From patchwork Wed Feb 19 18:53:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 11392295 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DC4DB159A for ; Wed, 19 Feb 2020 18:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD70A24676 for ; Wed, 19 Feb 2020 18:54:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rg0ZKshp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726856AbgBSSyD (ORCPT ); Wed, 19 Feb 2020 13:54:03 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:28978 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726648AbgBSSyC (ORCPT ); Wed, 19 Feb 2020 13:54:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582138441; 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; bh=ooAVZmPqmpejcE1lho8HJzD9Jr6TIc1QTP2vQodr9hU=; b=Rg0ZKshp8M0pAWk5gZuBEelgHbs2ORrC0rE/Rqtr5/rnNszDExFMOODikKlfYvoRoCnk9D EOZkoXkMU6Ufghls0w8C3+1YkkFpteX5ek0aSwpmZPQIosDuuaboy6j6JgPCcTxyJmKA41 3H6gfoUC7wUDnSDz0CHMvarukTOpyhM= 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-56-JYUDF0GWNu6vXN8CwF6baQ-1; Wed, 19 Feb 2020 13:53:51 -0500 X-MC-Unique: JYUDF0GWNu6vXN8CwF6baQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1F401107ACC5; Wed, 19 Feb 2020 18:53:50 +0000 (UTC) Received: from gimli.home (ovpn-116-28.phx2.redhat.com [10.3.116.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 80B505C1B0; Wed, 19 Feb 2020 18:53:46 +0000 (UTC) Subject: [PATCH v2 0/7] vfio/pci: SR-IOV support From: Alex Williamson To: kvm@vger.kernel.org Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dev@dpdk.org, mtosatti@redhat.com, thomas@monjalon.net, bluca@debian.org, jerinjacobk@gmail.com, bruce.richardson@intel.com, cohuck@redhat.com Date: Wed, 19 Feb 2020 11:53:46 -0700 Message-ID: <158213716959.17090.8399427017403507114.stgit@gimli.home> User-Agent: StGit/0.19-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Changes since v1 are primarily to patch 3/7 where the commit log is rewritten, along with option parsing and failure logging based on upstream discussions. The primary user visible difference is that option parsing is now much more strict. If a vf_token option is provided that cannot be used, we generate an error. As a result of this, opening a PF with a vf_token option will serve as a mechanism of setting the vf_token. This seems like a more user friendly API than the alternative of sometimes requiring the option (VFs in use) and sometimes rejecting it, and upholds our desire that the option is always either used or rejected. This also means that the VFIO_DEVICE_FEATURE ioctl is not the only means of setting the VF token, which might call into question whether we absolutely need this new ioctl. Currently I'm keeping it because I can imagine use cases, for example if a hypervisor were to support SR-IOV, the PF device might be opened without consideration for a VF token and we'd require the hypservisor to close and re-open the PF in order to set a known VF token, which is impractical. Series overview (same as provided with v1): The synopsis of this series is that we have an ongoing desire to drive PCIe SR-IOV PFs from userspace with VFIO. There's an immediate need for this with DPDK drivers and potentially interesting future use cases in virtualization. We've been reluctant to add this support previously due to the dependency and trust relationship between the VF device and PF driver. Minimally the PF driver can induce a denial of service to the VF, but depending on the specific implementation, the PF driver might also be responsible for moving data between VFs or have direct access to the state of the VF, including data or state otherwise private to the VF or VF driver. To help resolve these concerns, we introduce a VF token into the VFIO PCI ABI, which acts as a shared secret key between drivers. The userspace PF driver is required to set the VF token to a known value and userspace VF drivers are required to provide the token to access the VF device. If a PF driver is restarted with VF drivers in use, it must also provide the current token in order to prevent a rogue untrusted PF driver from replacing a known driver. The degree to which this new token is considered secret is left to the userspace drivers, the kernel intentionally provides no means to retrieve the current token. Note that the above token is only required for this new model where both the PF and VF devices are usable through vfio-pci. Existing models of VFIO drivers where the PF is used without SR-IOV enabled or the VF is bound to a userspace driver with an in-kernel, host PF driver are unaffected. The latter configuration above also highlights a new inverted scenario that is now possible, a userspace PF driver with in-kernel VF drivers. I believe this is a scenario that should be allowed, but should not be enabled by default. This series includes code to set a default driver_override for VFs sourced from a vfio-pci user owned PF, such that the VFs are also bound to vfio-pci. This model is compatible with tools like driverctl and allows the system administrator to decide if other bindings should be enabled. The VF token interface above exists only between vfio-pci PF and VF drivers, once a VF is bound to another driver, the administrator has effectively pronounced the device as trusted. The vfio-pci driver will note alternate binding in dmesg for logging and debugging purposes. Please review, comment, and test. The example QEMU implementation provided with the RFC is still current for this version. Thanks, Alex RFC: https://lore.kernel.org/lkml/158085337582.9445.17682266437583505502.stgit@gimli.home/ v1: https://lore.kernel.org/lkml/158145472604.16827.15751375540102298130.stgit@gimli.home/ Tested-by: Vamsi Attunuru --- Alex Williamson (7): vfio: Include optional device match in vfio_device_ops callbacks vfio/pci: Implement match ops vfio/pci: Introduce VF token vfio: Introduce VFIO_DEVICE_FEATURE ioctl and first user vfio/pci: Add sriov_configure support vfio/pci: Remove dev_fmt definition vfio/pci: Cleanup .probe() exit paths drivers/vfio/pci/vfio_pci.c | 383 +++++++++++++++++++++++++++++++++-- drivers/vfio/pci/vfio_pci_private.h | 10 + drivers/vfio/vfio.c | 20 +- include/linux/vfio.h | 4 include/uapi/linux/vfio.h | 37 +++ 5 files changed, 426 insertions(+), 28 deletions(-)