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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-H5ti7L+QXJ=boK8aKNwt74Pvn1-vm71B9Bymi+2zXXzHw@mail.gmail.com>
 <525aa9e2-1ebc-6c49-55ef-9f3c7d18d3e0@loongson.cn>
 <CAAhV-H7wB_N0nFm1JMhKJR=8NAuDR3XNC6NfeZis0VhDECAUjg@mail.gmail.com>
 <b11389ee-7740-7911-2e57-75edadade703@loongson.cn>
 <CAAhV-H5bmk5jF8Rbso7uUc2-pUvduwdJOoD2Gj_krJZoZ+y1ag@mail.gmail.com>
 <8e23325a-b4d3-db80-7d65-ebadcd3ef5a9@loongson.cn>
 <CAAhV-H7cKTqAhaDrnrLMHfS0Y0pzwUugdwX0oK2hj7i06Q6_tg@mail.gmail.com>
From:   zhaotianrui <zhaotianrui@loongson.cn>
Message-ID: <a3589841-e093-e19a-3f41-94da04344a20@loongson.cn>
Date:   Mon, 18 Sep 2023 14:25:05 +0800
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在 2023/9/18 下午12:03, Huacai Chen 写道:
> On Mon, Sep 18, 2023 at 11:20 AM zhaotianrui <zhaotianrui@loongson.cn> wrote:
>>
>> 在 2023/9/18 上午11:12, Huacai Chen 写道:
>>> On Mon, Sep 18, 2023 at 11:08 AM zhaotianrui <zhaotianrui@loongson.cn> wrote:
>>>> 在 2023/9/18 上午9:45, Huacai Chen 写道:
>>>>> On Mon, Sep 18, 2023 at 9:21 AM zhaotianrui <zhaotianrui@loongson.cn> wrote:
>>>>>> 在 2023/9/16 下午4:51, 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);
>>>>>>> FWPS and MWPS are both HW CSR and SW CSR?
>>>>>>>
>>>>>>> Huacai
>>>>>> The FWPC and MWPC should be SW GCSR, FWPS and MWPS should be HW GCSR, it
>>>>>> is my mistake.
>>>>> But in user manual vol 3, section 1.5, FWPC/FWPS/MWPC/MWPS are all HW
>>>>> GCSR, while DBxxxx and IBxxxx are SW GCSR.
>>>> Ok, It is my misunderstanding, as the FWPC and MWPC can control guest
>>>> debug register numbers, but I know they are all HW GCSR when I look up
>>>> the manual again.
>>> So these lines can be removed?
>>>
>>>           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);
>>>
>>> And add FWPC/MWPC to hw list?
> Can you discuss more with our hw engineers? I found in section 1.8:
> PGD, TINTCLR, PRCFG1~3 are all HW GCSR.
If guest can access hw CSR directly and do not cause a exception, it 
means hw GCSR. on the other hand, if cause a exception to return to KVM 
to emulate it by software, it means SW GCSR. And I re-check the PGD, 
TINTCLR, PRCFG1~3 CSR, they should be hw GCSR.

Thanks
Tianrui Zhao
>
> Huacai
>
>>> Huacai
>> Yes, It is.
>>
>> Thanks
>> Tianrui Zhao
>>>> Thanks
>>>> Tianrui Zhao
>>>>> Huacai
>>>>>
>>>>>> Thanks
>>>>>> Tianrui Zhao
>>>>>>>> +
>>>>>>>> +       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);
>>>>>>>> +       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
>>>>>>>>
>>