Hi Alexandru,
On 1/6/21 5:32 PM, Alexandru Elisei wrote:
> Hi Eric,
>
> On 12/12/20 6:50 PM, Eric Auger wrote:
>> KVM_DEV_ARM_VGIC_GRP_ADDR group doc says we should return
>> -EEXIST in case the base address of the redist is already set.
>> We currently return -EINVAL.
>>
>> However we need to return -EINVAL in case a legacy REDIST address
>> is attempted to be set while REDIST_REGIONS were set. This case
>> is discriminated by looking at the count field.
>>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>> ---
>> arch/arm64/kvm/vgic/vgic-mmio-v3.c | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> index 15a6c98ee92f..8e8a862def76 100644
>> --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
>> @@ -792,8 +792,13 @@ static int vgic_v3_insert_redist_region(struct kvm *kvm, uint32_t index,
>> int ret;
>>
>> /* single rdist region already set ?*/
>> - if (!count && !list_empty(rd_regions))
>> - return -EINVAL;
>> + if (!count && !list_empty(rd_regions)) {
>> + rdreg = list_last_entry(rd_regions,
>> + struct vgic_redist_region, list);
>> + if (rdreg->count)
>> + return -EINVAL; /* Mixing REDIST and REDIST_REGION API */
>> + return -EEXIST;
>> + }
>
> A few instructions below:
>
> if (list_empty(rd_regions)) {
> [..]
> } else {
> rdreg = list_last_entry(rd_regions,
> struct vgic_redist_region, list);
> [..]
>
> /* Cannot add an explicitly sized regions after legacy region */
> if (!rdreg->count)
> return -EINVAL;
> }
>
> Isn't this testing for the same thing, but using the opposite condition? Or am I
> misunderstanding the code (quite likely)?
the 1st test sequence handles the case where the legacy
KVM_VGIC_V3_ADDR_TYPE_REDIST is used (!count) while the second handles
the case where the REDIST_REGION is used. Nevertheless I think this can
be simplified into:
if (list_empty(rd_regions)) {
if (index != 0)
return -EINVAL;
} else {
rdreg = list_last_entry(rd_regions,
struct vgic_redist_region, list);
if ((!count) != (!rdreg->count))
return -EINVAL; /* Mix REDIST and REDIST_REGION */
if (!count)
return -EEXIST;
if (index != rdreg->index + 1)
return -EINVAL;
}
>
> Looks to me like KVM_DEV_ARM_VGIC_GRP_ADDR(KVM_VGIC_V3_ADDR_TYPE_REDIST{,_REGION})
> used to return -EEXIST (from vgic_check_ioaddr()) before commit ccc27bf5be7b7
> ("KVM: arm/arm64: Helper to register a new redistributor region") which added the
> vgic_v3_insert_redist_region() function, so bringing back the -EEXIST return code
> looks the right thing to me.
OK thank you for the detailed study.
Eric
>
> Thanks,
> Alex
>>
>> /* cross the end of memory ? */
>> if (base + size < base)
>
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