <asm/csr.h>
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#include <asm/sbi.h>
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#include <asm/kvm_vcpu_sbi.h>
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static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)
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{
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struct kvm_cpu_context *reset_cntx;
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struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
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struct kvm_vcpu *target_vcpu;
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unsigned long target_vcpuid = cp->a0;
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target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
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if (!target_vcpu)
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return -EINVAL;
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if (!target_vcpu->arch.power_off)
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return -EALREADY;
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reset_cntx = &target_vcpu->arch.guest_reset_context;
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/* start address */
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reset_cntx->sepc = cp->a1;
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/* target vcpu id to start */
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reset_cntx->a0 = target_vcpuid;
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/* private data passed from kernel */
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reset_cntx->a1 = cp->a2;
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kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu);
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kvm_riscv_vcpu_power_on(target_vcpu);
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return 0;
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}
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static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
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{
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if (vcpu->arch.power_off)
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return -EINVAL;
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kvm_riscv_vcpu_power_off(vcpu);
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return 0;
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}
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static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
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{
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struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
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unsigned long target_vcpuid = cp->a0;
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struct kvm_vcpu *target_vcpu;
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target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
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if (!target_vcpu)
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return -EINVAL;
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if (!target_vcpu->arch.power_off)
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return SBI_HSM_STATE_STARTED;
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else if (vcpu->stat.generic.blocking)
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return SBI_HSM_STATE_SUSPENDED;
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else
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return SBI_HSM_STATE_STOPPED;
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}
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static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
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unsigned long *out_val,
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struct kvm_cpu_trap *utrap,
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bool *exit)
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{
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int ret = 0;
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struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
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struct kvm *kvm = vcpu->kvm;
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unsigned long funcid = cp->a6;
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switch (funcid) {
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case SBI_EXT_HSM_HART_START:
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mutex_lock(&kvm->lock);
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ret = kvm_sbi_hsm_vcpu_start(vcpu);
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mutex_unlock(&kvm->lock);
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break;
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case SBI_EXT_HSM_HART_STOP:
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ret = kvm_sbi_hsm_vcpu_stop(vcpu);
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break;
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case SBI_EXT_HSM_HART_STATUS:
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ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
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if (ret >= 0) {
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*out_val = ret;
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ret = 0;
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}
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break;
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case SBI_EXT_HSM_HART_SUSPEND:
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switch (cp->a0) {
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case SBI_HSM_SUSPEND_RET_DEFAULT:
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kvm_riscv_vcpu_wfi(vcpu);
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break;
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case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
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ret = -EOPNOTSUPP;
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break;
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default:
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ret = -EINVAL;
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}
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break;
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default:
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ret = -EOPNOTSUPP;
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}
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return ret;
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}
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const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {
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.extid_start = SBI_EXT_HSM,
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.extid_end = SBI_EXT_HSM,
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.handler = kvm_sbi_ext_hsm_handler,
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};
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