From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8C161ED3 for ; Tue, 21 Feb 2023 03:02:34 +0000 (UTC) Received: from loongson.cn (unknown [10.20.42.120]) by gateway (Coremail) with SMTP id _____8Dx_5dDNPRjiQYDAA--.652S3; Tue, 21 Feb 2023 11:02:27 +0800 (CST) Received: from [10.20.42.120] (unknown [10.20.42.120]) by localhost.localdomain (Coremail) with SMTP id AQAAf8BxsOQwNPRjrH83AA--.783S3; Tue, 21 Feb 2023 11:02:09 +0800 (CST) Subject: Re: [PATCH v2 02/29] LoongArch: KVM: Implement kvm module related interface To: Paolo Bonzini References: <20230220065735.1282809-1-zhaotianrui@loongson.cn> <20230220065735.1282809-3-zhaotianrui@loongson.cn> Cc: Huacai Chen , WANG Xuerui , Greg Kroah-Hartman , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Jens Axboe , Mark Brown , Alex Deucher , Oliver Upton , maobibo@loongson.cn From: Tianrui Zhao Message-ID: <708f97e8-0501-a4d4-2c33-7f4c41339d6b@loongson.cn> Date: Tue, 21 Feb 2023 11:02:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:AQAAf8BxsOQwNPRjrH83AA--.783S3 X-CM-SenderInfo: p2kd03xldq233l6o00pqjv00gofq/ X-Coremail-Antispam: 1Uk129KBjvJXoW7tw1UuF45KFWfCrykXw4xWFg_yoW8XF4Upa 4DCFn5Ar4UJFyfXwn0ya1vq3WFq3ykK3W2k3W0k3WYk3srurna9rs7Jr4j9F97Zrn3AF4v va1YgrsxXrn0qFJanT9S1TB71UUUUj7qnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bqkYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l n4kS14v26r126r1DM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6x ACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1q6rW5McIj6I8E 87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0V AS07AlzVAYIcxG8wCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCF s4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUAVWUtwC20s026c02F40E14v26r1j6r18MI 8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41l IxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIx AIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2 jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jz5lbUUUUU= 在 2023年02月21日 01:46, Paolo Bonzini 写道: > On 2/20/23 07:57, Tianrui Zhao wrote: >> + order = get_order(kvm_vector_size + kvm_enter_guest_size); >> + addr = (void *)__get_free_pages(GFP_KERNEL, order); >> + if (!addr) { >> + free_percpu(vmcs); >> + 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); >> + >> + 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_mask = vpid_mask; >> + context->vpid_cache = context->vpid_mask + 1; >> + context->last_vcpu = NULL; >> + context->kvm_eentry = addr; >> + context->kvm_enter_guest = addr + kvm_vector_size; >> + context->page_order = order; >> + } > > A lot of these variables are constant across all pCPUs, any reason to > have them in a per-CPU variable? Likewise, since they are all the > same as the constant global vmcs variable, why make them part of > struct kvm_context instead of just making them globals? Ok thanks, it is more appropriate to use global variables to save those information. Thanks Tianrui Zhao > > Also, why does the world switch code need a copy? > > Paolo