From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: arm: warning at virt/kvm/arm/vgic.c:1468 Date: Fri, 13 Feb 2015 07:21:20 +0100 Message-ID: <54DD97E0.4010902@web.de> References: <54D714B9.6090106@web.de> <20150213044613.GA47577@lvm> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="x5meIoKVNuKDAqOSMAago4F3XEqBWdTuR" Cc: kvm , kvmarm , Marc Zyngier To: Christoffer Dall Return-path: Received: from mout.web.de ([212.227.17.12]:55236 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751273AbbBMGVb (ORCPT ); Fri, 13 Feb 2015 01:21:31 -0500 In-Reply-To: <20150213044613.GA47577@lvm> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --x5meIoKVNuKDAqOSMAago4F3XEqBWdTuR Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Christoffer, 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= =2E >> 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 ar= e > you? No, just boring emulation. The command line is 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 >> >> >> 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 sto= p >> 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. Cool, looking forward. 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? Jan --x5meIoKVNuKDAqOSMAago4F3XEqBWdTuR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iEYEARECAAYFAlTdl+AACgkQitSsb3rl5xRMSQCfR0qUSV5SeJxNVgmQt+aGQ8CJ 65AAoL3y+W1HeEQU89mnoLxX0VusP0J3 =bxSg -----END PGP SIGNATURE----- --x5meIoKVNuKDAqOSMAago4F3XEqBWdTuR--