Re: [PATCH] iommu/amd: page-specific invalidations for more than one page

[Joerg Roedel <joro@8bytes.org>]

On Thu, Apr 08, 2021 at 10:29:25AM +0000, Nadav Amit wrote:
> In the version that you referred me to, iommu_update_domain_tlb() only
> regards the size of the region to be flushed and disregards the
> alignment:
> 
> +	order   = get_order(domain->flush.end - domain->flush.start);
> +	mask    = (0x1000ULL << order) - 1;
> +	address = ((domain->flush.start & ~mask) | (mask >> 1)) & ~0xfffULL;
> 
> 
> If you need to flush for instance the region between 0x1000-0x5000, this
> version would use the address|mask of 0x1000 (16KB page). The version I
> sent regards the alignment, and since the range is not aligned would use
> address|mask of 0x3000 (32KB page).
> 
> IIUC, IOVA allocations today are aligned in such way, but at least in
> the past (looking on 3.19 for the matter), it was not like always like
> that, which can explain the problems.

Yeah, that make sense and explains the data corruption problems. I will
give your patch a try on one of my test machines and consider it for
v5.13 if all goes well.

Thanks,

	Joerg