FAILED: patch "[PATCH] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-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]>.

thanks,

greg k-h

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

From 94ac0835391efc1a30feda6fc908913ec012951e Mon Sep 17 00:00:00 2001
From: Eric Auger <[email protected]>
Date: Mon, 12 Apr 2021 17:00:34 +0200
Subject: [PATCH] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

When reading the base address of the a REDIST region through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the redistributor region list to be populated with a single element.

However list_first_entry() expects the list to be non empty. Instead we should use list_first_entry_or_null which effectively returns NULL if the list is empty.

Fixes dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list")

Cc <[email protected]> # v4.18+

Signed-off-by Eric Auger <[email protected]>

Reported-by Gavin Shan <[email protected]>

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

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

arch/arm64/kvm/vgic/vgic-kvm-device.c +0 -0

index 2f66cf247282..7740995de982 100644

Quoted 44 lines · On Wed, 12 May 2021 11:46:23 +0100, <[email protected]> wrote:

The patch below does not apply to the 4.19-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]>.

thanks,

greg k-h

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

From 94ac0835391efc1a30feda6fc908913ec012951e Mon Sep 17 00:00:00 2001
From: Eric Auger <[email protected]>
Date: Mon, 12 Apr 2021 17:00:34 +0200
Subject: [PATCH] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

When reading the base address of the a REDIST region through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the redistributor region list to be populated with a single element.

However list_first_entry() expects the list to be non empty. Instead we should use list_first_entry_or_null which effectively returns NULL if the list is empty.

Fixes dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list")

Cc <[email protected]> # v4.18+

Signed-off-by Eric Auger <[email protected]>

Reported-by Gavin Shan <[email protected]>

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

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

arch/arm64/kvm/vgic/vgic-kvm-device.c +0 -2

index 2f66cf247282..7740995de982 100644
@@ -87,8 +87,8 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 			r = vgic_v3_set_redist_base(kvm, 0, *addr, 0);
 			goto out;
 		}
-		rdreg = list_first_entry(&vgic->rd_regions,
-					 struct vgic_redist_region, list);

arch/arm64/kvm/vgic/vgic-kvm-device.c int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write) · line 94

Quoted 5 lines

arch/arm64/kvm/vgic/vgic-kvm-device.c +2 -0

+		rdreg = list_first_entry_or_null(&vgic->rd_regions,
+						 struct vgic_redist_region, list);
 		if (!rdreg)
 			addr_ptr = &undef_value;
 		else

Eric, any chance you could look at a potential backport of this patch to both 4.19 and 5.4?

Thanks a lot,

	M.