From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZqI4okcqP+ObT0W3qd5vSX03zKVCkNPFoq8L4H7DdbqpuiEAHrUE6+3zN2lVMyG7e0ZVKaH ARC-Seal: i=1; a=rsa-sha256; t=1525409016; cv=none; d=google.com; s=arc-20160816; b=EoTuEgVXg1vet6X1Sj2DbuRfNyBJq/m6jpt/DhIGq+AUwPu667e6PUilVBbeTlNcNL ld70p//kEUrq0ONBf3eO9e3RuosliSKE4tjl63/I2xN5XXlGzmVYRE69xoStQwsIMLI6 bv1pJ7gIbhnb3zrZg9F67fpgaiHIfLw6+eWXHOZu7EeCT9PBg9jd+0/vHPPWjMmuDHHH csboqVPznl6e+KNqN5Icf4MLK2sy93lY84ByGas8Benp7gPmDEs4PaTbWmOkOg33oEJu GkBCX0lnx9hSmFRuTWgi+vHDJxWCAkA54GX4Q2qNb2pMY7mPuzoL8RKqLplxPdffNL5Y FGgA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:date :arc-authentication-results; bh=jDxow1AR4SrfaBxdTg1QxNahvHHP5zbWhXh7/Ry3yrk=; b=mmyjuOLoIgQy7jb8+Y675BdatbgXCOzDXkz0N3RPW+080aqQdT3rHvyD0RtPCMwbKv TPMNPPfnuGumdvicSHpzZxNff7r6ZHPyqIn+bXeAmiX9sqpHNVCjm0c8Kj3BA4DU6GDO RTEp23FrURd6BRqvkDSs5beI6cgk+zJ1Sk+E63K6SQmmOxLfW6iDk+51NpzzZkjeXzWJ y4Ib+GDOhbRyj8EuiJJp1CeRnyOdUyOxXS2lHkmwbl+6PCZ+bW5YRC5HmLxNL3kivaUf Wn+XwBC/rKH7Sg50yKasN6JxFVdgOQr+xNyBaVuMuFpEfTlfPXb9Q9I7nffWWZaycwDz apzw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of jacob.jun.pan@linux.intel.com designates 192.55.52.115 as permitted sender) smtp.mailfrom=jacob.jun.pan@linux.intel.com Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of jacob.jun.pan@linux.intel.com designates 192.55.52.115 as permitted sender) smtp.mailfrom=jacob.jun.pan@linux.intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,361,1520924400"; d="scan'208";a="53085446" Date: Thu, 3 May 2018 21:46:16 -0700 From: Jacob Pan To: Jean-Philippe Brucker Cc: "iommu@lists.linux-foundation.org" , LKML , Joerg Roedel , David Woodhouse , Greg Kroah-Hartman , Alex Williamson , Rafael Wysocki , "Liu, Yi L" , "Tian, Kevin" , Raj Ashok , Jean Delvare , Christoph Hellwig , Lu Baolu , "Liu, Yi L" , "Liu@ostrya.localdomain" , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v4 05/22] iommu: introduce iommu invalidate API function Message-ID: <20180503214616.51553247@jacob-builder> In-Reply-To: References: <1523915351-54415-1-git-send-email-jacob.jun.pan@linux.intel.com> <1523915351-54415-6-git-send-email-jacob.jun.pan@linux.intel.com> <20180420181951.GA50099@ostrya.localdomain> <20180423134325.6780f6ac@jacob-builder> <72ee47c4-55fa-4ff1-d94e-cc26203e3eda@arm.com> <20180501155838.4ec3720c@jacob-builder> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597940909254056563?= X-GMAIL-MSGID: =?utf-8?q?1599507285592477651?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, 2 May 2018 10:31:50 +0100 Jean-Philippe Brucker wrote: > On 01/05/18 23:58, Jacob Pan wrote: > >>>> Maybe this should be called "NG_PAGE_PASID", > >>> Sure. I was thinking page range already implies non-global > >>> pages. > >>>> and "DOMAIN_PAGE" should > >>>> instead be "PAGE_PASID". If I understood their meaning correctly, > >>>> it would be more consistent with the rest. > >>>> > >>> I am trying not to mix granu between request w/ PASID and w/o. > >>> DOMAIN_PAGE meant to be for request w/o PASID. > >> > >> Is the distinction necessary? I understand the IOMMU side might > >> offer many possibilities for invalidation, but the user probably > >> doesn't need all of them. It might be easier to document, upstream > >> and maintain if we only specify what's currently needed by users > >> (what does QEMU VT-d use?) Others can always extend it by > >> increasing the version. > >> > >> Do you think that this invalidation message will be used outside of > >> BIND_PASID_TABLE context? I can't see an other use but who knows. > >> At the moment requests w/o PASID are managed with > >> VFIO_IOMMU_MAP/UNMAP_DMA, which doesn't require invalidation. And > >> in a BIND_PASID_TABLE context, IOMMUs requests w/o PASID are just a > >> special case using PASID 0 (for Arm and AMD) so I suppose they'll > >> use the same invalidation commands as requests w/ PASID. > >> > > My understanding is that for GIOVA use case, VT-d vIOMMU creates > > GIOVA-GPA mapping and the host shadows the 2nd level page tables to > > create GIOVA-HPA mapping. So when assigned device in the guest can > > do both DMA map/unmap and VFIO map/unmap, VFIO unmap is one time > > deal (I guess invalidation can be captured in other code path), but > > guest kernel use of DMA unmap could will trigger invalidation. QEMU > > needs to trap those invalidation and passdown to physical IOMMU. So > > we do need invalidation w/o PASID. > > Hm, isn't this all done by host userspace? Whether guest does DMA > map/unmap or VFIO map/unmap, it creates/removes IOVA-GPA mappings in > the vIOMMU. QEMU captures invalidation requests for these mappings > from the guest, finds GPA-HVA in the shadow map and sends a VFIO > map/unmap request for IOVA-HVA. > Sorry for the delay but you are right, I have also confirmed with Yi that we don't need second level invalidation. I will remove IOTLB invalidation w/o PASID case from the API. Thanks, > Thanks, > Jean > [Jacob Pan]