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SubjectRe: [PATCH] iommu/dma: Fix domain init
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On 21/05/2024 5:45 am, Jerry Snitselaar wrote:
> On Mon, May 20, 2024 at 08:14:44PM GMT, Robin Murphy wrote:
>> Despite carefully rewording the kerneldoc to describe the new direct
>> interaction with dma_range_map, it seems I managed to confuse myself in
>> removing the redundant force_aperture check and ended up making the code
>> not do that at all. This led to dma_range_maps inadvertently being able
>> to set iovad->start_pfn = 0, and all the nonsensical chaos which ensues
>> from there. Restore the correct behaviour of constraining base_pfn to
>> the domain aperture regardless of dma_range_map, and not trying to apply
>> dma_range_map constraints to the basic IOVA domain since they will be
>> properly handled with reserved regions later.
>>
>> Reported-by: Jon Hunter <jonathanh@nvidia.com>
>> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>> Fixes: e28a114243d1 ("iommu/dma: Make limit checks self-contained")
>
> I'm seeing this upstream as ad4750b07d34 ("iommu/dma: Make limit checks self-contained") now.

What, you mean when Linus pulls some patches I wrote he *doesn't* also
rebase my local development branch for me? /facepalm

Joerg, please shout if you'd like a resend for that.

>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>> ---
>
> Tested-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

Thanks!
Robin.

>> drivers/iommu/dma-iommu.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 89a53c2f2cf9..1ec89ca75c59 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -685,15 +685,15 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, struct device *dev
>>
>> /* Check the domain allows at least some access to the device... */
>> if (map) {
>> - dma_addr_t base = dma_range_map_min(map);
>> - if (base > domain->geometry.aperture_end ||
>> + if (dma_range_map_min(map) > domain->geometry.aperture_end ||
>> dma_range_map_max(map) < domain->geometry.aperture_start) {
>> pr_warn("specified DMA range outside IOMMU capability\n");
>> return -EFAULT;
>> }
>> - /* ...then finally give it a kicking to make sure it fits */
>> - base_pfn = max(base, domain->geometry.aperture_start) >> order;
>> }
>> + /* ...then finally give it a kicking to make sure it fits */
>> + base_pfn = max_t(unsigned long, base_pfn,
>> + domain->geometry.aperture_start >> order);
>>
>> /* start_pfn is always nonzero for an already-initialised domain */
>> mutex_lock(&cookie->mutex);
>> --
>> 2.39.2.101.g768bb238c484.dirty
>>
>

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