From patchwork Tue Mar 16 13:43:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: zhukeqian X-Patchwork-Id: 12142233 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=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 1EE22C433E0 for ; Tue, 16 Mar 2021 13:46:50 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A29F465053 for ; Tue, 16 Mar 2021 13:46:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A29F465053 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VRlulrPwLXlnfip4QAWDqWOwydVaF90trO1DcALWz7k=; b=WVk1NebTLo8cf6UojOCX/TJ36 FMVo3vSJxAUbtnXu1ielZ8zVpxU226k00F1rdhF/RZvJwgTLqOCFUku6D9BXJPowo3NwXQPfrToQm HvCUtM1wozlWfP2fYtePgKzT80ms663ND57k7UfL2h3I0bIgPMW0XLTHL4dRgSHbM+/Up7zH8Y+lD 3/zEaEJt5gM2z3hZETM8EcVh5nUJYQa410/3jbJAVLeNGlJHnquvJx30yNUCXFZZqiSjoLz4xGQm4 WydU2ztcEg6KmjisAddL1QAZbmcT4SwdEaAWrZiVksju4CEabZqQrZsKS9FEPWR2jpt6HqoJxdPk3 Pwtze8W6A==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMA0s-000rWE-3G; Tue, 16 Mar 2021 13:45:34 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lM9zU-000rFg-Oy for linux-arm-kernel@lists.infradead.org; Tue, 16 Mar 2021 13:44:13 +0000 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 CC: Catalin Marinas , Mark Rutland , James Morse , Suzuki K Poulose , Julien Thierry , , , , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_134412_196243_A7CE84AE X-CRM114-Status: GOOD ( 18.96 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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