Marcelo Tosatti a2486020a8 KVM: VMX: update vcpu posted-interrupt descriptor when assigning device ... For VMX, when a vcpu enters HLT emulation, pi_post_block will: 1) Add vcpu to per-cpu list of blocked vcpus. 2) Program the posted-interrupt descriptor "notification vector" to POSTED_INTR_WAKEUP_VECTOR With interrupt remapping, an interrupt will set the PIR bit for the vector programmed for the device on the CPU, test-and-set the ON bit on the posted interrupt descriptor, and if the ON bit is clear generate an interrupt for the notification vector. This way, the target CPU wakes upon a device interrupt and wakes up the target vcpu. Problem is that pi_post_block only programs the notification vector if kvm_arch_has_assigned_device() is true. Its possible for the following to happen: 1) vcpu V HLTs on pcpu P, kvm_arch_has_assigned_device is false, notification vector is not programmed 2) device is assigned to VM 3) device interrupts vcpu V, sets ON bit (notification vector not programmed, so pcpu P remains in idle) 4) vcpu 0 IPIs vcpu V (in guest), but since pi descriptor ON bit is set, kvm_vcpu_kick is skipped 5) vcpu 0 busy spins on vcpu V's response for several seconds, until RCU watchdog NMIs all vCPUs. To fix this, use the start_assignment kvm_x86_ops callback to kick vcpus out of the halt loop, so the notification vector is properly reprogrammed to the wakeup vector. Reported-by: Pei Zhang <pezhang@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Message-Id: <20210526172014.GA29007@fuller.cnet> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2021-05-27 07:58:23 -04:00
..
async_pf.c	mm/gup: remove task_struct pointer for all gup code	2020-08-12 10:58:04 -07:00
async_pf.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504	2019-06-19 17:09:56 +02:00
coalesced_mmio.c	KVM: Stop looking for coalesced MMIO zones if the bus is destroyed	2021-04-20 04:18:51 -04:00
coalesced_mmio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
dirty_ring.c	KVM: x86/mmu: Use an rwlock for the x86 MMU	2021-02-04 05:27:43 -05:00
eventfd.c	kvm/eventfd: Drain events from eventfd in irqfd_wakeup()	2020-11-15 09:49:11 -05:00
irqchip.c	KVM/arm updates for 5.3	2019-07-11 15:14:16 +02:00
Kconfig	entry: Provide infrastructure for work before transitioning to guest mode	2020-07-24 15:03:42 +02:00
kvm_main.c	KVM: VMX: update vcpu posted-interrupt descriptor when assigning device	2021-05-27 07:58:23 -04:00
mmu_lock.h	KVM: x86/mmu: Use an rwlock for the x86 MMU	2021-02-04 05:27:43 -05:00
vfio.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
vfio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00