From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72B4CC433E0 for ; Tue, 16 Mar 2021 13:44:20 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id E233165053 for ; Tue, 16 Mar 2021 13:44:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E233165053 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 87DE04B5D1; Tue, 16 Mar 2021 09:44:19 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4h7Mz7VxmE4d; Tue, 16 Mar 2021 09:44:18 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6FA854B5DD; Tue, 16 Mar 2021 09:44:18 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 6D33A4B41A for ; Tue, 16 Mar 2021 09:44:17 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rKMNf8IYSSfT for ; Tue, 16 Mar 2021 09:44:16 -0400 (EDT) Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id D6C9E4B5D9 for ; Tue, 16 Mar 2021 09:44:14 -0400 (EDT) Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4F0DwQ3jhnzNngl; Tue, 16 Mar 2021 21:41:42 +0800 (CST) Received: from DESKTOP-5IS4806.china.huawei.com (10.174.184.42) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Tue, 16 Mar 2021 21:43:56 +0800 From: Keqian Zhu To: , , , , Will Deacon , Marc Zyngier Subject: [RFC PATCH v2 2/2] kvm/arm64: Try stage2 block mapping for host device MMIO Date: Tue, 16 Mar 2021 21:43:38 +0800 Message-ID: <20210316134338.18052-3-zhukeqian1@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20210316134338.18052-1-zhukeqian1@huawei.com> References: <20210316134338.18052-1-zhukeqian1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.184.42] X-CFilter-Loop: Reflected Cc: Catalin Marinas , lushenming@huawei.com X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu The MMIO region of a device maybe huge (GB level), try to use block mapping in stage2 to speedup both map and unmap. Compared to normal memory mapping, we should consider two more points when try block mapping for MMIO region: 1. For normal memory mapping, the PA(host physical address) and HVA have same alignment within PUD_SIZE or PMD_SIZE when we use the HVA to request hugepage, so we don't need to consider PA alignment when verifing block mapping. But for device memory mapping, the PA and HVA may have different alignment. 2. For normal memory mapping, we are sure hugepage size properly fit into vma, so we don't check whether the mapping size exceeds the boundary of vma. But for device memory mapping, we should pay attention to this. This adds device_rough_page_shift() to check these two points when selecting block mapping size. Signed-off-by: Keqian Zhu --- Mainly for RFC, not fully tested. I will fully test it when the code logic is well accepted. --- arch/arm64/kvm/mmu.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c59af5ca01b0..224aa15eb4d9 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -624,6 +624,36 @@ static void kvm_send_hwpoison_signal(unsigned long address, short lsb) send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, current); } +/* + * Find a mapping size that properly insides the intersection of vma and + * memslot. And hva and pa have the same alignment to this mapping size. + * It's rough because there are still other restrictions, which will be + * checked by the following fault_supports_stage2_huge_mapping(). + */ +static short device_rough_page_shift(struct kvm_memory_slot *memslot, + struct vm_area_struct *vma, + unsigned long hva) +{ + size_t size = memslot->npages * PAGE_SIZE; + hva_t sec_start = max(memslot->userspace_addr, vma->vm_start); + hva_t sec_end = min(memslot->userspace_addr + size, vma->vm_end); + phys_addr_t pa = (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start); + +#ifndef __PAGETABLE_PMD_FOLDED + if ((hva & (PUD_SIZE - 1)) == (pa & (PUD_SIZE - 1)) && + ALIGN_DOWN(hva, PUD_SIZE) >= sec_start && + ALIGN(hva, PUD_SIZE) <= sec_end) + return PUD_SHIFT; +#endif + + if ((hva & (PMD_SIZE - 1)) == (pa & (PMD_SIZE - 1)) && + ALIGN_DOWN(hva, PMD_SIZE) >= sec_start && + ALIGN(hva, PMD_SIZE) <= sec_end) + return PMD_SHIFT; + + return PAGE_SHIFT; +} + static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot, unsigned long hva, unsigned long map_size) @@ -769,7 +799,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, return -EFAULT; } - /* Let's check if we will get back a huge page backed by hugetlbfs */ + /* + * Let's check if we will get back a huge page backed by hugetlbfs, or + * get block mapping for device MMIO region. + */ mmap_read_lock(current->mm); vma = find_vma_intersection(current->mm, hva, hva + 1); if (unlikely(!vma)) { @@ -780,11 +813,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (is_vm_hugetlb_page(vma)) vma_shift = huge_page_shift(hstate_vma(vma)); + else if (vma->vm_flags & VM_PFNMAP) + vma_shift = device_rough_page_shift(memslot, vma, hva); else vma_shift = PAGE_SHIFT; - if (logging_active || - (vma->vm_flags & VM_PFNMAP)) { + if (logging_active) { force_pte = true; vma_shift = PAGE_SHIFT; } @@ -855,7 +889,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (kvm_is_device_pfn(pfn)) { device = true; - force_pte = true; + force_pte = (vma_pagesize == PAGE_SIZE); } else if (logging_active && !write_fault) { /* * Only actually map the page as writable if this was a write -- 2.19.1 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm