From patchwork Fri May 3 17:15:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andre Przywara X-Patchwork-Id: 10929073 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A818214B6 for ; Fri, 3 May 2019 17:16:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9A9E5285B0 for ; Fri, 3 May 2019 17:16:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8EE05285CB; Fri, 3 May 2019 17:16:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2A97F285B0 for ; Fri, 3 May 2019 17:16:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728798AbfECRP7 (ORCPT ); Fri, 3 May 2019 13:15:59 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:37644 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728786AbfECRP6 (ORCPT ); Fri, 3 May 2019 13:15:58 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2B1DE15A2; Fri, 3 May 2019 10:15:58 -0700 (PDT) Received: from donnerap.arm.com (donnerap.cambridge.arm.com [10.1.197.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 358E63F557; Fri, 3 May 2019 10:15:57 -0700 (PDT) From: Andre Przywara To: Will Deacon Cc: Jean-Philippe Brucker , kvm@vger.kernel.org Subject: [PATCH kvmtool 3/4] vfio: rework vfio_irq_set payload setting Date: Fri, 3 May 2019 18:15:43 +0100 Message-Id: <20190503171544.260901-4-andre.przywara@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190503171544.260901-1-andre.przywara@arm.com> References: <20190503171544.260901-1-andre.przywara@arm.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP struct vfio_irq_set from the kernel headers contains a variable sized array to hold a payload. The vfio_irq_eventfd struct puts the "fd" member right after this, hoping it to automatically fit in the payload slot. But having a variable sized type not at the end of a struct is a GNU C extension, so clang will refuse to compile this. Solve this by somewhat doing the compiler's job and place the payload manually at the end of the structure. Signed-off-by: Andre Przywara Reviewed-by: Jean-Philippe Brucker --- vfio/pci.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/vfio/pci.c b/vfio/pci.c index a4086326..76e24c15 100644 --- a/vfio/pci.c +++ b/vfio/pci.c @@ -9,11 +9,16 @@ #include /* Wrapper around UAPI vfio_irq_set */ -struct vfio_irq_eventfd { +union vfio_irq_eventfd { struct vfio_irq_set irq; - int fd; + u8 buffer[sizeof(struct vfio_irq_set) + sizeof(int)]; }; +static void set_vfio_irq_eventd_payload(union vfio_irq_eventfd *evfd, int fd) +{ + memcpy(&evfd->irq.data, &fd, sizeof(fd)); +} + #define msi_is_enabled(state) ((state) & VFIO_PCI_MSI_STATE_ENABLED) #define msi_is_masked(state) ((state) & VFIO_PCI_MSI_STATE_MASKED) #define msi_is_empty(state) ((state) & VFIO_PCI_MSI_STATE_EMPTY) @@ -38,7 +43,7 @@ static int vfio_pci_enable_msis(struct kvm *kvm, struct vfio_device *vdev, int *eventfds; struct vfio_pci_device *pdev = &vdev->pci; struct vfio_pci_msi_common *msis = msix ? &pdev->msix : &pdev->msi; - struct vfio_irq_eventfd single = { + union vfio_irq_eventfd single = { .irq = { .argsz = sizeof(single), .flags = VFIO_IRQ_SET_DATA_EVENTFD | @@ -117,7 +122,7 @@ static int vfio_pci_enable_msis(struct kvm *kvm, struct vfio_device *vdev, continue; single.irq.start = i; - single.fd = fd; + set_vfio_irq_eventd_payload(&single, fd); ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &single); if (ret < 0) { @@ -1021,8 +1026,8 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev) { int ret; int trigger_fd, unmask_fd; - struct vfio_irq_eventfd trigger; - struct vfio_irq_eventfd unmask; + union vfio_irq_eventfd trigger; + union vfio_irq_eventfd unmask; struct vfio_pci_device *pdev = &vdev->pci; int gsi = pdev->intx_gsi; @@ -1058,7 +1063,7 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev) .start = 0, .count = 1, }; - trigger.fd = trigger_fd; + set_vfio_irq_eventd_payload(&trigger, trigger_fd); ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger); if (ret < 0) { @@ -1073,7 +1078,7 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev) .start = 0, .count = 1, }; - unmask.fd = unmask_fd; + set_vfio_irq_eventd_payload(&unmask, unmask_fd); ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &unmask); if (ret < 0) {