Re: [Qemu-devel] [PATCH] vfio: Align iova also to IOMMU page size

[Pavel Fedin]

 Hello!

> TAGET_PAGE_ALIGN tells us that it *could* be a valid DMA target though.
> The VM model is capable of using that as a page size, which means we
> assume it is and want to generate a fault.

 We seem to have looped back. So...
 It is possible to fix this according to this assumption. In this case we would 
need to make TARGET_PAGE_BITS a variable. If we are emulating ancient armv5te, 
it will be set to 10. For modern targets, ARMv6 and newer, it will be 12.
 Peter, would you ACK this approach? BTW, we even have a kind of hack in 
target-arm/cpu.h:
--- cut ---
#if defined(CONFIG_USER_ONLY)
#define TARGET_PAGE_BITS 12
#else
/* The ARM MMU allows 1k pages.  */
/* ??? Linux doesn't actually use these, and they're deprecated in recent
   architecture revisions.  Maybe a configure option to disable them.  */
#define TARGET_PAGE_BITS 10
#endif
--- cut ---

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia