From patchwork Thu Jan 23 13:47:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 11347915 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 68B6017EF for ; Thu, 23 Jan 2020 13:48:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5053820661 for ; Thu, 23 Jan 2020 13:48:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729017AbgAWNs1 (ORCPT ); Thu, 23 Jan 2020 08:48:27 -0500 Received: from foss.arm.com ([217.140.110.172]:39680 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729028AbgAWNs0 (ORCPT ); Thu, 23 Jan 2020 08:48:26 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AF4501007; Thu, 23 Jan 2020 05:48:25 -0800 (PST) Received: from e123195-lin.cambridge.arm.com (e123195-lin.cambridge.arm.com [10.1.196.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AE9A13F68E; Thu, 23 Jan 2020 05:48:24 -0800 (PST) From: Alexandru Elisei To: kvm@vger.kernel.org Cc: will@kernel.org, julien.thierry.kdev@gmail.com, andre.przywara@arm.com, sami.mujawar@arm.com, lorenzo.pieralisi@arm.com, maz@kernel.org Subject: [PATCH v2 kvmtool 05/30] Check that a PCI device's memory size is power of two Date: Thu, 23 Jan 2020 13:47:40 +0000 Message-Id: <20200123134805.1993-6-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200123134805.1993-1-alexandru.elisei@arm.com> References: <20200123134805.1993-1-alexandru.elisei@arm.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org According to the PCI local bus specification [1], a device's memory size must be a power of two. This is also implicit in the mechanism that a CPU uses to get the memory size requirement for a PCI device. The vesa device requests a memory size that isn't a power of two. According to the same spec [1], a device is allowed to consume more memory than it actually requires. As a result, the amount of memory that the vesa device now reserves has been increased. To prevent slip-ups in the future, a few BUILD_BUG_ON statements were added in places where the memory size is known at compile time. [1] PCI Local Bus Specification Revision 3.0, section 6.2.5.1 Signed-off-by: Alexandru Elisei Reviewed-by: Andre Przywara --- hw/vesa.c | 3 +++ include/kvm/util.h | 2 ++ include/kvm/vesa.h | 6 +++++- virtio/pci.c | 3 +++ 4 files changed, 13 insertions(+), 1 deletion(-) diff --git a/hw/vesa.c b/hw/vesa.c index f3c5114cf4fe..d75b4b316a1e 100644 --- a/hw/vesa.c +++ b/hw/vesa.c @@ -58,6 +58,9 @@ struct framebuffer *vesa__init(struct kvm *kvm) char *mem; int r; + BUILD_BUG_ON(!is_power_of_two(VESA_MEM_SIZE)); + BUILD_BUG_ON(VESA_MEM_SIZE < VESA_BPP/8 * VESA_WIDTH * VESA_HEIGHT); + if (!kvm->cfg.vnc && !kvm->cfg.sdl && !kvm->cfg.gtk) return NULL; diff --git a/include/kvm/util.h b/include/kvm/util.h index 4ca7aa9392b6..199724c4018c 100644 --- a/include/kvm/util.h +++ b/include/kvm/util.h @@ -104,6 +104,8 @@ static inline unsigned long roundup_pow_of_two(unsigned long x) return x ? 1UL << fls_long(x - 1) : 0; } +#define is_power_of_two(x) ((x) > 0 ? ((x) & ((x) - 1)) == 0 : 0) + struct kvm; void *mmap_hugetlbfs(struct kvm *kvm, const char *htlbfs_path, u64 size); void *mmap_anon_or_hugetlbfs(struct kvm *kvm, const char *hugetlbfs_path, u64 size); diff --git a/include/kvm/vesa.h b/include/kvm/vesa.h index 0fac11ab5a9f..e7d971343642 100644 --- a/include/kvm/vesa.h +++ b/include/kvm/vesa.h @@ -5,8 +5,12 @@ #define VESA_HEIGHT 480 #define VESA_MEM_ADDR 0xd0000000 -#define VESA_MEM_SIZE (4*VESA_WIDTH*VESA_HEIGHT) #define VESA_BPP 32 +/* + * We actually only need VESA_BPP/8*VESA_WIDTH*VESA_HEIGHT bytes. But the memory + * size must be a power of 2, so we round up. + */ +#define VESA_MEM_SIZE (1 << 21) struct kvm; struct biosregs; diff --git a/virtio/pci.c b/virtio/pci.c index 99653cad2c0f..04e801827df9 100644 --- a/virtio/pci.c +++ b/virtio/pci.c @@ -435,6 +435,9 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev, vpci->kvm = kvm; vpci->dev = dev; + BUILD_BUG_ON(!is_power_of_two(IOPORT_SIZE)); + BUILD_BUG_ON(!is_power_of_two(PCI_IO_SIZE)); + r = ioport__register(kvm, IOPORT_EMPTY, &virtio_pci__io_ops, IOPORT_SIZE, vdev); if (r < 0) return r;