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RISC-V: KVM: Initial skeletal support for AIA
To incrementally implement AIA support, we first add minimal skeletal support which only compiles and detects AIA hardware support at the boot-time but does not provide any functionality. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
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9 files changed

Lines changed: 255 additions & 6 deletions

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‎arch/riscv/include/asm/hwcap.h‎

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@@ -48,6 +48,12 @@
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#define RISCV_ISA_EXT_MAX 64
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#define RISCV_ISA_EXT_NAME_LEN_MAX 32
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#ifdef CONFIG_RISCV_M_MODE
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#define RISCV_ISA_EXT_SxAIA RISCV_ISA_EXT_SMAIA
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#else
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#define RISCV_ISA_EXT_SxAIA RISCV_ISA_EXT_SSAIA
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#endif
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#ifndef __ASSEMBLY__
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#include <linux/jump_label.h>

‎arch/riscv/include/asm/kvm_aia.h‎

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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2021 Western Digital Corporation or its affiliates.
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* Copyright (C) 2022 Ventana Micro Systems Inc.
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*
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* Authors:
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* Anup Patel <apatel@ventanamicro.com>
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*/
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#ifndef __KVM_RISCV_AIA_H
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#define __KVM_RISCV_AIA_H
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#include <linux/jump_label.h>
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#include <linux/kvm_types.h>
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struct kvm_aia {
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/* In-kernel irqchip created */
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bool in_kernel;
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/* In-kernel irqchip initialized */
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bool initialized;
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};
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struct kvm_vcpu_aia {
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};
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#define kvm_riscv_aia_initialized(k) ((k)->arch.aia.initialized)
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#define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel)
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DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available);
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#define kvm_riscv_aia_available() \
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static_branch_unlikely(&kvm_riscv_aia_available)
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static inline void kvm_riscv_vcpu_aia_flush_interrupts(struct kvm_vcpu *vcpu)
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{
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}
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static inline void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu)
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{
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}
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static inline bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu,
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u64 mask)
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{
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return false;
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}
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static inline void kvm_riscv_vcpu_aia_update_hvip(struct kvm_vcpu *vcpu)
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{
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}
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static inline void kvm_riscv_vcpu_aia_load(struct kvm_vcpu *vcpu, int cpu)
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{
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}
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static inline void kvm_riscv_vcpu_aia_put(struct kvm_vcpu *vcpu)
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{
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}
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static inline int kvm_riscv_vcpu_aia_get_csr(struct kvm_vcpu *vcpu,
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unsigned long reg_num,
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unsigned long *out_val)
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{
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*out_val = 0;
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return 0;
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}
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static inline int kvm_riscv_vcpu_aia_set_csr(struct kvm_vcpu *vcpu,
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unsigned long reg_num,
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unsigned long val)
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{
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return 0;
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}
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#define KVM_RISCV_VCPU_AIA_CSR_FUNCS
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static inline int kvm_riscv_vcpu_aia_update(struct kvm_vcpu *vcpu)
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{
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return 1;
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}
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static inline void kvm_riscv_vcpu_aia_reset(struct kvm_vcpu *vcpu)
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{
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}
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static inline int kvm_riscv_vcpu_aia_init(struct kvm_vcpu *vcpu)
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{
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return 0;
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}
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static inline void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu)
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{
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}
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static inline void kvm_riscv_aia_init_vm(struct kvm *kvm)
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{
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}
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static inline void kvm_riscv_aia_destroy_vm(struct kvm *kvm)
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{
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}
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void kvm_riscv_aia_enable(void);
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void kvm_riscv_aia_disable(void);
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int kvm_riscv_aia_init(void);
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void kvm_riscv_aia_exit(void);
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#endif

‎arch/riscv/include/asm/kvm_host.h‎

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@@ -14,6 +14,7 @@
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#include <linux/kvm_types.h>
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#include <linux/spinlock.h>
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#include <asm/hwcap.h>
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#include <asm/kvm_aia.h>
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#include <asm/kvm_vcpu_fp.h>
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#include <asm/kvm_vcpu_insn.h>
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#include <asm/kvm_vcpu_sbi.h>
@@ -94,6 +95,9 @@ struct kvm_arch {
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/* Guest Timer */
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struct kvm_guest_timer timer;
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/* AIA Guest/VM context */
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struct kvm_aia aia;
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};
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struct kvm_cpu_trap {
@@ -221,6 +225,9 @@ struct kvm_vcpu_arch {
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/* SBI context */
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struct kvm_vcpu_sbi_context sbi_context;
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/* AIA VCPU context */
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struct kvm_vcpu_aia aia_context;
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/* Cache pages needed to program page tables with spinlock held */
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struct kvm_mmu_memory_cache mmu_page_cache;
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‎arch/riscv/kvm/Makefile‎

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@@ -26,3 +26,4 @@ kvm-y += vcpu_sbi_replace.o
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kvm-y += vcpu_sbi_hsm.o
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kvm-y += vcpu_timer.o
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kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
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kvm-y += aia.o

‎arch/riscv/kvm/aia.c‎

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// 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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* Copyright (C) 2022 Ventana Micro Systems Inc.
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*
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* Authors:
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* Anup Patel <apatel@ventanamicro.com>
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*/
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#include <linux/kvm_host.h>
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#include <asm/hwcap.h>
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DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available);
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static void aia_set_hvictl(bool ext_irq_pending)
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{
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unsigned long hvictl;
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/*
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* HVICTL.IID == 9 and HVICTL.IPRIO == 0 represents
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* no interrupt in HVICTL.
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*/
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hvictl = (IRQ_S_EXT << HVICTL_IID_SHIFT) & HVICTL_IID;
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hvictl |= ext_irq_pending;
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csr_write(CSR_HVICTL, hvictl);
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}
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void kvm_riscv_aia_enable(void)
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{
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if (!kvm_riscv_aia_available())
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return;
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aia_set_hvictl(false);
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csr_write(CSR_HVIPRIO1, 0x0);
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csr_write(CSR_HVIPRIO2, 0x0);
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#ifdef CONFIG_32BIT
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csr_write(CSR_HVIPH, 0x0);
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csr_write(CSR_HIDELEGH, 0x0);
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csr_write(CSR_HVIPRIO1H, 0x0);
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csr_write(CSR_HVIPRIO2H, 0x0);
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#endif
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}
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void kvm_riscv_aia_disable(void)
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{
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if (!kvm_riscv_aia_available())
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return;
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aia_set_hvictl(false);
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}
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int kvm_riscv_aia_init(void)
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{
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if (!riscv_isa_extension_available(NULL, SxAIA))
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return -ENODEV;
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/* Enable KVM AIA support */
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static_branch_enable(&kvm_riscv_aia_available);
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return 0;
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}
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void kvm_riscv_aia_exit(void)
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{
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}

‎arch/riscv/kvm/main.c‎

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@@ -44,11 +44,15 @@ int kvm_arch_hardware_enable(void)
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csr_write(CSR_HVIP, 0);
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kvm_riscv_aia_enable();
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return 0;
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}
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void kvm_arch_hardware_disable(void)
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{
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kvm_riscv_aia_disable();
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/*
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* After clearing the hideleg CSR, the host kernel will receive
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* spurious interrupts if hvip CSR has pending interrupts and the
@@ -63,6 +67,7 @@ void kvm_arch_hardware_disable(void)
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static int __init riscv_kvm_init(void)
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{
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int rc;
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const char *str;
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if (!riscv_isa_extension_available(NULL, h)) {
@@ -84,6 +89,10 @@ static int __init riscv_kvm_init(void)
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kvm_riscv_gstage_vmid_detect();
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rc = kvm_riscv_aia_init();
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if (rc && rc != -ENODEV)
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return rc;
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kvm_info("hypervisor extension available\n");
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switch (kvm_riscv_gstage_mode()) {
@@ -106,12 +115,23 @@ static int __init riscv_kvm_init(void)
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kvm_info("VMID %ld bits available\n", kvm_riscv_gstage_vmid_bits());
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return kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
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if (kvm_riscv_aia_available())
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kvm_info("AIA available\n");
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rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
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if (rc) {
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kvm_riscv_aia_exit();
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return rc;
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}
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return 0;
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}
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module_init(riscv_kvm_init);
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static void __exit riscv_kvm_exit(void)
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{
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kvm_riscv_aia_exit();
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kvm_exit();
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}
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module_exit(riscv_kvm_exit);

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