Re: [PATCH v3] drivers/pci/intel-iommu.c: errors with smaller iommuwidths

[Andrew Morton]

On Mon, 19 Apr 2010 14:44:16 -0700
"Tom Lyon" <pugs@xxxxxxxxx> wrote:

> 
> When using iommu_domain_alloc with the Intel iommu, the domain address width
> is always initialized to 48 bits (agaw 2). __This domain->agaw value is then
> used by pfn_to_dma_pte to (always) build a 4 level page table. __However, not
> all systems support iommu width of 48 or 4 level page tables. __In particular,
> the Core i5-660 and i5-670 support an address width of 36 bits (not 39!), an
> agaw of only 1, and only 3 level page tables.
> 
> This version of the patch simply lops off extra levels of the page tables if
> the agaw value of the iommu is less than what is currently allocated for the
> domain (in intel_iommu_attach_device). If there were already allocated
> addresses above what the new iommu can handle, EFAULT is returned.
> 	Signed-off-by: Tom Lyon <pugs@xxxxxxxxx>

This smells like a 2.6.34 patch.  Do you agree?
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