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authorMarc Zyngier <maz@kernel.org>2023-07-13 10:06:57 +0300
committerOliver Upton <oliver.upton@linux.dev>2023-07-14 01:23:34 +0300
commitb321c31c9b7b309dcde5e8854b741c8e6a9a05f0 (patch)
tree1af248412eccb1f5a21edc36725288753f539c09 /include/kvm
parentdcf89d111199562fa5f31a1bb76f17bc4831f6da (diff)
downloadlinux-b321c31c9b7b309dcde5e8854b741c8e6a9a05f0.tar.xz
KVM: arm64: vgic-v4: Make the doorbell request robust w.r.t preemption
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: 8e01d9a396e6 ("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>
Diffstat (limited to 'include/kvm')
-rw-r--r--include/kvm/arm_vgic.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 402b545959af..5b27f94d4fad 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -431,7 +431,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
int vgic_v4_load(struct kvm_vcpu *vcpu);
void vgic_v4_commit(struct kvm_vcpu *vcpu);
-int vgic_v4_put(struct kvm_vcpu *vcpu, bool need_db);
+int vgic_v4_put(struct kvm_vcpu *vcpu);
/* CPU HP callbacks */
void kvm_vgic_cpu_up(void);