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Subject: Re: [PATCH v21 02/29] LoongArch: KVM: Implement kvm module related
 interface
To:     Huacai Chen <chenhuacai@kernel.org>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        WANG Xuerui <kernel@xen0n.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        loongarch@lists.linux.dev, Jens Axboe <axboe@kernel.dk>,
        Mark Brown <broonie@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Oliver Upton <oliver.upton@linux.dev>, maobibo@loongson.cn,
        Xi Ruoyao <xry111@xry111.site>
References: <20230915014949.1222777-1-zhaotianrui@loongson.cn>
 <20230915014949.1222777-3-zhaotianrui@loongson.cn>
 <CAAhV-H5MEEACwp-NAPMWDhv31YT9cqJE6o8Z_O3UtHepyKF81g@mail.gmail.com>
 <a6a8ce42-54ad-659a-95c9-c5f47f74aecd@loongson.cn>
 <CAAhV-H4SO4sDV5o9+hMGL65qsh-0X9f68FaKY7TkrNOQ+G3_wA@mail.gmail.com>
From:   zhaotianrui <zhaotianrui@loongson.cn>
Message-ID: <3398bb30-a66a-c2ee-9f1f-da5e05db3a96@loongson.cn>
Date:   Tue, 19 Sep 2023 13:07:29 +0800
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在 2023/9/19 上午10:41, Huacai Chen 写道:
> On Tue, Sep 19, 2023 at 10:38 AM zhaotianrui <zhaotianrui@loongson.cn> wrote:
>>
>> 在 2023/9/17 下午12:21, Huacai Chen 写道:
>>> Hi, Tianrui,
>>>
>>> On Fri, Sep 15, 2023 at 9:50 AM Tianrui Zhao <zhaotianrui@loongson.cn> wrote:
>>>> Implement LoongArch kvm module init, module exit interface,
>>>> using kvm context to save the vpid info and vcpu world switch
>>>> interface pointer.
>>>>
>>>> Reviewed-by: Bibo Mao <maobibo@loongson.cn>
>>>> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
>>>> ---
>>>>    arch/loongarch/kvm/main.c | 367 ++++++++++++++++++++++++++++++++++++++
>>>>    1 file changed, 367 insertions(+)
>>>>    create mode 100644 arch/loongarch/kvm/main.c
>>>>
>>>> diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
>>>> new file mode 100644
>>>> index 0000000000..0deb9273d8
>>>> --- /dev/null
>>>> +++ b/arch/loongarch/kvm/main.c
>>>> @@ -0,0 +1,367 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
>>>> + */
>>>> +
>>>> +#include <linux/err.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/kvm_host.h>
>>>> +#include <asm/cacheflush.h>
>>>> +#include <asm/cpufeature.h>
>>>> +#include <asm/kvm_csr.h>
>>>> +#include "trace.h"
>>>> +
>>>> +static struct kvm_context __percpu *vmcs;
>>>> +struct kvm_world_switch *kvm_loongarch_ops;
>>>> +unsigned long vpid_mask;
>>>> +static int gcsr_flag[CSR_MAX_NUMS];
>>>> +
>>>> +int get_gcsr_flag(int csr)
>>>> +{
>>>> +       if (csr < CSR_MAX_NUMS)
>>>> +               return gcsr_flag[csr];
>>>> +
>>>> +       return INVALID_GCSR;
>>>> +}
>>>> +
>>>> +static inline void set_gcsr_sw_flag(int csr)
>>>> +{
>>>> +       if (csr < CSR_MAX_NUMS)
>>>> +               gcsr_flag[csr] |= SW_GCSR;
>>>> +}
>>>> +
>>>> +static inline void set_gcsr_hw_flag(int csr)
>>>> +{
>>>> +       if (csr < CSR_MAX_NUMS)
>>>> +               gcsr_flag[csr] |= HW_GCSR;
>>>> +}
>>>> +
>>>> +/*
>>>> + * The default value of gcsr_flag[CSR] is 0, and we use this
>>>> + * function to set the flag to 1(SW_GCSR) or 2(HW_GCSR) if the
>>>> + * gcsr is software or hardware. It will be used by get/set_gcsr,
>>>> + * if gcsr_flag is HW we should use gcsrrd/gcsrwr to access it,
>>>> + * else use sw csr to emulate it.
>>>> + */
>>>> +static void kvm_init_gcsr_flag(void)
>>>> +{
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_CRMD);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PRMD);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_EUEN);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_MISC);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_ECFG);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_ESTAT);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_ERA);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_BADV);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_BADI);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_EENTRY);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBIDX);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBEHI);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBELO0);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBELO1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_ASID);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PGDL);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PGDH);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PWCTL0);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PWCTL1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_STLBPGSIZE);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_RVACFG);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_CPUID);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PRCFG1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PRCFG2);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_PRCFG3);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS0);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS2);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS3);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS4);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS5);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS6);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_KS7);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TMID);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TCFG);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TVAL);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_CNTC);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_LLBCTL);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRENTRY);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRBADV);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRERA);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRSAVE);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRELO0);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRELO1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBREHI);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_TLBRPRMD);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_DMWIN0);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_DMWIN1);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_DMWIN2);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_DMWIN3);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_MWPS);
>>>> +       set_gcsr_hw_flag(LOONGARCH_CSR_FWPS);
>>>> +
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IMPCTL1);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IMPCTL2);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRCTL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRINFO1);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRINFO2);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRENTRY);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRERA);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MERRSAVE);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_CTAG);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DEBUG);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DERA);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DESAVE);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PRCFG1);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PRCFG2);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PRCFG3);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PGD);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_TINTCLR);
>>>> +
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_FWPS);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_FWPC);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MWPS);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_MWPC);
>>>> +
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB0ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB0MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB0CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB0ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB1ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB1MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB1CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB1ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB2ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB2MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB2CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB2ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB3ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB3MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB3CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB3ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB4ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB4MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB4CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB4ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB5ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB5MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB5CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB5ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB6ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB6MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB6CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB6ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB7ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB7MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB7CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_DB7ASID);
>>>> +
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB0ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB0MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB0CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB0ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB1ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB1MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB1CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB1ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB2ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB2MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB2CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB2ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB3ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB3MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB3CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB3ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB4ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB4MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB4CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB4ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB5ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB5MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB5CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB5ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB6ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB6MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB6CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB6ASID);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB7ADDR);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB7MASK);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB7CTRL);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_IB7ASID);
>>>> +
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCTRL0);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR0);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCTRL1);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR1);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCTRL2);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR2);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCTRL3);
>>>> +       set_gcsr_sw_flag(LOONGARCH_CSR_PERFCNTR3);
>>>> +}
>>>> +
>>>> +static void kvm_update_vpid(struct kvm_vcpu *vcpu, int cpu)
>>>> +{
>>>> +       struct kvm_context *context;
>>>> +       unsigned long vpid;
>>>> +
>>>> +       context = per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu);
>>>> +       vpid = context->vpid_cache + 1;
>>>> +       if (!(vpid & vpid_mask)) {
>>>> +               /* finish round of 64 bit loop */
>>>> +               if (unlikely(!vpid))
>>>> +                       vpid = vpid_mask + 1;
>>>> +
>>>> +               /* vpid 0 reserved for root */
>>>> +               ++vpid;
>>>> +
>>>> +               /* start new vpid cycle */
>>>> +               kvm_flush_tlb_all();
>>>> +       }
>>>> +
>>>> +       context->vpid_cache = vpid;
>>>> +       vcpu->arch.vpid = vpid;
>>>> +}
>>>> +
>>>> +void kvm_check_vpid(struct kvm_vcpu *vcpu)
>>>> +{
>>>> +       struct kvm_context *context;
>>>> +       bool migrated;
>>>> +       unsigned long ver, old, vpid;
>>>> +       int cpu;
>>>> +
>>>> +       cpu = smp_processor_id();
>>>> +       /*
>>>> +        * Are we entering guest context on a different CPU to last time?
>>>> +        * If so, the vCPU's guest TLB state on this CPU may be stale.
>>>> +        */
>>>> +       context = per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu);
>>>> +       migrated = (vcpu->cpu != cpu);
>>>> +
>>>> +       /*
>>>> +        * Check if our vpid is of an older version
>>>> +        *
>>>> +        * We also discard the stored vpid if we've executed on
>>>> +        * another CPU, as the guest mappings may have changed without
>>>> +        * hypervisor knowledge.
>>>> +        */
>>>> +       ver = vcpu->arch.vpid & ~vpid_mask;
>>>> +       old = context->vpid_cache  & ~vpid_mask;
>>>> +       if (migrated || (ver != old)) {
>>>> +               kvm_update_vpid(vcpu, cpu);
>>>> +               trace_kvm_vpid_change(vcpu, vcpu->arch.vpid);
>>>> +               vcpu->cpu = cpu;
>>>> +       }
>>>> +
>>>> +       /* Restore GSTAT(0x50).vpid */
>>>> +       vpid = (vcpu->arch.vpid & vpid_mask) << CSR_GSTAT_GID_SHIFT;
>>>> +       change_csr_gstat(vpid_mask << CSR_GSTAT_GID_SHIFT, vpid);
>>>> +}
>>>> +
>>>> +static int kvm_loongarch_env_init(void)
>>>> +{
>>>> +       struct kvm_context *context;
>>>> +       int cpu, order;
>>>> +       void *addr;
>>>> +
>>>> +       vmcs = alloc_percpu(struct kvm_context);
>>>> +       if (!vmcs) {
>>>> +               pr_err("kvm: failed to allocate percpu kvm_context\n");
>>>> +               return -ENOMEM;
>>>> +       }
>>>> +
>>>> +       kvm_loongarch_ops = kzalloc(sizeof(*kvm_loongarch_ops), GFP_KERNEL);
>>>> +       if (!kvm_loongarch_ops) {
>>>> +               free_percpu(vmcs);
>>>> +               vmcs = NULL;
>>>> +               return -ENOMEM;
>>>> +       }
>>>> +       /*
>>>> +        * There will be problem in world switch code if there
>>>> +        * is page fault reenter, since pgd register is shared
>>>> +        * between root kernel and kvm hypervisor. World switch
>>>> +        * entry need be unmapped area, cannot be tlb mapped area.
>>>> +        * In future if hw pagetable walking is supported, or there
>>>> +        * is separate pgd registers between root kernel and kvm
>>>> +        * hypervisor, copying about world switch code will not be used.
>>>> +        */
>>>> +
>>>> +       order = get_order(kvm_vector_size + kvm_enter_guest_size);
>>>> +       addr = (void *)__get_free_pages(GFP_KERNEL, order);
>>>> +       if (!addr) {
>>>> +               free_percpu(vmcs);
>>>> +               vmcs = NULL;
>>>> +               kfree(kvm_loongarch_ops);
>>>> +               kvm_loongarch_ops = NULL;
>>>> +               return -ENOMEM;
>>>> +       }
>>>> +
>>>> +       memcpy(addr, kvm_vector_entry, kvm_vector_size);
>>>> +       memcpy(addr + kvm_vector_size, kvm_enter_guest, kvm_enter_guest_size);
>>> Why memcpy? In our internal repo, we use kvm_vector_entry and
>>> kvm_enter_guest directly. The long comments above make me nervous
>>> because Loongson-3A6000 already supports hardware pagetable walker.
>>>
>>> Huacai
>> As mentioned in the comments, it need not this memcpy if hardware page
>> walk is supported in 3A6000.
> But why in our internal repo we don't use memcpy() but kvm can still
> work on Loongson-3A5000?
>
> Huacai
Because in our internal repo, the KVM is build along with the linux 
kernel, however, this KVM patch series is build in module.

Thanks
Tianrui Zhao
>
>> Thanks
>> Tianrui Zhao
>>>> +       flush_icache_range((unsigned long)addr, (unsigned long)addr +
>>>> +                               kvm_vector_size + kvm_enter_guest_size);
>>>> +       kvm_loongarch_ops->guest_eentry = addr;
>>>> +       kvm_loongarch_ops->enter_guest = addr + kvm_vector_size;
>>>> +       kvm_loongarch_ops->page_order = order;
>>>> +
>>>> +       vpid_mask = read_csr_gstat();
>>>> +       vpid_mask = (vpid_mask & CSR_GSTAT_GIDBIT) >> CSR_GSTAT_GIDBIT_SHIFT;
>>>> +       if (vpid_mask)
>>>> +               vpid_mask = GENMASK(vpid_mask - 1, 0);
>>>> +
>>>> +       for_each_possible_cpu(cpu) {
>>>> +               context = per_cpu_ptr(vmcs, cpu);
>>>> +               context->vpid_cache = vpid_mask + 1;
>>>> +               context->last_vcpu = NULL;
>>>> +       }
>>>> +
>>>> +       kvm_init_fault();
>>>> +       kvm_init_gcsr_flag();
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>>>> +static void kvm_loongarch_env_exit(void)
>>>> +{
>>>> +       unsigned long addr;
>>>> +
>>>> +       if (vmcs)
>>>> +               free_percpu(vmcs);
>>>> +
>>>> +       if (kvm_loongarch_ops) {
>>>> +               if (kvm_loongarch_ops->guest_eentry) {
>>>> +                       addr = (unsigned long)kvm_loongarch_ops->guest_eentry;
>>>> +                       free_pages(addr, kvm_loongarch_ops->page_order);
>>>> +               }
>>>> +               kfree(kvm_loongarch_ops);
>>>> +       }
>>>> +}
>>>> +
>>>> +static int kvm_loongarch_init(void)
>>>> +{
>>>> +       int r;
>>>> +
>>>> +       if (!cpu_has_lvz) {
>>>> +               kvm_info("hardware virtualization not available\n");
>>>> +               return -ENODEV;
>>>> +       }
>>>> +       r = kvm_loongarch_env_init();
>>>> +       if (r)
>>>> +               return r;
>>>> +
>>>> +       return kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
>>>> +}
>>>> +
>>>> +static void kvm_loongarch_exit(void)
>>>> +{
>>>> +       kvm_exit();
>>>> +       kvm_loongarch_env_exit();
>>>> +}
>>>> +
>>>> +module_init(kvm_loongarch_init);
>>>> +module_exit(kvm_loongarch_exit);
>>>> +
>>>> +#ifdef MODULE
>>>> +static const struct cpu_feature loongarch_kvm_feature[] = {
>>>> +       { .feature = cpu_feature(LOONGARCH_LVZ) },
>>>> +       {},
>>>> +};
>>>> +MODULE_DEVICE_TABLE(cpu, loongarch_kvm_feature);
>>>> +#endif
>>>> --
>>>> 2.39.1
>>>>
>>