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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 2D9B0C433DF for ; Fri, 15 May 2020 10:59:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F103620709 for ; Fri, 15 May 2020 10:59:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SEcUGYtb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726945AbgEOK7g (ORCPT ); Fri, 15 May 2020 06:59:36 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:20193 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726198AbgEOK7f (ORCPT ); Fri, 15 May 2020 06:59:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589540373; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GZGe4aex54z7fpeMiMbDba5RJDjvo5sLYKa4o6ESDlc=; b=SEcUGYtbG2nrAPxnpO5oGVbwOakGS2EOczuc7XPtFpdPNEPdARXuOo2q27dpiu/Z2HzT/d OzJEAvWFUES4eM765a+s4gGO+TXbZ/CtJjVvcGZUz6u2xNhTrshowvbNKJ3KLjUfuSUwhg /Muy1DCCGTihxS8RM4rKpaQ3routVpk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-109-BrA0sVyWOxu-r7zqYtJWYQ-1; Fri, 15 May 2020 06:59:29 -0400 X-MC-Unique: BrA0sVyWOxu-r7zqYtJWYQ-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 03DE08018A5; Fri, 15 May 2020 10:59:27 +0000 (UTC) Received: from gondolin (ovpn-112-229.ams2.redhat.com [10.36.112.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 702551C8; Fri, 15 May 2020 10:59:19 +0000 (UTC) Date: Fri, 15 May 2020 12:59:16 +0200 From: Cornelia Huck To: Kirti Wankhede Cc: , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH Kernel v20 4/8] vfio iommu: Add ioctl definition for dirty pages tracking Message-ID: <20200515125916.78723321.cohuck@redhat.com> In-Reply-To: <1589488667-9683-5-git-send-email-kwankhede@nvidia.com> References: <1589488667-9683-1-git-send-email-kwankhede@nvidia.com> <1589488667-9683-5-git-send-email-kwankhede@nvidia.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, 15 May 2020 02:07:43 +0530 Kirti Wankhede wrote: > IOMMU container maintains a list of all pages pinned by vfio_pin_pages API. > All pages pinned by vendor driver through this API should be considered as > dirty during migration. When container consists of IOMMU capable device and > all pages are pinned and mapped, then all pages are marked dirty. > Added support to start/stop dirtied pages tracking and to get bitmap of all > dirtied pages for requested IO virtual address range. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > include/uapi/linux/vfio.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index ad9bb5af3463..123de3bc2dce 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1033,6 +1033,12 @@ struct vfio_iommu_type1_dma_map { > > #define VFIO_IOMMU_MAP_DMA _IO(VFIO_TYPE, VFIO_BASE + 13) > > +struct vfio_bitmap { > + __u64 pgsize; /* page size for bitmap in bytes */ > + __u64 size; /* in bytes */ > + __u64 __user *data; /* one bit per page */ > +}; > + > /** > * VFIO_IOMMU_UNMAP_DMA - _IOWR(VFIO_TYPE, VFIO_BASE + 14, > * struct vfio_dma_unmap) > @@ -1059,6 +1065,55 @@ struct vfio_iommu_type1_dma_unmap { > #define VFIO_IOMMU_ENABLE _IO(VFIO_TYPE, VFIO_BASE + 15) > #define VFIO_IOMMU_DISABLE _IO(VFIO_TYPE, VFIO_BASE + 16) > > +/** > + * VFIO_IOMMU_DIRTY_PAGES - _IOWR(VFIO_TYPE, VFIO_BASE + 17, > + * struct vfio_iommu_type1_dirty_bitmap) > + * IOCTL is used for dirty pages tracking. > + * Caller should set flag depending on which operation to perform, details as > + * below: > + * > + * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_START set, indicates > + * migration is active and IOMMU module should track pages which are dirtied or > + * potentially dirtied by device. "Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_START instructs the IOMMU driver to track pages that are dirtied or potentially dirtied by the device; designed to be used when a migration is in progress." ? > + * Dirty pages are tracked until tracking is stopped by user application by > + * setting VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP flag. "...by calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP." ? > + * > + * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP set, indicates > + * IOMMU should stop tracking dirtied pages. "Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP instructs the IOMMU driver to stop tracking dirtied pages." ? > + * > + * When IOCTL is called with VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP flag set, > + * IOCTL returns dirty pages bitmap for IOMMU container during migration for > + * given IOVA range. "Calling the IOCTL with VFIO_IOMMU_DIRTY_PAGES_GET_BITMAP returns the dirty pages bitmap for the IOMMU container for a given IOVA range." ? Q: How does this interact with the two other operations? I imagine getting an empty bitmap before _START and a bitmap-in-progress between _START and _STOP. After _STOP, will subsequent calls always give the same bitmap? > User must provide data[] as the structure > + * vfio_iommu_type1_dirty_bitmap_get through which user provides IOVA range and > + * pgsize. "The user must specify the IOVA range and the pgsize through the vfio_iommu_type1_dirty_bitmap_get structure in the data[] portion." ? > This interface supports to get bitmap of smallest supported pgsize > + * only and can be modified in future to get bitmap of specified pgsize. That's a current restriction? How can the user find out whether it has been lifted (or, more generally, find out which pgsize values are supported)? > + * User must allocate memory for bitmap, zero the bitmap memory and set size > + * of allocated memory in bitmap.size field. "The user must provide a zeroed memory area for the bitmap memory and specify its size in bitmap.size." ? > One bit is used to represent one > + * page consecutively starting from iova offset. User should provide page size > + * in bitmap.pgsize field. s/User/The user/ Is that the 'pgsize' the comment above talks about? > Bit set in bitmap indicates page at that offset from > + * iova is dirty. "A bit set in the bitmap indicates that the page at that offset from iova is dirty." ? > Caller must set argsz including size of structure > + * vfio_iommu_type1_dirty_bitmap_get. s/Caller/The caller/ Does argz also include the size of the bitmap? > + * > + * Only one of the flags _START, STOP and _GET may be specified at a time. s/STOP/_STOP/ (just to be consistent) > + * > + */ > +struct vfio_iommu_type1_dirty_bitmap { > + __u32 argsz; > + __u32 flags; > +#define VFIO_IOMMU_DIRTY_PAGES_FLAG_START (1 << 0) > +#define VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP (1 << 1) > +#define VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP (1 << 2) > + __u8 data[]; > +}; > + > +struct vfio_iommu_type1_dirty_bitmap_get { > + __u64 iova; /* IO virtual address */ > + __u64 size; /* Size of iova range */ > + struct vfio_bitmap bitmap; > +}; That's for type1 only, right? > + > +#define VFIO_IOMMU_DIRTY_PAGES _IO(VFIO_TYPE, VFIO_BASE + 17) > + > /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */ > > /*