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* Revert "irqbypass: do not start cons/prod when failed connect"Zhu Lingshan2021-05-151-10/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit a979a6aa009f3c99689432e0cdb5402a4463fb88. The reverted commit may cause VM freeze on arm64 with GICv4, where stopping a consumer is implemented by suspending the VM. Should the connect fail, the VM will not be resumed, which is a bit of a problem. It also erroneously calls the producer destructor unconditionally, which is unexpected. Reported-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Suggested-by: Marc Zyngier <maz@kernel.org> Acked-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> [maz: tags and cc-stable, commit message update] Signed-off-by: Marc Zyngier <maz@kernel.org> Fixes: a979a6aa009f ("irqbypass: do not start cons/prod when failed connect") Link: https://lore.kernel.org/r/3a2c66d6-6ca0-8478-d24b-61e8e3241b20@hisilicon.com Link: https://lore.kernel.org/r/20210508071152.722425-1-lingshan.zhu@intel.com Cc: stable@vger.kernel.org
* irqbypass: do not start cons/prod when failed connectZhu Lingshan2020-08-051-6/+10
| | | | | | | | | | If failed to connect, there is no need to start consumer nor producer. Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> Suggested-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20200731065533.4144-7-lingshan.zhu@intel.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* KVM: lib: use jump label to handle resource release in ↵Miaohe Lin2020-01-081-9/+10
| | | | | | | | | | | irq_bypass_register_producer() Use out_err jump label to handle resource release. It's a good practice to release resource in one place and help eliminate some duplicated code. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: lib: use jump label to handle resource release in ↵Miaohe Lin2020-01-081-9/+10
| | | | | | | | | | | irq_bypass_register_consumer() Use out_err jump label to handle resource release. It's a good practice to release resource in one place and help eliminate some duplicated code. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner2019-06-191-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: eventfd: fix NULL deref irqbypass consumerWanpeng Li2017-01-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reported syzkaller: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass] PGD 0 Oops: 0002 [#1] SMP CPU: 1 PID: 125 Comm: kworker/1:1 Not tainted 4.9.0+ #1 Workqueue: kvm-irqfd-cleanup irqfd_shutdown [kvm] task: ffff9bbe0dfbb900 task.stack: ffffb61802014000 RIP: 0010:irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass] Call Trace: irqfd_shutdown+0x66/0xa0 [kvm] process_one_work+0x16b/0x480 worker_thread+0x4b/0x500 kthread+0x101/0x140 ? process_one_work+0x480/0x480 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x25/0x30 RIP: irq_bypass_unregister_consumer+0x9d/0xb70 [irqbypass] RSP: ffffb61802017e20 CR2: 0000000000000008 The syzkaller folks reported a NULL pointer dereference that due to unregister an consumer which fails registration before. The syzkaller creates two VMs w/ an equal eventfd occasionally. So the second VM fails to register an irqbypass consumer. It will make irqfd as inactive and queue an workqueue work to shutdown irqfd and unregister the irqbypass consumer when eventfd is closed. However, the second consumer has been initialized though it fails registration. So the token(same as the first VM's) is taken to unregister the consumer through the workqueue, the consumer of the first VM is found and unregistered, then NULL deref incurred in the path of deleting consumer from the consumers list. This patch fixes it by making irq_bypass_register/unregister_consumer() looks for the consumer entry based on consumer pointer itself instead of token matching. Reported-by: Dmitry Vyukov <dvyukov@google.com> Suggested-by: Alex Williamson <alex.williamson@redhat.com> Cc: stable@vger.kernel.org Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* irqbypass: Disallow NULL tokenAlex Williamson2016-05-111-1/+11
| | | | | | | | | A NULL token is meaningless and can only lead to unintended problems. Error on registration with a NULL token, ignore de-registrations with a NULL token. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* virt: IRQ bypass managerAlex Williamson2015-10-011-0/+257
When a physical I/O device is assigned to a virtual machine through facilities like VFIO and KVM, the interrupt for the device generally bounces through the host system before being injected into the VM. However, hardware technologies exist that often allow the host to be bypassed for some of these scenarios. Intel Posted Interrupts allow the specified physical edge interrupts to be directly injected into a guest when delivered to a physical processor while the vCPU is running. ARM IRQ Forwarding allows forwarded physical interrupts to be directly deactivated by the guest. The IRQ bypass manager here is meant to provide the shim to connect interrupt producers, generally the host physical device driver, with interrupt consumers, generally the hypervisor, in order to configure these bypass mechanism. To do this, we base the connection on a shared, opaque token. For KVM-VFIO this is expected to be an eventfd_ctx since this is the connection we already use to connect an eventfd to an irqfd on the in-kernel path. When a producer and consumer with matching tokens is found, callbacks via both registered participants allow the bypass facilities to be automatically enabled. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Eric Auger <eric.auger@linaro.org> Tested-by: Eric Auger <eric.auger@linaro.org> Tested-by: Feng Wu <feng.wu@intel.com> Signed-off-by: Feng Wu <feng.wu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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