FAILED: patch "[PATCH] KVM: arm64: Eagerly init vgic dist/redist on vgic creation" failed to apply to 6.19-stable tree

PATCH New [email protected] 2 participants 3 messages Mar 16

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Stable branch arm64 KVM arm64

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[email protected]

author maintainer

2026-03-16 15:26 UTC #0 lore raw

The patch below does not apply to the 6.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.19.y
git checkout FETCH_HEAD
git cherry-pick -x ac6769c8f948dff33265c50e524aebf9aa6f1be0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026031607-maimed-erasable-eac8@gregkh' --subject-prefix 'PATCH 6.19.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ac6769c8f948dff33265c50e524aebf9aa6f1be0 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <[email protected]>
Date: Sat, 28 Feb 2026 16:45:59 +0000
Subject: [PATCH] KVM: arm64: Eagerly init vgic dist/redist on vgic creation

If vgic_allocate_private_irqs_locked() fails for any odd reason, we exit kvm_vgic_create() early, leaving dist->rd_regions uninitialised.

kvm_vgic_dist_destroy() then comes along and walks into the weeds trying to free the RDs. Got to love this stuff.

Solve it by moving all the static initialisation early, and make sure that if we fail halfway, we're in a reasonable shape to perform the rest of the teardown. While at it, reset the vgic model on failure, just in case...

Reported-by [email protected]

Tested-by [email protected]

Fixes b3aa9283c0c50 ("KVM: arm64: vgic: Hoist SGI/PPI alloc from vgic_init() to kvm_create_vgic()")

Link https://lore.kernel.org/r/[email protected] open here

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Zyngier <[email protected]>

Cc [email protected]

arch/arm64/kvm/vgic/vgic-init.c +17 ~~-17~~

index 9b3091ad868c..e9b8b5fc480c 100644
@@ -143,23 +143,6 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm->arch.vgic.in_kernel = true;
 	kvm->arch.vgic.vgic_model = type;
 	kvm->arch.vgic.implementation_rev = KVM_VGIC_IMP_REV_LATEST;
-
-	kvm_for_each_vcpu(i, vcpu, kvm) {
-		ret = vgic_allocate_private_irqs_locked(vcpu, type);
-		if (ret)
-			break;
-	}
-
-	if (ret) {
-		kvm_for_each_vcpu(i, vcpu, kvm) {
-			struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
-			kfree(vgic_cpu->private_irqs);
-			vgic_cpu->private_irqs = NULL;
-		}
-
-		goto out_unlock;
-	}
-
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 
 	aa64pfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;

@@ -176,6 +159,23 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, aa64pfr0);
 	kvm_set_vm_id_reg(kvm, SYS_ID_PFR1_EL1, pfr1);
 
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		ret = vgic_allocate_private_irqs_locked(vcpu, type);
+		if (ret)
+			break;
+	}
+
+	if (ret) {
+		kvm_for_each_vcpu(i, vcpu, kvm) {
+			struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+			kfree(vgic_cpu->private_irqs);
+			vgic_cpu->private_irqs = NULL;
+		}
+
+		kvm->arch.vgic.vgic_model = 0;
+		goto out_unlock;
+	}
+
 	if (type == KVM_DEV_TYPE_ARM_VGIC_V3)
 		kvm->arch.vgic.nassgicap = system_supports_direct_sgis();

Sasha Levin

maintainer

2026-03-16 19:36 UTC #1 lore raw

PATCH 1/2 KVM: arm64: gic: Set vgic_model before initing private IRQs

From: Sascha Bischoff <[email protected]>

[ Upstream commit 9435c1e1431003e23aa34ef8e46c30d09c3dbcb5 ]

Different GIC types require the private IRQs to be initialised differently. GICv5 is the culprit as it supports both a different number of private IRQs, and all of these are PPIs (there are no SGIs). Moreover, as GICv5 uses the top bits of the interrupt ID to encode the type, the intid also needs to computed differently.

Up until now, the GIC model has been set after initialising the private IRQs for a VCPU. Move this earlier to ensure that the GIC model is available when configuring the private IRQs. While we're at it, also move the setting of the in_kernel flag and implementation revision to keep them grouped together as before.

Signed-off-by Sascha Bischoff <[email protected]>

Reviewed-by Jonathan Cameron <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Zyngier <[email protected]>

Stable-dep-of: ac6769c8f948 ("KVM: arm64: Eagerly init vgic dist/redist on vgic creation")

Signed-off-by Sasha Levin <[email protected]>

---
 arch/arm64/kvm/vgic/vgic-init.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

arch/arm64/kvm/vgic/vgic-init.c +4 -4

index dc9f9db310264..86c149537493f 100644
@@ -140,6 +140,10 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		goto out_unlock;
 	}
 
+	kvm->arch.vgic.in_kernel = true;
+	kvm->arch.vgic.vgic_model = type;
+	kvm->arch.vgic.implementation_rev = KVM_VGIC_IMP_REV_LATEST;
+
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		ret = vgic_allocate_private_irqs_locked(vcpu, type);
 		if (ret)

@@ -156,10 +160,6 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		goto out_unlock;
 	}
 
-	kvm->arch.vgic.in_kernel = true;
-	kvm->arch.vgic.vgic_model = type;
-	kvm->arch.vgic.implementation_rev = KVM_VGIC_IMP_REV_LATEST;
-
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 
 	aa64pfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;

Signature · 1 line

2.51.0

Sasha Levin

maintainer

2026-03-16 19:36 UTC #2 lore raw

PATCH 2/2 KVM: arm64: Eagerly init vgic dist/redist on vgic creation

From: Marc Zyngier <[email protected]>

[ Upstream commit ac6769c8f948dff33265c50e524aebf9aa6f1be0 ]

If vgic_allocate_private_irqs_locked() fails for any odd reason, we exit kvm_vgic_create() early, leaving dist->rd_regions uninitialised.

kvm_vgic_dist_destroy() then comes along and walks into the weeds trying to free the RDs. Got to love this stuff.

Reported-by [email protected]

Tested-by [email protected]

Fixes b3aa9283c0c50 ("KVM: arm64: vgic: Hoist SGI/PPI alloc from vgic_init() to kvm_create_vgic()")

Link https://lore.kernel.org/r/[email protected] open here

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Marc Zyngier <[email protected]>

Cc [email protected]

Signed-off-by Sasha Levin <[email protected]>

---
 arch/arm64/kvm/vgic/vgic-init.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

arch/arm64/kvm/vgic/vgic-init.c +16 ~~-16~~

index 86c149537493f..6ed01c7faa91d 100644
@@ -143,6 +143,21 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm->arch.vgic.in_kernel = true;
 	kvm->arch.vgic.vgic_model = type;
 	kvm->arch.vgic.implementation_rev = KVM_VGIC_IMP_REV_LATEST;
+	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
+
+	aa64pfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
+	pfr1 = kvm_read_vm_id_reg(kvm, SYS_ID_PFR1_EL1) & ~ID_PFR1_EL1_GIC;
+
+	if (type == KVM_DEV_TYPE_ARM_VGIC_V2) {
+		kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
+	} else {
+		INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
+		aa64pfr0 |= SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, GIC, IMP);
+		pfr1 |= SYS_FIELD_PREP_ENUM(ID_PFR1_EL1, GIC, GICv3);
+	}
+
+	kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, aa64pfr0);
+	kvm_set_vm_id_reg(kvm, SYS_ID_PFR1_EL1, pfr1);
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		ret = vgic_allocate_private_irqs_locked(vcpu, type);

@@ -157,25 +172,10 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 			vgic_cpu->private_irqs = NULL;
 		}
 
+		kvm->arch.vgic.vgic_model = 0;
 		goto out_unlock;
 	}
 
-	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
-
-	aa64pfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
-	pfr1 = kvm_read_vm_id_reg(kvm, SYS_ID_PFR1_EL1) & ~ID_PFR1_EL1_GIC;
-
-	if (type == KVM_DEV_TYPE_ARM_VGIC_V2) {
-		kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
-	} else {
-		INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
-		aa64pfr0 |= SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, GIC, IMP);
-		pfr1 |= SYS_FIELD_PREP_ENUM(ID_PFR1_EL1, GIC, GICv3);
-	}
-
-	kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, aa64pfr0);
-	kvm_set_vm_id_reg(kvm, SYS_ID_PFR1_EL1, pfr1);
-
 	if (type == KVM_DEV_TYPE_ARM_VGIC_V3)
 		kvm->arch.vgic.nassgicap = system_supports_direct_sgis();

Signature · 1 line

2.51.0