linux-kernel - [RFC PATCH 2/2] KVM: arm64: vgic-its: Unmap all vPEs on shutdown

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Message-ID: <20250623132714.965474-2-dwmw2@infradead.org>
Date: Mon, 23 Jun 2025 14:27:14 +0100
From: David Woodhouse <dwmw2@...radead.org>
To: Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Sebastian Ott <sebott@...hat.com>,
	Andre Przywara <andre.przywara@....com>,
	Thorsten Blum <thorsten.blum@...ux.dev>,
	Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>,
	David Woodhouse <dwmw@...zon.co.uk>,
	linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Subject: [RFC PATCH 2/2] KVM: arm64: vgic-its: Unmap all vPEs on shutdown

From: David Woodhouse <dwmw@...zon.co.uk>

We observed systems going dark on kexec, due to corruption of the new
kernel's text (and sometimes the initrd). This was eventually determined
to be caused by the vLPI pending tables used by the GIC in the previous
kernel, which were not being quiesced properly.

Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
---
 arch/arm64/kvm/arm.c          |  5 +++++
 arch/arm64/kvm/vgic/vgic-v3.c | 14 ++++++++++++++
 include/kvm/arm_vgic.h        |  2 ++
 3 files changed, 21 insertions(+)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 38a91bb5d4c7..2b76f506bc2d 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2164,6 +2164,11 @@ void kvm_arch_disable_virtualization_cpu(void)
 		cpu_hyp_uninit(NULL);
 }
 
+void kvm_arch_shutdown(void)
+{
+	kvm_vgic_v3_shutdown();
+}
+
 #ifdef CONFIG_CPU_PM
 static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 				    unsigned long cmd,
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index b9ad7c42c5b0..6591e8d84855 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -382,6 +382,20 @@ static void map_all_vpes(struct kvm *kvm)
 						dist->its_vm.vpes[i]->irq));
 }
 
+void kvm_vgic_v3_shutdown(void)
+{
+	struct kvm *kvm;
+
+	if (!kvm_vgic_global_state.has_gicv4_1)
+		return;
+
+	mutex_lock(&kvm_lock);
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		unmap_all_vpes(kvm);
+	}
+	mutex_unlock(&kvm_lock);
+}
+
 /*
  * vgic_v3_save_pending_tables - Save the pending tables into guest RAM
  * kvm lock and all vcpu lock must be held
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 4a34f7f0a864..e850ee860238 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -442,6 +442,8 @@ int vgic_v4_put(struct kvm_vcpu *vcpu);
 
 bool vgic_state_is_nested(struct kvm_vcpu *vcpu);
 
+void kvm_vgic_v3_shutdown(void);
+
 /* CPU HP callbacks */
 void kvm_vgic_cpu_up(void);
 void kvm_vgic_cpu_down(void);
-- 
2.49.0