Re: [PATCH v5 0/2] MTE support for KVM guest

[Richard Henderson]

On 12/9/20 12:39 PM, Catalin Marinas wrote:
>> I would have thought that the best way is to use TCO, so that we don't have 
>> to
>> have dual mappings (and however many MB of extra page tables that might 
>> imply).
> 
> The problem appears when the VMM wants to use MTE itself (e.g. linked
> against an MTE-aware glibc), toggling TCO is no longer generic enough,
> especially when it comes to device emulation.

But we do know exactly when we're manipulating guest memory -- we have special
routines for that.  So the special routines gain a toggle of TCO around the
exact guest memory manipulation, not a blanket disable of MTE across large
swaths of QEMU.


r~