From patchwork Thu Aug 25 09:00:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12954400 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65F6FC28D13 for ; Thu, 25 Aug 2022 09:00:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237865AbiHYJAu (ORCPT ); Thu, 25 Aug 2022 05:00:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237364AbiHYJAq (ORCPT ); Thu, 25 Aug 2022 05:00:46 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56EEB11148 for ; Thu, 25 Aug 2022 02:00:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661418044; 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=BSy60wqsBxYaliBQ0PgXadVZz5n2x2hGyCocnFPbCAQ=; b=S3w/hvrmvvUhO/0qqY/dvKqya2f+K5/2UANh04jKTU2Wv6jcQlROMvz8SetTU6DXxNd+uj J2eIFdUzU6SsrAQXoW1HAv47FET7+H7Uqak6PFyFTlu54JDswBB/nTvOrPdopL/zqqxWLQ m4CYTO8pIrxANG9VJoWs02xFNLFoq+U= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-272-V1JPNOt3OvGVC9gNKB0ShQ-1; Thu, 25 Aug 2022 05:00:36 -0400 X-MC-Unique: V1JPNOt3OvGVC9gNKB0ShQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1595E382F1AF; Thu, 25 Aug 2022 09:00:36 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.40.194.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4927940CF8ED; Thu, 25 Aug 2022 09:00:33 +0000 (UTC) From: Vitaly Kuznetsov To: linux-hyperv@vger.kernel.org Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-pci@vger.kernel.org, Bjorn Helgaas , Wei Liu , Deepak Rawat , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Dexuan Cui , Michael Kelley Subject: [PATCH v2 3/3] Drivers: hv: Never allocate anything besides framebuffer from framebuffer memory region Date: Thu, 25 Aug 2022 11:00:24 +0200 Message-Id: <20220825090024.1007883-4-vkuznets@redhat.com> In-Reply-To: <20220825090024.1007883-1-vkuznets@redhat.com> References: <20220825090024.1007883-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Passed through PCI device sometimes misbehave on Gen1 VMs when Hyper-V DRM driver is also loaded. Looking at IOMEM assignment, we can see e.g. $ cat /proc/iomem ... f8000000-fffbffff : PCI Bus 0000:00 f8000000-fbffffff : 0000:00:08.0 f8000000-f8001fff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe ... fe0000000-fffffffff : PCI Bus 0000:00 fe0000000-fe07fffff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe fe0000000-fe07fffff : 2ba2:00:02.0 fe0000000-fe07fffff : mlx4_core the interesting part is the 'f8000000' region as it is actually the VM's framebuffer: $ lspci -v ... 0000:00:08.0 VGA compatible controller: Microsoft Corporation Hyper-V virtual VGA (prog-if 00 [VGA controller]) Flags: bus master, fast devsel, latency 0, IRQ 11 Memory at f8000000 (32-bit, non-prefetchable) [size=64M] ... hv_vmbus: registering driver hyperv_drm hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Synthvid Version major 3, minor 5 hyperv_drm 0000:00:08.0: vgaarb: deactivate vga console hyperv_drm 0000:00:08.0: BAR 0: can't reserve [mem 0xf8000000-0xfbffffff] hyperv_drm 5620e0c7-8062-4dce-aeb7-520c7ef76171: [drm] Cannot request framebuffer, boot fb still active? Note: "Cannot request framebuffer" is not a fatal error in hyperv_setup_gen1() as the code assumes there's some other framebuffer device there but we actually have some other PCI device (mlx4 in this case) config space there! The problem appears to be that vmbus_allocate_mmio() can allocate from the reserved framebuffer region (fb_overlap_ok), however, if the request to allocate MMIO comes from some other device before framebuffer region is taken, it can happily use framebuffer region for it. Note, Gen2 VMs are usually unaffected by the issue because framebuffer region is already taken by EFI fb (in case kernel supports it) but Gen1 VMs may have this region unclaimed by the time Hyper-V PCI pass-through driver tries allocating MMIO space if Hyper-V DRM/FB drivers load after it. Devices can be brought up in any sequence so let's resolve the issue by always ignoring 'fb_mmio' region for non-FB requests, even if the region is unclaimed. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley --- drivers/hv/vmbus_drv.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 536f68e563c6..3c833ea60db6 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2331,7 +2331,7 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, bool fb_overlap_ok) { struct resource *iter, *shadow; - resource_size_t range_min, range_max, start; + resource_size_t range_min, range_max, start, end; const char *dev_n = dev_name(&device_obj->device); int retval; @@ -2366,6 +2366,14 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, range_max = iter->end; start = (range_min + align - 1) & ~(align - 1); for (; start + size - 1 <= range_max; start += align) { + end = start + size - 1; + + /* Skip the whole fb_mmio region if not fb_overlap_ok */ + if (!fb_overlap_ok && fb_mmio && + (((start >= fb_mmio->start) && (start <= fb_mmio->end)) || + ((end >= fb_mmio->start) && (end <= fb_mmio->end)))) + continue; + shadow = __request_region(iter, start, size, NULL, IORESOURCE_BUSY); if (!shadow)