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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5D22CC46467 for ; Thu, 19 Jan 2023 10:24:13 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pIS2F-0006Yb-J6; Thu, 19 Jan 2023 05:20:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pIS1n-0006MG-GA for qemu-devel@nongnu.org; Thu, 19 Jan 2023 05:20:35 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pIS1g-0007vK-Ix for qemu-devel@nongnu.org; Thu, 19 Jan 2023 05:20:14 -0500 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4NyJWs4q2rz6J9pN; Thu, 19 Jan 2023 18:19:21 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Thu, 19 Jan 2023 10:19:47 +0000 Date: Thu, 19 Jan 2023 10:19:46 +0000 To: Gregory Price CC: Lukas Wunner , , Michael Tsirkin , Ben Widawsky , , , Ira Weiny , Gregory Price Subject: Re: [PATCH 0/8] hw/cxl: CXL emulation cleanups and minor fixes for upstream Message-ID: <20230119101946.000079e5@Huawei.com> In-Reply-To: References: <20230111142440.24771-1-Jonathan.Cameron@huawei.com> <20230112172130.0000391b@Huawei.com> <20230113091213.00002146@Huawei.com> <20230113144026.000001fb@Huawei.com> <20230113144511.00001207@Huawei.com> <20230113151206.GA20583@wunner.de> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, 18 Jan 2023 14:22:08 -0500 Gregory Price wrote: > 1) No stack traces present > 2) Device usage appears to work, but cxl-cli fails to create a region, i > haven't checked why yet (also tried ndctl-75, same results) > 3) There seems to be some other regression with the cxl_pmem_init > routine, because I get a stack trace in this setup regardless of whether > I apply the type-3 device commit. > > > All tests below with the previously posted DOE linux branch. > Base QEMU branch was Jonathan's 2023-1-11 > > > DOE Branch - 2023-1-11 (HEAD) (all commits) > > QEMU Config: > sudo /opt/qemu-cxl/bin/qemu-system-x86_64 \ > -drive file=/var/lib/libvirt/images/cxl.qcow2,format=qcow2,index=0,media=disk,id=hd \ > -m 3G,slots=4,maxmem=8G \ > -smp 4 \ > -machine type=q35,accel=kvm,cxl=on \ > -enable-kvm \ > -nographic \ > -object memory-backend-ram,id=mem0,size=1G,share=on \ > -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \ > -device cxl-rp,id=rp0,bus=cxl.0,chassis=0,slot=0 \ > -device cxl-type3,bus=rp0,volatile-memdev=mem0,id=cxl-mem0 \ > -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G > > Result: This worked, but cxl-cli could not create a region (will look > into this further later). > Even if everything else worked, it will currently fail because of the issue with pass through decoders. (Kernel assumes always pass through for single rp, qemu assumes never pass through - both are valid under spec). Add a second rp for now. I should be able to post some patches to work around that shortly. > > > > When running with a persistent memory configuration, I'm seeing a > kernel stack trace on cxl_pmem_init > > Config: > sudo /opt/qemu-cxl/bin/qemu-system-x86_64 \ > -drive file=/var/lib/libvirt/images/cxl.qcow2,format=qcow2,index=0,media=disk,id=hd \ > -m 3G,slots=4,maxmem=4G \ > -smp 4 \ > -machine type=q35,accel=kvm,cxl=on \ > -enable-kvm \ > -nographic \ > -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \ > -device cxl-rp,port=0,id=rp0,bus=cxl.0,chassis=0,slot=0 \ > -object memory-backend-file,id=cxl-mem0,mem-path=/tmp/mem0,size=1G \ > -object memory-backend-file,id=cxl-lsa0,mem-path=/tmp/lsa0,size=1G \ > -device cxl-type3,bus=rp0,persistent-memdev=cxl-mem0,lsa=cxl-lsa0,id=cxl-pmem0 \ > -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G > > > [ 62.167518] BUG: kernel NULL pointer dereference, address: 00000000000004c0 > [ 62.185069] #PF: supervisor read access in kernel mode > [ 62.198502] #PF: error_code(0x0000) - not-present page > [ 62.211019] PGD 0 P4D 0 > [ 62.220521] Oops: 0000 [#1] PREEMPT SMP PTI > [ 62.233457] CPU: 3 PID: 558 Comm: systemd-udevd Not tainted 6.2.0-rc1+ #1 > [ 62.252886] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014 > [ 62.258432] Adding 2939900k swap on /dev/zram0. Priority:100 extents:1 across:2939900k SSDscFS > [ 62.285513] RIP: 0010:cxl_nvdimm_probe+0x8d/0x130 [cxl_pmem] > [ 62.285529] Code: 85 c0 0f 85 90 00 00 00 f0 80 0c 24 40 f0 80 4c 24 08 10 f0 80 4c 24 08 20 f0 80 4c 24 08 40 49 8d 84 24 b8 04 00 00 4c 89 0 > [ 62.285531] RSP: 0018:ffffacff0141fc38 EFLAGS: 00010202 > [ 62.285534] RAX: ffff97a8a37b84b8 RBX: ffff97a8a37b8000 RCX: 0000000000000000 > [ 62.285536] RDX: 0000000000000001 RSI: ffff97a8a37b8000 RDI: 00000000ffffffff > [ 62.285537] RBP: ffff97a8a37b8000 R08: 0000000000000001 R09: 0000000000000001 > [ 62.285538] R10: 0000000000000001 R11: 0000000000000000 R12: ffff97a8a37b8000 > [ 62.285539] R13: ffff97a982c3dc28 R14: 0000000000000000 R15: 0000000000000000 > [ 62.285541] FS: 00007f2619829580(0000) GS:ffff97a9bca00000(0000) knlGS:0000000000000000 > [ 62.285542] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 62.285544] CR2: 00000000000004c0 CR3: 00000001056a8000 CR4: 00000000000006e0 > [ 62.285653] Call Trace: > [ 62.285656] > [ 62.285660] cxl_bus_probe+0x17/0x50 > [ 62.285691] really_probe+0xde/0x380 > [ 62.285695] ? pm_runtime_barrier+0x50/0x90 > [ 62.285700] __driver_probe_device+0x78/0x170 > [ 62.285846] driver_probe_device+0x1f/0x90 > [ 62.285850] __driver_attach+0xd2/0x1c0 > [ 62.285853] ? __pfx___driver_attach+0x10/0x10 > [ 62.285856] bus_for_each_dev+0x76/0xa0 > [ 62.285860] bus_add_driver+0x1b1/0x200 > [ 62.285863] driver_register+0x89/0xe0 > [ 62.285868] ? __pfx_init_module+0x10/0x10 [cxl_pmem] > [ 62.285874] cxl_pmem_init+0x50/0xff0 [cxl_pmem] > [ 62.285880] do_one_initcall+0x6e/0x330 > [ 62.285888] do_init_module+0x4a/0x200 > [ 62.285892] __do_sys_finit_module+0x93/0xf0 > [ 62.285899] do_syscall_64+0x5b/0x80 > [ 62.285904] ? do_syscall_64+0x67/0x80 > [ 62.285906] ? asm_exc_page_fault+0x22/0x30 > [ 62.285910] ? lockdep_hardirqs_on+0x7d/0x100 > [ 62.285914] entry_SYSCALL_64_after_hwframe+0x72/0xdc > [ 62.285917] RIP: 0033:0x7f2619b0afbd > [ 62.285920] Code: 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 8 > [ 62.285922] RSP: 002b:00007ffcc516bf58 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 > [ 62.285924] RAX: ffffffffffffffda RBX: 00005557c0dcaa60 RCX: 00007f2619b0afbd > [ 62.285925] RDX: 0000000000000000 RSI: 00007f261a18743c RDI: 0000000000000006 > [ 62.285926] RBP: 00007f261a18743c R08: 0000000000000000 R09: 00007f261a17bb52 > [ 62.285927] R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000020000 > [ 62.285928] R13: 00005557c0dbbce0 R14: 0000000000000000 R15: 00005557c0dc18a0 > [ 62.285932] > [ 62.285933] Modules linked in: cxl_pmem(+) snd_pcm libnvdimm snd_timer snd joydev bochs cxl_mem drm_vram_helper parport_pc soundcore drm_ttm_g > [ 62.285954] CR2: 00000000000004c0 > [ 62.288385] ---[ end trace 0000000000000000 ]--- > [ 63.203514] RIP: 0010:cxl_nvdimm_probe+0x8d/0x130 [cxl_pmem] > [ 63.203562] Code: 85 c0 0f 85 90 00 00 00 f0 80 0c 24 40 f0 80 4c 24 08 10 f0 80 4c 24 08 20 f0 80 4c 24 08 40 49 8d 84 24 b8 04 00 00 4c 89 0 > [ 63.203565] RSP: 0018:ffffacff0141fc38 EFLAGS: 00010202 > [ 63.203570] RAX: ffff97a8a37b84b8 RBX: ffff97a8a37b8000 RCX: 0000000000000000 > [ 63.203572] RDX: 0000000000000001 RSI: ffff97a8a37b8000 RDI: 00000000ffffffff > [ 63.203574] RBP: ffff97a8a37b8000 R08: 0000000000000001 R09: 0000000000000001 > [ 63.203576] R10: 0000000000000001 R11: 0000000000000000 R12: ffff97a8a37b8000 > [ 63.203577] R13: ffff97a982c3dc28 R14: 0000000000000000 R15: 0000000000000000 > [ 63.203580] FS: 00007f2619829580(0000) GS:ffff97a9bca00000(0000) knlGS:0000000000000000 > [ 63.203583] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 63.203585] CR2: 00000000000004c0 CR3: 00000001056a8000 CR4: 00000000000006e0 > I clearly need to run some more rests as not seen this issue (and I've had a couple of reports of it now). I guess I never tend to be running a completely clean tree on either side + testing is mostly on arm64 (though I doubt that matters). It's not the pass through decoder issues as that is visible only when bringing up a region. > > > Next i reverted the QEMU branch to the commit just before the type-3 > volatile commit and used the old method of launching with a type-3 pmem > device > > Config: > sudo /opt/qemu-cxl/bin/qemu-system-x86_64 \ > -drive file=/var/lib/libvirt/images/cxl.qcow2,format=qcow2,index=0,media=disk,id=hd \ > -m 2G,slots=4,maxmem=4G \ > -smp 4 \ > -machine type=q35,accel=kvm,cxl=on \ > -enable-kvm \ > -nographic \ > -device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 \ > -device cxl-rp,id=rp0,bus=cxl.0,chassis=0,slot=0 \ > -object memory-backend-file,pmem=true,id=cxl-mem0,mem-path=/tmp/cxl-mem0,size=1G \ > -object memory-backend-file,pmem=true,id=lsa0,mem-path=/tmp/cxl-lsa0,size=1G \ > -device cxl-type3,bus=rp0,memdev=cxl-mem0,lsa=lsa0,id=cxl-pmem0 \ > -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=1G > > > Result: Similar stack trace > [ 29.850023] BUG: kernel NULL pointer dereference, address: 00000000000004c0 > [ 29.882400] RIP: 0010:cxl_nvdimm_probe+0x8d/0x130 [cxl_pmem] > [ 29.957485] Call Trace: > [ 29.959067] > [ 29.962176] cxl_bus_probe+0x17/0x50 > [ 29.964940] really_probe+0xde/0x380 > [ 29.969065] ? pm_runtime_barrier+0x50/0x90 > [ 29.973419] __driver_probe_device+0x78/0x170 > [ 29.977183] driver_probe_device+0x1f/0x90 > [ 29.984212] __driver_attach+0xd2/0x1c0 > [ 29.988463] ? __pfx___driver_attach+0x10/0x10 > [ 29.992379] bus_for_each_dev+0x76/0xa0 > [ 29.997040] bus_add_driver+0x1b1/0x200 > [ 30.000368] driver_register+0x89/0xe0 > [ 30.004579] ? __pfx_init_module+0x10/0x10 [cxl_pmem] > [ 30.012403] cxl_pmem_init+0x50/0xff0 [cxl_pmem] > [ 30.019394] do_one_initcall+0x6e/0x330 > [ 30.024028] do_init_module+0x4a/0x200 > [ 30.029243] __do_sys_finit_module+0x93/0xf0 > [ 30.034943] do_syscall_64+0x5b/0x80 > [ 30.039844] ? do_syscall_64+0x67/0x80 > [ 30.045163] ? do_syscall_64+0x67/0x80 > [ 30.049729] ? lock_release+0x14b/0x440 > [ 30.054055] ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90 > [ 30.061039] ? lock_is_held_type+0xe8/0x140 > [ 30.067625] ? do_syscall_64+0x67/0x80 > [ 30.071909] ? lockdep_hardirqs_on+0x7d/0x100 > [ 30.079037] ? do_syscall_64+0x67/0x80 > [ 30.084537] ? do_syscall_64+0x67/0x80 > [ 30.089091] ? do_syscall_64+0x67/0x80 > [ 30.094174] ? lockdep_hardirqs_on+0x7d/0x100 > [ 30.099224] entry_SYSCALL_64_after_hwframe+0x72/0xdc > [ 30.104446] RIP: 0033:0x7f000550afbd