From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: Summary of LPC guest MSI discussion in Santa Fe Date: Thu, 10 Nov 2016 15:52:00 +0100 Message-ID: <20161110145200.GD2078@8bytes.org> References: <20161109170326.GG17771@arm.com> <582371FB.2040808@redhat.com> <20161109192303.GD15676@cbox> <20161109203145.GO17771@arm.com> <20161109151709.74927f83@t450s.home> <20161109222522.GS17771@arm.com> <20161109162458.39594fdb@t450s.home> <20161109233847.GT17771@arm.com> <20161109165957.62c1eb61@t450s.home> <83b6440a-31eb-c1b4-642c-a4c311f37ef2@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <83b6440a-31eb-c1b4-642c-a4c311f37ef2@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Auger Eric Cc: Alex Williamson , Will Deacon , drjones@redhat.com, jason@lakedaemon.net, kvm@vger.kernel.org, marc.zyngier@arm.com, benh@kernel.crashing.org, punit.agrawal@arm.com, linux-kernel@vger.kernel.org, arnd@arndb.de, diana.craciun@nxp.com, iommu@lists.linux-foundation.org, pranav.sawargaonkar@gmail.com, Don Dutile , linux-arm-kernel@lists.infradead.org, jcm@redhat.com, tglx@linutronix.de, robin.murphy@arm.com, dwmw@amazon.co.uk, Christoffer Dall , eric.auger.pro@gmail.com List-Id: iommu@lists.linux-foundation.org On Thu, Nov 10, 2016 at 01:14:42AM +0100, Auger Eric wrote: > Besides above problematic, I started to prototype the sysfs API. A first > issue I face is the reserved regions become global to the iommu instead > of characterizing the iommu_domain, ie. the "reserved_regions" attribute > file sits below an iommu instance (~ > /sys/class/iommu/dmar0/intel-iommu/reserved_regions || > /sys/class/iommu/arm-smmu0/arm-smmu/reserved_regions). > > MSI reserved window can be considered global to the IOMMU. However PCIe > host bridge P2P regions rather are per iommu-domain. > > Do you confirm the attribute file should contain both global reserved > regions and all per iommu_domain reserved regions? > > Thoughts? This information is best attached to the sysfs-representation of iommu-groups. The file should then contain the superset of all reserved regions of the devices the group contains. This makes it usable later to also describe RMRR/Unity-mapped regions on x86 there and make them assignable to guests as well. Joerg