From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8F72C47256 for ; Tue, 5 May 2020 03:52:56 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 88054206CC for ; Tue, 5 May 2020 03:52:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="onY/dlOG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88054206CC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jVod3-0006sC-HX; Tue, 05 May 2020 03:52:21 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jVod2-0006s7-C3 for xen-devel@lists.xenproject.org; Tue, 05 May 2020 03:52:20 +0000 X-Inumbo-ID: d14f1fbc-8e83-11ea-ae69-bc764e2007e4 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id d14f1fbc-8e83-11ea-ae69-bc764e2007e4; Tue, 05 May 2020 03:52:19 +0000 (UTC) Received: from localhost (c-67-164-102-47.hsd1.ca.comcast.net [67.164.102.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 85F56206CC; Tue, 5 May 2020 03:52:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588650738; bh=u8IJ5l9i78MtyuRFThT6LJOAnz40GV8d96t0Ql3bsV4=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=onY/dlOGASbUswlzO5guNeBsRifxRIuagWHthWGEPlMBe8SPnrsvzh1yEq5yA24nY RXeJ7Y4bQupe+YCJhjimX61qTdjOa9P0qD0o9G6XhZJV7cdmANg8Ul5p+/N/fnrhSK BRIJUar5WB4ZCvtz9rCi6vZ1Axe22EMk6V3fkXIk= Date: Mon, 4 May 2020 20:52:17 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-T480s To: Roman Shaposhnik Subject: Re: Troubles running Xen on Raspberry Pi 4 with 5.6.1 DomU In-Reply-To: Message-ID: References: <20200501114201.GE9902@minyard.net> <20200502021647.GG9902@minyard.net> <4f6ef562-e213-8952-66d6-0f083bf8c593@xen.org> <20200502173529.GH9902@minyard.net> <20200504124453.GI9902@minyard.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Julien Grall , minyard@acm.org, jeff.kubascik@dornerworks.com, Julien Grall , xen-devel@lists.xenproject.org, Stefano Stabellini Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On Mon, 4 May 2020, Roman Shaposhnik wrote: > Hi Julien, > > thank for your patch -- just like Corey I tried it out and it seems to > work fine and gets > me further. At this point, I'm pretty sure I'm past initial > bootstrapping issues and into > what can be basically described as Xen DMA issue of some kind (so I'm > pretty sure > I will need Stefano's help to debug this further). I'm attaching > verbose logs, but the > culprit seems to be: > > [ 2.534292] Unable to handle kernel paging request at virtual > address 000000000026c340 > [ 2.542373] Mem abort info: > [ 2.545257] ESR = 0x96000004 > [ 2.548421] EC = 0x25: DABT (current EL), IL = 32 bits > [ 2.553877] SET = 0, FnV = 0 > [ 2.557023] EA = 0, S1PTW = 0 > [ 2.560297] Data abort info: > [ 2.563258] ISV = 0, ISS = 0x00000004 > [ 2.567208] CM = 0, WnR = 0 > [ 2.570294] [000000000026c340] user address but active_mm is swapper > [ 2.576783] Internal error: Oops: 96000004 [#1] SMP > [ 2.581784] Modules linked in: > [ 2.584950] CPU: 3 PID: 135 Comm: kworker/3:1 Not tainted 5.6.1-default #9 > [ 2.591970] Hardware name: Raspberry Pi 4 Model B (DT) > [ 2.597256] Workqueue: events deferred_probe_work_func > [ 2.602509] pstate: 60000005 (nZCv daif -PAN -UAO) > [ 2.607431] pc : xen_swiotlb_free_coherent+0x198/0x1d8 > [ 2.612696] lr : dma_free_attrs+0x98/0xd0 > [ 2.616827] sp : ffff800011db3970 > [ 2.620242] x29: ffff800011db3970 x28: 00000000000f7b00 > [ 2.625695] x27: 0000000000001000 x26: ffff000037b68410 > [ 2.631129] x25: 0000000000000001 x24: 00000000f7b00000 > [ 2.636583] x23: 0000000000000000 x22: 0000000000000000 > [ 2.642017] x21: ffff800011b0d000 x20: ffff80001179b548 > [ 2.647461] x19: ffff000037b68410 x18: 0000000000000010 > [ 2.652905] x17: ffff000035d66a00 x16: 00000000deadbeef > [ 2.658348] x15: ffffffffffffffff x14: ffff80001179b548 > [ 2.663792] x13: ffff800091db37b7 x12: ffff800011db37bf > [ 2.669236] x11: ffff8000117c7000 x10: ffff800011db3740 > [ 2.674680] x9 : 00000000ffffffd0 x8 : ffff80001071e980 > [ 2.680124] x7 : 0000000000000132 x6 : ffff80001197a6ab > [ 2.685568] x5 : 0000000000000000 x4 : 0000000000000000 > [ 2.691012] x3 : 00000000f7b00000 x2 : fffffdffffe00000 > [ 2.696465] x1 : 000000000026c340 x0 : 000002000046c340 > [ 2.701899] Call trace: > [ 2.704452] xen_swiotlb_free_coherent+0x198/0x1d8 > [ 2.709367] dma_free_attrs+0x98/0xd0 > [ 2.713143] rpi_firmware_property_list+0x1e4/0x240 > [ 2.718146] rpi_firmware_property+0x6c/0xb0 > [ 2.722535] rpi_firmware_probe+0xf0/0x1e0 > [ 2.726760] platform_drv_probe+0x50/0xa0 > [ 2.730879] really_probe+0xd8/0x438 > [ 2.734567] driver_probe_device+0xdc/0x130 > [ 2.738870] __device_attach_driver+0x88/0x108 > [ 2.743434] bus_for_each_drv+0x78/0xc8 > [ 2.747386] __device_attach+0xd4/0x158 > [ 2.751337] device_initial_probe+0x10/0x18 > [ 2.755649] bus_probe_device+0x90/0x98 > [ 2.759590] deferred_probe_work_func+0x88/0xd8 > [ 2.764244] process_one_work+0x1f0/0x3c0 > [ 2.768369] worker_thread+0x138/0x570 > [ 2.772234] kthread+0x118/0x120 > [ 2.775571] ret_from_fork+0x10/0x18 > [ 2.779263] Code: d34cfc00 f2dfbfe2 d37ae400 8b020001 (f8626800) > [ 2.785492] ---[ end trace 4c435212e349f45f ]--- > [ 2.793340] usb 1-1: New USB device found, idVendor=2109, > idProduct=3431, bcdDevice= 4.20 > [ 2.801038] usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0 > [ 2.808297] usb 1-1: Product: USB2.0 Hub > [ 2.813710] hub 1-1:1.0: USB hub found > [ 2.817117] hub 1-1:1.0: 4 ports detected > > This is bailing out right here: > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/firmware/raspberrypi.c?h=v5.6.1#n125 > > FYIW (since I modified the source to actually print what was returned > right before it bails) we get: > buf[1] == 0x800000004 > buf[2] == 0x00000001 > > Status 0x800000004 is of course suspicious since it is not even listed here: > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/soc/bcm2835/raspberrypi-firmware.h#n14 > > So it appears that this DMA request path is somehow busted and it > would be really nice to figure out why. You have actually discovered a genuine bug in the recent xen dma rework in Linux. Congrats :-) I am doing some guesswork here, but from what I read in the thread and the information in this email I think this patch might fix the issue. If it doesn't fix the issue please add a few printks in drivers/xen/swiotlb-xen.c:xen_swiotlb_free_coherent and please let me know where exactly it crashes. diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h index b9cc11e887ed..ff4677ed9788 100644 --- a/include/xen/arm/page-coherent.h +++ b/include/xen/arm/page-coherent.h @@ -8,12 +8,17 @@ static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs) { + void *cpu_addr; + if (dma_alloc_from_dev_coherent(hwdev, size, dma_handle, &cpu_addr)) + return cpu_addr; return dma_direct_alloc(hwdev, size, dma_handle, flags, attrs); } static inline void xen_free_coherent_pages(struct device *hwdev, size_t size, void *cpu_addr, dma_addr_t dma_handle, unsigned long attrs) { + if (dma_release_from_dev_coherent(hwdev, get_order(size), cpu_addr)) + return; dma_direct_free(hwdev, size, cpu_addr, dma_handle, attrs); }