Marc Zyngier 468ef1530f KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption ... commit b321c31c9b upstream. Xiang reports that VMs occasionally fail to boot on GICv4.1 systems when running a preemptible kernel, as it is possible that a vCPU is blocked without requesting a doorbell interrupt. The issue is that any preemption that occurs between vgic_v4_put() and schedule() on the block path will mark the vPE as nonresident and *not* request a doorbell irq. This occurs because when the vcpu thread is resumed on its way to block, vcpu_load() will make the vPE resident again. Once the vcpu actually blocks, we don't request a doorbell anymore, and the vcpu won't be woken up on interrupt delivery. Fix it by tracking that we're entering WFI, and key the doorbell request on that flag. This allows us not to make the vPE resident when going through a preempt/schedule cycle, meaning we don't lose any state. Cc: stable@vger.kernel.org Fixes: 8e01d9a396 ("KVM: arm64: vgic-v4: Move the GICv4 residency flow to be driven by vcpu_load/put") Reported-by: Xiang Chen <chenxiang66@hisilicon.com> Suggested-by: Zenghui Yu <yuzenghui@huawei.com> Tested-by: Xiang Chen <chenxiang66@hisilicon.com> Co-developed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Zenghui Yu <yuzenghui@huawei.com> Link: https://lore.kernel.org/r/20230713070657.3873244-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> [ modified to wrangle the vCPU flags directly instead of going through the flag helper macros as they have not yet been introduced. Also doing the flag wranging in the kvm_arch_vcpu_{un}blocking() hooks as the introduction of kvm_vcpu_wfi has not yet happened. See: 6109c5a6ab ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook") ] Signed-off-by: James Gowans <jgowans@amazon.com> Acked-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-07-05 09:14:51 +02:00
..
arm_arch_timer.h	KVM: arm64: timers: Move timer registers to the sys_regs file	2020-07-07 09:28:38 +01:00
arm_hypercalls.h	KVM: arm/arm64: Factor out hypercall handling from PSCI code	2019-10-21 19:20:26 +01:00
arm_pmu.h	KVM: arm64: Fix PMU probe ordering	2021-09-20 12:43:34 +01:00
arm_psci.h	KVM: arm/arm64: Factor out hypercall handling from PSCI code	2019-10-21 19:20:26 +01:00
arm_vgic.h	KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption	2024-07-05 09:14:51 +02:00
iodev.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 342	2019-06-05 17:37:07 +02:00