From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auger Eric Subject: Re: [PATCH v6 05/22] iommu: Introduce cache_invalidate API Date: Fri, 22 Mar 2019 08:58:54 +0100 Message-ID: <4464787c-7300-a2cf-51a2-e77570dc219b@redhat.com> References: <20190317172232.1068-1-eric.auger@redhat.com> <20190317172232.1068-6-eric.auger@redhat.com> <20190320093727.45a86866@jacob-builder> <7ae1df77-18d0-0993-8dab-6af3a4474b42@arm.com> <109c3520-dd26-3c0b-35d1-48b169fea982@arm.com> <41173658-dde0-6e58-90ed-65cff2b1dd1c@redhat.com> <20190321151005.07374be0@jacob-builder> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190321151005.07374be0@jacob-builder> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jacob Pan Cc: Jean-Philippe Brucker , yi.l.liu@linux.intel.com, kevin.tian@intel.com, vincent.stehle@arm.com, ashok.raj@intel.com, kvm@vger.kernel.org, peter.maydell@linaro.org, marc.zyngier@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, christoffer.dall@arm.com, alex.williamson@redhat.com, robin.murphy@arm.com, kvmarm@lists.cs.columbia.edu, eric.auger.pro@gmail.com List-Id: iommu@lists.linux-foundation.org Hi Jacob, On 3/21/19 11:10 PM, Jacob Pan wrote: > On Thu, 21 Mar 2019 15:32:45 +0100 > Auger Eric wrote: > >> Hi jean, Jacob, >> >> On 3/21/19 3:13 PM, Jean-Philippe Brucker wrote: >>> On 21/03/2019 13:54, Auger Eric wrote: >>>> Hi Jacob, Jean-Philippe, >>>> >>>> On 3/20/19 5:50 PM, Jean-Philippe Brucker wrote: >>>>> On 20/03/2019 16:37, Jacob Pan wrote: >>>>> [...] >>>>>>> +struct iommu_inv_addr_info { >>>>>>> +#define IOMMU_INV_ADDR_FLAGS_PASID (1 << 0) >>>>>>> +#define IOMMU_INV_ADDR_FLAGS_ARCHID (1 << 1) >>>>>>> +#define IOMMU_INV_ADDR_FLAGS_LEAF (1 << 2) >>>>>>> + __u32 flags; >>>>>>> + __u32 archid; >>>>>>> + __u64 pasid; >>>>>>> + __u64 addr; >>>>>>> + __u64 granule_size; >>>>>>> + __u64 nb_granules; >>>>>>> +}; >>>>>>> + >>>>>>> +/** >>>>>>> + * First level/stage invalidation information >>>>>>> + * @cache: bitfield that allows to select which caches to >>>>>>> invalidate >>>>>>> + * @granularity: defines the lowest granularity used for the >>>>>>> invalidation: >>>>>>> + * domain > pasid > addr >>>>>>> + * >>>>>>> + * Not all the combinations of cache/granularity make sense: >>>>>>> + * >>>>>>> + * type | DEV_IOTLB | IOTLB | >>>>>>> PASID | >>>>>>> + * granularity | | | >>>>>>> cache | >>>>>>> + * >>>>>>> -------------+---------------+---------------+---------------+ >>>>>>> + * DOMAIN | N/A | Y | >>>>>>> Y | >>>>>>> + * PASID | Y | Y | >>>>>>> Y | >>>>>>> + * ADDR | Y | Y | >>>>>>> N/A | >>>>>>> + */ >>>>>>> +struct iommu_cache_invalidate_info { >>>>>>> +#define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1 >>>>>>> + __u32 version; >>>>>>> +/* IOMMU paging structure cache */ >>>>>>> +#define IOMMU_CACHE_INV_TYPE_IOTLB (1 << 0) /* IOMMU >>>>>>> IOTLB */ +#define IOMMU_CACHE_INV_TYPE_DEV_IOTLB (1 << >>>>>>> 1) /* Device IOTLB */ +#define >>>>>>> IOMMU_CACHE_INV_TYPE_PASID (1 << 2) /* PASID cache */ >>>>>> Just a clarification, this used to be an enum. You do intend to >>>>>> issue a single invalidation request on multiple cache types? >>>>>> Perhaps for virtio-IOMMU? I only see a single cache type in your >>>>>> patch #14. For VT-d we plan to issue one cache type at a time >>>>>> for now. So this format works for us. >>>>> >>>>> Yes for virtio-iommu I'd like as little overhead as possible, >>>>> which means a single invalidation message to hit both IOTLB and >>>>> ATC at once, and the ability to specify multiple pages with >>>>> @nb_granules. >>>> The original request/explanation from Jean-Philippe can be found >>>> here: https://lkml.org/lkml/2019/1/28/1497 >>>> >>>>> >>>>>> However, if multiple cache types are issued in a single >>>>>> invalidation. They must share a single granularity, not all >>>>>> combinations are valid. e.g. dev IOTLB does not support domain >>>>>> granularity. Just a reminder, not an issue. Driver could filter >>>>>> out invalid combinations. >>>> Sure I will add a comment about this restriction. >>>>> >>>>> Agreed. Even the core could filter out invalid combinations based >>>>> on the table above: IOTLB and domain granularity are N/A. >>>> I don't get this sentence. What about vtd IOTLB domain-selective >>>> invalidation: >>> >>> My mistake: I meant dev-IOTLB and domain granularity are N/A >> >> Ah OK, no worries. >> >> How do we proceed further with those user APIs? Besides the comment to >> be added above and previous suggestion from Jean ("Invalidations by >> @granularity use field ...), have we reached a consensus now on: >> >> - attach/detach_pasid_table >> - cache_invalidate >> - fault data and fault report API? >> > These APIs are sufficient for today's VT-d use and leave enough space > for extension. E.g. new fault reasons. > > I have cherry picked the above APIs from your patchset to enable VT-d > nested translation. Going forward, I will reuse these until they get > merged. OK thanks! Eric > >> If not, please let me know. >> >> Thanks >> >> Eric >> >> >>> >>> Thanks, >>> Jean >>> >>>> " >>>> • IOTLB entries caching mappings associated with the specified >>>> domain-id are invalidated. >>>> • Paging-structure-cache entries caching mappings associated with >>>> the specified domain-id are invalidated. >>>> " >>>> >>>> Thanks >>>> >>>> Eric >>>> >>>>> >>>>> Thanks, >>>>> Jean >>>>> >>>>>> >>>>>>> + __u8 cache; >>>>>>> + __u8 granularity; >>>>>>> + __u8 padding[2]; >>>>>>> + union { >>>>>>> + __u64 pasid; >>>>>>> + struct iommu_inv_addr_info addr_info; >>>>>>> + }; >>>>>>> +}; >>>>>>> + >>>>>>> + >>>>>>> #endif /* _UAPI_IOMMU_H */ >>>>>> >>>>>> [Jacob Pan] >>>>>> _______________________________________________ >>>>>> iommu mailing list >>>>>> iommu@lists.linux-foundation.org >>>>>> https://lists.linuxfoundation.org/mailman/listinfo/iommu >>>>>> >>>>> >>>> _______________________________________________ >>>> iommu mailing list >>>> iommu@lists.linux-foundation.org >>>> https://lists.linuxfoundation.org/mailman/listinfo/iommu >>>> >>> > > [Jacob Pan] >