2020-12-13 16:38:08

by Eric Auger

[permalink] [raw]
Subject: [PATCH 3/9] KVM: arm64: vgic-v3: Fix error handling in vgic_v3_set_redist_base()

vgic_register_all_redist_iodevs may succeed while
vgic_register_all_redist_iodevs fails. For example this can happen
while adding a redistributor region overlapping a dist region. The
failure only is detected on vgic_register_all_redist_iodevs when
vgic_v3_check_base() gets called.

In such a case, remove the newly added redistributor region and free
it.

Signed-off-by: Eric Auger <[email protected]>
---
arch/arm64/kvm/vgic/vgic-mmio-v3.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index 8e8a862def76..581f0f490000 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -866,8 +866,14 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
* afterwards will register the iodevs when needed.
*/
ret = vgic_register_all_redist_iodevs(kvm);
- if (ret)
+ if (ret) {
+ struct vgic_redist_region *rdreg =
+ vgic_v3_rdist_region_from_index(kvm, index);
+
+ list_del(&rdreg->list);
+ kfree(rdreg);
return ret;
+ }

return 0;
}
--
2.21.3


2020-12-28 15:39:33

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH 3/9] KVM: arm64: vgic-v3: Fix error handling in vgic_v3_set_redist_base()

Hi Eric,

On Sat, 12 Dec 2020 18:50:04 +0000,
Eric Auger <[email protected]> wrote:
>
> vgic_register_all_redist_iodevs may succeed while
> vgic_register_all_redist_iodevs fails. For example this can happen

The same function cannot both fail and succeed ;-) Can you shed some
light on what you had in mind?

> while adding a redistributor region overlapping a dist region. The
> failure only is detected on vgic_register_all_redist_iodevs when
> vgic_v3_check_base() gets called.
>
> In such a case, remove the newly added redistributor region and free
> it.
>
> Signed-off-by: Eric Auger <[email protected]>
> ---
> arch/arm64/kvm/vgic/vgic-mmio-v3.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> index 8e8a862def76..581f0f490000 100644
> --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
> @@ -866,8 +866,14 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
> * afterwards will register the iodevs when needed.
> */
> ret = vgic_register_all_redist_iodevs(kvm);
> - if (ret)
> + if (ret) {
> + struct vgic_redist_region *rdreg =
> + vgic_v3_rdist_region_from_index(kvm, index);
> +

nit: consider splitting declaration and assignment so that we avoid
the line split if you insist on the 80 character limit.

> + list_del(&rdreg->list);
> + kfree(rdreg);
> return ret;
> + }
>
> return 0;
> }
> --
> 2.21.3
>
>

Thanks,

M.

--
Without deviation from the norm, progress is not possible.

2021-01-13 17:22:00

by Eric Auger

[permalink] [raw]
Subject: Re: [PATCH 3/9] KVM: arm64: vgic-v3: Fix error handling in vgic_v3_set_redist_base()

Hi Marc,

On 12/28/20 4:35 PM, Marc Zyngier wrote:
> Hi Eric,
>
> On Sat, 12 Dec 2020 18:50:04 +0000,
> Eric Auger <[email protected]> wrote:
>>
>> vgic_register_all_redist_iodevs may succeed while
>> vgic_register_all_redist_iodevs fails. For example this can happen
>
> The same function cannot both fail and succeed ;-) Can you shed some
> light on what you had in mind?

Damn, I meant vgic_v3_insert_redist_region() can be successful and then
vgic_register_all_redist_iodevs() fails due to detection of overlap.
>
>> while adding a redistributor region overlapping a dist region. The
>> failure only is detected on vgic_register_all_redist_iodevs when
>> vgic_v3_check_base() gets called.
>>
>> In such a case, remove the newly added redistributor region and free
>> it.
>>
>> Signed-off-by: Eric Auger <[email protected]>
>> ---
>> arch/arm64/kvm/vgic/vgic-mmio-v3.c | 8 +++++++-
>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> index 8e8a862def76..581f0f490000 100644
>> --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> @@ -866,8 +866,14 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count)
>> * afterwards will register the iodevs when needed.
>> */
>> ret = vgic_register_all_redist_iodevs(kvm);
>> - if (ret)
>> + if (ret) {
>> + struct vgic_redist_region *rdreg =
>> + vgic_v3_rdist_region_from_index(kvm, index);
>> +
>
> nit: consider splitting declaration and assignment so that we avoid
> the line split if you insist on the 80 character limit.
Sure

Thanks

Eric
>
>> + list_del(&rdreg->list);
>> + kfree(rdreg);
>> return ret;
>> + }
>>
>> return 0;
>> }
>> --
>> 2.21.3
>>
>>
>
> Thanks,
>
> M.
>