David Woodhouse 310bc39546 KVM: x86/xen: Avoid deadlock by adding kvm->arch.xen.xen_lock leaf node lock ... In commit 14243b3871 ("KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery") the clever version of me left some helpful notes for those who would come after him: /* * For the irqfd workqueue, using the main kvm->lock mutex is * fine since this function is invoked from kvm_set_irq() with * no other lock held, no srcu. In future if it will be called * directly from a vCPU thread (e.g. on hypercall for an IPI) * then it may need to switch to using a leaf-node mutex for * serializing the shared_info mapping. */ mutex_lock(&kvm->lock); In commit 2fd6df2f2b ("KVM: x86/xen: intercept EVTCHNOP_send from guests") the other version of me ran straight past that comment without reading it, and introduced a potential deadlock by taking vcpu->mutex and kvm->lock in the wrong order. Solve this as originally suggested, by adding a leaf-node lock in the Xen state rather than using kvm->lock for it. Fixes: 2fd6df2f2b ("KVM: x86/xen: intercept EVTCHNOP_send from guests") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20230111180651.14394-4-dwmw2@infradead.org> [Rebase, add docs. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2023-01-11 17:45:58 -05:00
..
acrn	docs: acrn: Introduce ACRN	2021-02-09 10:58:18 +01:00
coco	virt: Add TDX guest driver	2022-11-17 11:04:23 -08:00
hyperv	Documentation: hyperv: Add overview of clocks and timers	2022-07-13 14:04:48 -06:00
kvm	KVM: x86/xen: Avoid deadlock by adding kvm->arch.xen.xen_lock leaf node lock	2023-01-11 17:45:58 -05:00
uml	docs: UML: fix typo	2022-06-24 13:18:21 -06:00
guest-halt-polling.rst	docs: virt: guest-halt-polling.txt convert to ReST	2020-02-12 20:10:08 +01:00
index.rst	virt: Add TDX guest driver	2022-11-17 11:04:23 -08:00
ne_overview.rst	nitro_enclaves: Update documentation for Arm64 support	2021-09-14 11:11:20 +02:00
paravirt_ops.rst