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([2001:b07:6468:f312:7822:aa18:a9d8:39ab]) by smtp.gmail.com with ESMTPSA id t198sm4983601wmt.2.2019.06.20.01.35.28 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Thu, 20 Jun 2019 01:35:28 -0700 (PDT) To: Peter Xu , Auger Eric References: <1560934185-14152-1-git-send-email-yan.y.zhao@intel.com> <39c4c32b-e34a-8d8f-abbc-ab346ec5bed7@redhat.com> <20190620040230.GB9073@xz-x1> From: Paolo Bonzini Message-ID: <6829b139-3eab-449e-04d6-07f1e381316d@redhat.com> Date: Thu, 20 Jun 2019 10:35:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190620040230.GB9073@xz-x1> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.221.66 Subject: Re: [Qemu-devel] [PATCH] memory: do not do out of bound notification X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Yan Zhao , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 20/06/19 06:02, Peter Xu wrote: > Seems workable, to be explicit - we can even cut it into chunks with > different size to be efficient. Yes, this is not hard (completely untested): diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 44b1231157..541538bc6c 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -3388,39 +3388,34 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n) } assert(start <= end); - size = end - start; + while (end > start) { + size = end - start; + /* Only keep the lowest bit of either size or start. */ + size = MIN(size & -size, start & -start); + /* Should not happen, but limit to address width too just in case */ + size = MIN(size, 1ULL << s->aw_bits); - if (ctpop64(size) != 1) { - /* - * This size cannot format a correct mask. Let's enlarge it to - * suite the minimum available mask. - */ - int n = 64 - clz64(size); - if (n > s->aw_bits) { - /* should not happen, but in case it happens, limit it */ - n = s->aw_bits; - } - size = 1ULL << n; - } + assert((start & (size - 1)) == 0); - entry.target_as = &address_space_memory; - /* Adjust iova for the size */ - entry.iova = n->start & ~(size - 1); - /* This field is meaningless for unmap */ - entry.translated_addr = 0; - entry.perm = IOMMU_NONE; - entry.addr_mask = size - 1; + entry.target_as = &address_space_memory; + entry.iova = start; + /* This field is meaningless for unmap */ + entry.translated_addr = 0; + entry.perm = IOMMU_NONE; + entry.addr_mask = size - 1; - trace_vtd_as_unmap_whole(pci_bus_num(as->bus), - VTD_PCI_SLOT(as->devfn), - VTD_PCI_FUNC(as->devfn), - entry.iova, size); + trace_vtd_as_unmap_whole(pci_bus_num(as->bus), + VTD_PCI_SLOT(as->devfn), + VTD_PCI_FUNC(as->devfn), + entry.iova, size); - map.iova = entry.iova; - map.size = entry.addr_mask; - iova_tree_remove(as->iova_tree, &map); + map.iova = entry.iova; + map.size = entry.addr_mask; + iova_tree_remove(as->iova_tree, &map); - memory_region_notify_one(n, &entry); + memory_region_notify_one(n, &entry); + start += size; + } } static void vtd_address_space_unmap_all(IntelIOMMUState *s) Yan, if something like this works for you, let me know and I will submit it as a proper patch. Paolo