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

[Auger Eric]

Hi Marc,

On 12/28/20 4:35 PM, Marc Zyngier wrote:
> Hi Eric,
> 
> On Sat, 12 Dec 2020 18:50:04 +,
> Eric Auger  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 
>> ---
>>  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..581f0f49 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(>list);
>> +kfree(rdreg);
>>  return ret;
>> +}
>>  
>>  return 0;
>>  }
>> -- 
>> 2.21.3
>>
>>
> 
> Thanks,
> 
>   M.
> 

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

[Marc Zyngier]

Hi Eric,

On Sat, 12 Dec 2020 18:50:04 +,
Eric Auger  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 
> ---
>  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..581f0f49 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(>list);
> + kfree(rdreg);
>   return ret;
> + }
>  
>   return 0;
>  }
> -- 
> 2.21.3
> 
> 

Thanks,

M.

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

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

[Eric Auger]

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 
---
 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..581f0f49 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(>list);
+   kfree(rdreg);
return ret;
+   }
 
return 0;
 }
-- 
2.21.3