Subject: Re: [PATCH v2 06/29] LoongArch: KVM: Implement vcpu create and
 destroy interface
To:     Paolo Bonzini <pbonzini@redhat.com>
References: <20230220065735.1282809-1-zhaotianrui@loongson.cn>
 <20230220065735.1282809-7-zhaotianrui@loongson.cn>
 <cbd95763-ec38-63f7-89bf-c8b01aa7df77@redhat.com>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, 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
From:   Tianrui Zhao <zhaotianrui@loongson.cn>
Message-ID: <abfa3fbc-e234-d0ab-ec35-90d9c251bf79@loongson.cn>
Date:   Wed, 22 Feb 2023 09:52:23 +0800
User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
MIME-Version: 1.0
In-Reply-To: <cbd95763-ec38-63f7-89bf-c8b01aa7df77@redhat.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2023年02月21日 01:53, Paolo Bonzini 写道:
> On 2/20/23 07:57, Tianrui Zhao wrote:
>> +    vcpu->arch.guest_eentry = (unsigned long)kvm_context->kvm_eentry;
>> +    vcpu->arch.vcpu_run = kvm_context->kvm_enter_guest;
>> +    vcpu->arch.handle_exit = _kvm_handle_exit;
>
> Here as well, whatever is constant must not be stored in struct 
> kvm_arch_vcpu.
>
> Paolo

Thanks,  we use this in vcpu_arch because the vcpu_arch is used as 
argument in switch.S' methods, we can quickly access the guest_eentry 
and handle_exit by using the  KVM_ARCH_GEENTRY, KVM_ARCH_HANDLE_EXIT 
offsets. If we change to global variable ,  we should relocate it in 
switch.S and may lead  to lower accessing speed.