From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: arm: warning at virt/kvm/arm/vgic.c:1468 Date: Thu, 12 Feb 2015 22:31:01 -0800 Message-ID: <20150213063101.GC47577@lvm> References: <54D714B9.6090106@web.de> <20150213044613.GA47577@lvm> <54DD97E0.4010902@web.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Clx92ZfkiYIKRjnr" Cc: kvm , kvmarm , Marc Zyngier To: Jan Kiszka Return-path: Received: from mail-pa0-f49.google.com ([209.85.220.49]:64292 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751269AbbBMGau (ORCPT ); Fri, 13 Feb 2015 01:30:50 -0500 Received: by mail-pa0-f49.google.com with SMTP id fb1so16795697pad.8 for ; Thu, 12 Feb 2015 22:30:50 -0800 (PST) Content-Disposition: inline In-Reply-To: <54DD97E0.4010902@web.de> Sender: kvm-owner@vger.kernel.org List-ID: --Clx92ZfkiYIKRjnr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 13, 2015 at 07:21:20AM +0100, Jan Kiszka wrote: > Hi Christoffer, >=20 > On 2015-02-13 05:46, Christoffer Dall wrote: > > Hi Jan, > >=20 > > On Sun, Feb 08, 2015 at 08:48:09AM +0100, Jan Kiszka wrote: > >> Hi, > >> > >> after fixing the VM_BUG_ON, my QEMU guest on the Jetson TK1 generally > >> refuses to boot. Once in a while it does, but quickly gets stuck again. > >> In one case I found this in the kernel log (never happened again so > >> far): > >> > >> [ 762.022874] WARNING: CPU: 1 PID: 972 at ../arch/arm/kvm/../../../vi= rt/kvm/arm/vgic.c:1468 kvm_vgic_sync_hwstate+0x314/0x344() > >> [ 762.022884] Modules linked in: > >> [ 762.022902] CPU: 1 PID: 972 Comm: qemu-system-arm Not tainted 3.19.= 0-rc7-00221-gfd7a168-dirty #13 > >> [ 762.022911] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree) > >> [ 762.022937] [] (unwind_backtrace) from [] (show= _stack+0x10/0x14) > >> [ 762.022958] [] (show_stack) from [] (dump_stack= +0x98/0xd8) > >> [ 762.022976] [] (dump_stack) from [] (warn_slowp= ath_common+0x80/0xb0) > >> [ 762.022991] [] (warn_slowpath_common) from [] (= warn_slowpath_null+0x1c/0x24) > >> [ 762.023007] [] (warn_slowpath_null) from [] (kv= m_vgic_sync_hwstate+0x314/0x344) > >> [ 762.023024] [] (kvm_vgic_sync_hwstate) from [] = (kvm_arch_vcpu_ioctl_run+0x210/0x400) > >> [ 762.023041] [] (kvm_arch_vcpu_ioctl_run) from [= ] (kvm_vcpu_ioctl+0x2e4/0x6ec) > >> [ 762.023059] [] (kvm_vcpu_ioctl) from [] (do_vfs= _ioctl+0x40c/0x600) > >> [ 762.023076] [] (do_vfs_ioctl) from [] (SyS_ioct= l+0x34/0x5c) > >> [ 762.023091] [] (SyS_ioctl) from [] (ret_fast_sy= scall+0x0/0x34) > >=20 > > so this means your guest caused a maintenance interrupt and the bit is > > set in the GICH_EISR for the LR in question but the link register state > > is not 0, which is in direct violation of the GIC spec. Hmmmm. > >=20 > > You're not doing any IRQ forwarding stuff or device passthrough here are > > you? >=20 > No, just boring emulation. The command line is >=20 > qemu-system-ar -machine vexpress-a15 -kernel zImage -serial mon:stdio > -append 'console=3DttyAMA0 root=3D/dev/mmcblk0 rw' -snapshot -sd > OpenSuse13-1_arm.img -dtb vexpress-v2p-ca15-tc1.dtb -s -enable-kvm >=20 > >=20 > >> > >> > >> BTW, KVM tracing support on ARM seems like it requires some care. E.g.: > >> kvm_exit does not report an exit reason. The in-kernel vgic also seems > >> to lack instrumentation. Unfortunate. Tracing is usually the first stop > >> when KVM is stuck on a guest. > >=20 > > I know, the exit reason is on my todo list, and Alex B is sitting on > > trace patches for the gic. Coming soon to a git repo near your. >=20 > Cool, looking forward. >=20 > Next thing I noticed is that guest debugging via qemu causes troubles in > kvm mode. For some reason, qemu is unable to write soft-breakpoints, > thus not even a single-step works. Also known? >=20 Yes, Alex Bennee is working on this. -Christoffer --Clx92ZfkiYIKRjnr Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJU3ZolAAoJEEtpOizt6ddyuNcH/19NgkBq4S+eCZfacsijI6DX Ur81evQs4tILYQCrUKTU2MZ3O2RrF79ULDxk0vsD9zgqzX9EYs01TbsQfmN+duix rxvlponc+W8lFCvQlE6R6MWkxrqroOX9e2uSfcN9q5ZdwePU49Qk8t5lV2WkN/8w y6Z7hY0oegxVhObAlY3pqV2iejF2+vAkpe88cvgJOqGOCMKyPCGGSJrkjfp9eEMy l+ZQhab8WjjAh5lJOLR/5fk4LjkoYk9wh+ccpFl8Xk4BQP4A0akZGfIux/IVf9yL nOlPtpto4zfsGphTsWLiycV06//CpC6a/BIlH/F6kjJ/2CceThIyfutbIubEFcs= =zbMa -----END PGP SIGNATURE----- --Clx92ZfkiYIKRjnr--