2021-06-21 12:20:15

by Eric Auger

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]> # v4.19
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]
---
virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index 6ada2432e37c..71d92096776e 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
@@ -95,8 +95,8 @@ 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);
+ rdreg = list_first_entry_or_null(&vgic->rd_regions,
+ struct vgic_redist_region, list);
if (!rdreg)
addr_ptr = &undef_value;
else
--
2.26.3

2021-06-21 12:22:43

by Eric Auger

Subject: Re: [PATCH] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

Hi,

On 6/21/21 2:18 PM, Eric Auger wrote:
> 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]> # v4.19
> 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]

Maybe I should I prefixed the patch with [stable-4.19]. This is already
on master and in various stable but did not apply on 4.19

Thanks

Eric
> ---
> virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 6ada2432e37c..71d92096776e 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -95,8 +95,8 @@ 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);
> + rdreg = list_first_entry_or_null(&vgic->rd_regions,
> + struct vgic_redist_region, list);
> if (!rdreg)
> addr_ptr = &undef_value;
> else

2021-06-21 12:48:05

by Eric Auger

Subject: Re: [PATCH] KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

Hi,

On 6/21/21 2:18 PM, Eric Auger wrote:
> 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]> # v4.19
> 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]

so I have resent with the [PATCH for-stable-4.19] prefix.
Please ignore that patch and sorry for the mess.

Thanks

Eric
> ---
> virt/kvm/arm/vgic/vgic-kvm-device.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 6ada2432e37c..71d92096776e 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -95,8 +95,8 @@ 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);
> + rdreg = list_first_entry_or_null(&vgic->rd_regions,
> + struct vgic_redist_region, list);
> if (!rdreg)
> addr_ptr = &undef_value;
> else