On 2015/5/5 17:24, Jan Beulich wrote:
On 05.05.15 at 04:45, <tiejun.c...@intel.com> wrote:
Does this work for everyone?
Please first of all explain why the interfaces in asm/flushtlb.h can't
be used here (at least when flushing entire pages). Because - as
I also don't understand any reason we didn't use this previously on
IOMMU side...
said before - for a complete fix you'd need to deal with the CLFLUSH
use(s) elsewhere in the system too.
Looks we need to do this in xen/arch/x86/flushtlb.c:flush_area_local().
Btw, isn't the !iommus_incoherent check in that function inverted?
I.e. why would we _not_ need to flush caches when IOMMUs
are not coherent (and why would flushing be needed when they're
coherent anyway)?
I guess you're misunderstanding this
if ( !ecap_coherent(iommu->ecap) )
iommus_incoherent = 1;
So here !iommus_incoherent means IOMMU is coherent and then we don't
need to flush cache in this case.
Thanks
Tiejun
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