From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH] vfio/iommu_type1: report the IOMMU aperture info Date: Thu, 30 Nov 2017 15:16:03 +0100 Message-ID: <7cf3e03e-e9b4-0e27-098b-3bc391abcf96@linux.vnet.ibm.com> References: <1512041678-4563-1-git-send-email-pmorel@linux.vnet.ibm.com> <1ad1aff9-1651-d1a9-cd1b-07bfd7dd0817@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Cc: "cohuck@redhat.com" , "borntraeger@de.ibm.com" , "zyimin@linux.vnet.ibm.com" , "pasic@linux.vnet.ibm.com" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: Jean-Philippe Brucker , "alex.williamson@redhat.com" Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:40158 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751099AbdK3OQM (ORCPT ); Thu, 30 Nov 2017 09:16:12 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vAUEFTw5110321 for ; Thu, 30 Nov 2017 09:16:12 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ejk75sjcn-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 30 Nov 2017 09:16:10 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 30 Nov 2017 14:16:07 -0000 In-Reply-To: <1ad1aff9-1651-d1a9-cd1b-07bfd7dd0817@arm.com> Content-Language: en-US Sender: kvm-owner@vger.kernel.org List-ID: On 30/11/2017 13:57, Jean-Philippe Brucker wrote: > Hello, > > On 30/11/17 11:34, Pierre Morel wrote: > [...] >> +/** >> + * vfio_get_aperture - report minimal aperture of a vfio_iommu >> + * @iommu: the current vfio_iommu >> + * @start: a pointer to the aperture start >> + * @end : a pointer to the aperture end >> + * >> + * This function iterate on the domains using the given vfio_iommu >> + * and restrict the aperture to the minimal aperture common >> + * to all domains sharing this vfio_iommu. >> + */ >> +static void vfio_get_aperture(struct vfio_iommu *iommu, uint64_t *start, >> + uint64_t *end) >> +{ >> + struct iommu_domain_geometry geometry; >> + struct vfio_domain *domain; >> + >> + *start = 0; >> + *end = U64_MAX; > > I wonder if the default values should also reflect what the VFIO > implementation actually supports. Looking at vfio_dma_do_map, a 32-bit > host will reject any iova greater than 32 bits. In addition, > vfio_dma_do_unmap doesn't support unmapping the last page of a 64-bit > address space (existing IOMMUs would probably reject map requests with > IOVA > 52 bits anyway, but if they don't report a domain aperture, VFIO > can't guess it). > > I think it's convenient to use VFIO_IOMMU_UNMAP_DMA on the full address > space when an unmap-all is needed, maybe we could provide default aperture > values that help doing this? (~0U for 32-bit and (~0ULL - PAGE_SIZE) for > 64-bit) > > Thanks, > Jean > Thanks, I will take care of this. Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany