From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 9B9A8C282C0 for ; Fri, 25 Jan 2019 17:51:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6836F218A2 for ; Fri, 25 Jan 2019 17:51:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729477AbfAYRvR (ORCPT ); Fri, 25 Jan 2019 12:51:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51724 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729454AbfAYRvQ (ORCPT ); Fri, 25 Jan 2019 12:51:16 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D5D5E1487FC; Fri, 25 Jan 2019 17:51:15 +0000 (UTC) Received: from [10.36.116.52] (ovpn-116-52.ams2.redhat.com [10.36.116.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AAFA2183E9; Fri, 25 Jan 2019 17:51:11 +0000 (UTC) Subject: Re: [RFC v3 03/21] iommu: Introduce bind_guest_msi To: Alex Williamson Cc: eric.auger.pro@gmail.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, joro@8bytes.org, jacob.jun.pan@linux.intel.com, yi.l.liu@linux.intel.com, jean-philippe.brucker@arm.com, will.deacon@arm.com, robin.murphy@arm.com, kevin.tian@intel.com, ashok.raj@intel.com, marc.zyngier@arm.com, christoffer.dall@arm.com, peter.maydell@linaro.org References: <20190108102633.17482-1-eric.auger@redhat.com> <20190108102633.17482-4-eric.auger@redhat.com> <20190111154419.502b3850@x1.home> From: Auger Eric Message-ID: <6969a418-bd9c-7ae9-1790-fece4a42e81e@redhat.com> Date: Fri, 25 Jan 2019 18:51:09 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190111154419.502b3850@x1.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 25 Jan 2019 17:51:16 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alex, On 1/11/19 11:44 PM, Alex Williamson wrote: > On Tue, 8 Jan 2019 11:26:15 +0100 > Eric Auger wrote: > >> On ARM, MSI are translated by the SMMU. An IOVA is allocated >> for each MSI doorbell. If both the host and the guest are exposed >> with SMMUs, we end up with 2 different IOVAs allocated by each. >> guest allocates an IOVA (gIOVA) to map onto the guest MSI >> doorbell (gDB). The Host allocates another IOVA (hIOVA) to map >> onto the physical doorbell (hDB). >> >> So we end up with 2 untied mappings: >> S1 S2 >> gIOVA -> gDB >> hIOVA -> gDB > ^^^ hDB right! > >> Currently the PCI device is programmed by the host with hIOVA >> as MSI doorbell. So this does not work. >> >> This patch introduces an API to pass gIOVA/gDB to the host so >> that gIOVA can be reused by the host instead of re-allocating >> a new IOVA. So the goal is to create the following nested mapping: >> >> S1 S2 >> gIOVA -> gDB -> hDB >> >> and program the PCI device with gIOVA MSI doorbell. >> >> Signed-off-by: Eric Auger >> >> --- >> >> v2 -> v3: >> - add a struct device handle >> --- >> drivers/iommu/iommu.c | 10 ++++++++++ >> include/linux/iommu.h | 13 +++++++++++++ >> include/uapi/linux/iommu.h | 6 ++++++ >> 3 files changed, 29 insertions(+) >> >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index b2e248770508..ea11442e7054 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -1431,6 +1431,16 @@ static void __iommu_detach_device(struct iommu_domain *domain, >> trace_detach_device_from_domain(dev); >> } >> >> +int iommu_bind_guest_msi(struct iommu_domain *domain, struct device *dev, >> + struct iommu_guest_msi_binding *binding) >> +{ >> + if (unlikely(!domain->ops->bind_guest_msi)) >> + return -ENODEV; >> + >> + return domain->ops->bind_guest_msi(domain, dev, binding); >> +} >> +EXPORT_SYMBOL_GPL(iommu_bind_guest_msi); >> + >> void iommu_detach_device(struct iommu_domain *domain, struct device *dev) >> { >> struct iommu_group *group; >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 96d59886f230..244c1a3d5989 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -235,6 +235,9 @@ struct iommu_ops { >> int (*cache_invalidate)(struct iommu_domain *domain, struct device *dev, >> struct iommu_cache_invalidate_info *inv_info); >> >> + int (*bind_guest_msi)(struct iommu_domain *domain, struct device *dev, >> + struct iommu_guest_msi_binding *binding); >> + >> unsigned long pgsize_bitmap; >> }; >> >> @@ -301,6 +304,9 @@ extern int iommu_set_pasid_table(struct iommu_domain *domain, >> extern int iommu_cache_invalidate(struct iommu_domain *domain, >> struct device *dev, >> struct iommu_cache_invalidate_info *inv_info); >> +extern int iommu_bind_guest_msi(struct iommu_domain *domain, struct device *dev, >> + struct iommu_guest_msi_binding *binding); >> + >> extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev); >> extern struct iommu_domain *iommu_get_dma_domain(struct device *dev); >> extern int iommu_map(struct iommu_domain *domain, unsigned long iova, >> @@ -724,6 +730,13 @@ iommu_cache_invalidate(struct iommu_domain *domain, >> return -ENODEV; >> } >> >> +static inline >> +int iommu_bind_guest_msi(struct iommu_domain *domain, struct device *dev, >> + struct iommu_guest_msi_binding *binding) >> +{ >> + return -ENODEV; >> +} >> + >> #endif /* CONFIG_IOMMU_API */ >> >> #ifdef CONFIG_IOMMU_DEBUGFS >> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h >> index 4605f5cfac84..f28cd9a1aa96 100644 >> --- a/include/uapi/linux/iommu.h >> +++ b/include/uapi/linux/iommu.h >> @@ -142,4 +142,10 @@ struct iommu_cache_invalidate_info { >> __u64 arch_id; >> __u64 addr; >> }; >> + >> +struct iommu_guest_msi_binding { >> + __u64 iova; >> + __u64 gpa; >> + __u32 granule; > > What's granule? The size? This looks a lot like just a stage 1 > mapping interface, I can't really figure out from the description how > this matches to any specific MSI mapping. Yes that's just a stage 1 binding. The granule is the log2size of the stage1 page. As this is a guest mapping of a virtual doorbell, this is WRITE only. What about something like: /** * 1st level/stage1 binding of a virtual MSI doorbell * * @iova: iova * @gpa: guest physical address of the virtual doorbell * @log2size: log2size of the doorbell (generally a guest page) * * As this is an MSI doorbell, the mapping is write only. */ struct iommu_guest_msi_binding { __u64 iova; __u64 gpa; __u32 log2size; }; Also added: /** * iommu_bind_guest_msi - Passes the stage1 binding of the virtual * doorbell used by the assigned device @dev. * * @domain: iommu domain the stage 1 mapping will be attached to * @dev: assigned device which uses this stage1 mapping * @binding: stage1 MSI binding * * The associated IOVA can be reused by the host to create a nested * stage2 binding mapping onto the physical doorbell used by @dev */ Thanks Eric Zero comments in the code > or headers here about how this is supposed to work. Thanks, > > Alex >