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Tue, 22 Feb 2022 08:13:29 +0000 (GMT) Received: from [9.171.12.252] (unknown [9.171.12.252]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 22 Feb 2022 08:13:29 +0000 (GMT) Message-ID: <803275d5-58f4-21d9-8020-e56f05737450@de.ibm.com> Date: Tue, 22 Feb 2022 09:13:29 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v3 1/1] KVM: s390: pv: make use of ultravisor AIV support Content-Language: en-US To: Michael Mueller , kvm@vger.kernel.org Cc: cohuck@redhat.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220209152217.1793281-1-mimu@linux.ibm.com> <20220209152217.1793281-2-mimu@linux.ibm.com> From: Christian Borntraeger In-Reply-To: <20220209152217.1793281-2-mimu@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 0NOii0dwTeZo61rlj5DTBu81nmkp1AhT X-Proofpoint-GUID: sf-kCLE0x2hFhhUQl2edQV6PvZBJDZog X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-02-22_02,2022-02-21_02,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 adultscore=0 mlxscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 priorityscore=1501 spamscore=0 suspectscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202220046 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 09.02.22 um 16:22 schrieb Michael Mueller: > This patch enables the ultravisor adapter interruption vitualization > support indicated by UV feature BIT_UV_FEAT_AIV. This allows ISC > interruption injection directly into the GISA IPM for PV kvm guests. > > Hardware that does not support this feature will continue to use the > UV interruption interception method to deliver ISC interruptions to > PV kvm guests. For this purpose, the ECA_AIV bit for all guest cpus > will be cleared and the GISA will be disabled during PV CPU setup. > > In addition a check in __inject_io() has been removed. That reduces the > required instructions for interruption handling for PV and traditional > kvm guests. > > Signed-off-by: Michael Mueller The CI said the following with gisa_disable in the calltrace. Will drop from next for now. LOCKDEP_CIRCULAR (suite: kvm-unit-tests-kvm, case: -) WARNING: possible circular locking dependency detected 5.17.0-20220221.rc5.git1.b8f0356a093a.300.fc35.s390x+debug #1 Not tainted ------------------------------------------------------ qemu-system-s39/161139 is trying to acquire lock: 0000000280dc0b98 (&kvm->lock){+.+.}-{3:3}, at: kvm_s390_set_tod_clock+0x36/0x220 [kvm] but task is already holding lock: 0000000280f4e4b8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x9a/0xa40 [kvm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&vcpu->mutex){+.+.}-{3:3}: __lock_acquire+0x604/0xbd8 lock_acquire.part.0+0xe2/0x250 lock_acquire+0xb0/0x200 __mutex_lock+0x9e/0x8a0 mutex_lock_nested+0x32/0x40 kvm_s390_gisa_disable+0xa4/0x130 [kvm] kvm_s390_handle_pv+0x718/0x778 [kvm] kvm_arch_vm_ioctl+0x4ac/0x5f8 [kvm] kvm_vm_ioctl+0x336/0x530 [kvm] __s390x_sys_ioctl+0xbe/0x100 __do_syscall+0x1da/0x208 system_call+0x82/0xb0 -> #0 (&kvm->lock){+.+.}-{3:3}: check_prev_add+0xe0/0xed8 validate_chain+0x736/0xb20 __lock_acquire+0x604/0xbd8 lock_acquire.part.0+0xe2/0x250 lock_acquire+0xb0/0x200 __mutex_lock+0x9e/0x8a0 mutex_lock_nested+0x32/0x40 kvm_s390_set_tod_clock+0x36/0x220 [kvm] kvm_s390_handle_b2+0x378/0x728 [kvm] kvm_handle_sie_intercept+0x13a/0x448 [kvm] vcpu_post_run+0x28e/0x560 [kvm] __vcpu_run+0x266/0x388 [kvm] kvm_arch_vcpu_ioctl_run+0x10a/0x270 [kvm] kvm_vcpu_ioctl+0x27c/0xa40 [kvm] __s390x_sys_ioctl+0xbe/0x100 __do_syscall+0x1da/0x208 system_call+0x82/0xb0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&vcpu->mutex); lock(&kvm->lock); lock(&vcpu->mutex); lock(&kvm->lock); *** DEADLOCK *** 2 locks held by qemu-system-s39/161139: #0: 0000000280f4e4b8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x9a/0xa40 [kvm] #1: 0000000280dc47c8 (&kvm->srcu){....}-{0:0}, at: __vcpu_run+0x1d4/0x388 [kvm] stack backtrace: CPU: 10 PID: 161139 Comm: qemu-system-s39 Not tainted 5.17.0-20220221.rc5.git1.b8f0356a093a.300.fc35.s390x+debug #1 Hardware name: IBM 8561 T01 701 (LPAR) Call Trace: [<00000001da4e89de>] dump_stack_lvl+0x8e/0xc8 [<00000001d9876c56>] check_noncircular+0x136/0x158 [<00000001d9877c70>] check_prev_add+0xe0/0xed8 [<00000001d987919e>] validate_chain+0x736/0xb20 [<00000001d987b23c>] __lock_acquire+0x604/0xbd8 [<00000001d987c432>] lock_acquire.part.0+0xe2/0x250 [<00000001d987c650>] lock_acquire+0xb0/0x200 [<00000001da4f72ae>] __mutex_lock+0x9e/0x8a0 [<00000001da4f7ae2>] mutex_lock_nested+0x32/0x40 [<000003ff8070cd6e>] kvm_s390_set_tod_clock+0x36/0x220 [kvm] [<000003ff8071dd68>] kvm_s390_handle_b2+0x378/0x728 [kvm] [<000003ff8071146a>] kvm_handle_sie_intercept+0x13a/0x448 [kvm] [<000003ff8070dd46>] vcpu_post_run+0x28e/0x560 [kvm] [<000003ff8070e27e>] __vcpu_run+0x266/0x388 [kvm] [<000003ff8070eba2>] kvm_arch_vcpu_ioctl_run+0x10a/0x270 [kvm] [<000003ff806f4044>] kvm_vcpu_ioctl+0x27c/0xa40 [kvm] [<00000001d9b47ac6>] __s390x_sys_ioctl+0xbe/0x100 [<00000001da4ec152>] __do_syscall+0x1da/0x208 [<00000001da4fec42>] system_call+0x82/0xb0 INFO: lockdep is turned off.