From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44325) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1faaUB-0006uc-3s for qemu-devel@nongnu.org; Wed, 04 Jul 2018 01:37:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1faaU8-0007yX-14 for qemu-devel@nongnu.org; Wed, 04 Jul 2018 01:37:51 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:39742 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1faaU7-0007vI-RA for qemu-devel@nongnu.org; Wed, 04 Jul 2018 01:37:47 -0400 Date: Wed, 4 Jul 2018 08:37:42 +0300 From: "Michael S. Tsirkin" Message-ID: <20180704083618-mutt-send-email-mst@kernel.org> References: <1530270944-11351-1-git-send-email-suzuki.poulose@arm.com> <1530270944-11351-2-git-send-email-suzuki.poulose@arm.com> <20180629200816-mutt-send-email-mst@kernel.org> <5124334c-b3c8-4c59-b652-d26ea1101807@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5124334c-b3c8-4c59-b652-d26ea1101807@arm.com> Subject: Re: [Qemu-devel] [PATCH v3 01/20] virtio: mmio-v1: Validate queue PFN List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Suzuki K Poulose Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, marc.zyngier@arm.com, cdall@kernel.org, eric.auger@redhat.com, julien.grall@arm.com, will.deacon@arm.com, catalin.marinas@arm.com, punit.agrawal@arm.com, qemu-devel@nongnu.org, Jason Wang , Peter Maydel , Jean-Philippe Brucker On Tue, Jul 03, 2018 at 09:04:01AM +0100, Suzuki K Poulose wrote: > Hi Michael, > > On 06/29/2018 06:42 PM, Michael S. Tsirkin wrote: > > On Fri, Jun 29, 2018 at 12:15:21PM +0100, Suzuki K Poulose wrote: > > > virtio-mmio with virtio-v1 uses a 32bit PFN for the queue. > > > If the queue pfn is too large to fit in 32bits, which > > > we could hit on arm64 systems with 52bit physical addresses > > > (even with 64K page size), we simply miss out a proper link > > > to the other side of the queue. > > > > > > Add a check to validate the PFN, rather than silently breaking > > > the devices. > > > > > > Cc: "Michael S. Tsirkin" > > > Cc: Jason Wang > > > Cc: Marc Zyngier > > > Cc: Christoffer Dall > > > Cc: Peter Maydel > > > Cc: Jean-Philippe Brucker > > > Signed-off-by: Suzuki K Poulose > > > --- > > > Changes since v2: > > > - Change errno to -E2BIG > > > --- > > > drivers/virtio/virtio_mmio.c | 18 ++++++++++++++++-- > > > 1 file changed, 16 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c > > > index 67763d3..82cedc8 100644 > > > --- a/drivers/virtio/virtio_mmio.c > > > +++ b/drivers/virtio/virtio_mmio.c > > > @@ -397,9 +397,21 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, > > > /* Activate the queue */ > > > writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); > > > if (vm_dev->version == 1) { > > > + u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT; > > > + > > > + /* > > > + * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something > > > + * that doesn't fit in 32bit, fail the setup rather than > > > + * pretending to be successful. > > > + */ > > > + if (q_pfn >> 32) { > > > + dev_err(&vdev->dev, "virtio-mmio: queue address too large\n"); > > > > How about: > > "hypervisor bug: legacy virtio-mmio must not be used with more than 0x%llx Gigabytes of memory", > > 0x1ULL << (32 - 30) << PAGE_SHIFT > > nit : Do we need change "hypervisor" => "platform" ? Virtio is used by other > tools (e.g, emulators) and not just virtual machines. > > Suzuki OK.