[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] PVH and mtrr/PAT.........

>>> On 20.11.13 at 03:11, Mukesh Rathor <mukesh.rathor@xxxxxxxxxx> wrote:
> After rebasing my dom0 on latest, it didn't boot. After debugging
> couple days, it turned out to be :
> +    if ( is_pvh_domain(d) )
> +    {
> +        if ( direct_mmio )
> +            return MTRR_TYPE_UNCACHABLE;
> +        return MTRR_TYPE_WRBACK;
> +    }
> +
> I had in my patches, missing in epte_get_entry_emt() in latest.
> So, since I don't know much about this, is an HVM guest setting MTRR 
> range types? Looking for suggestions on best way to do this for PVH. 

A HVM guest is permitted to write to (virtual) MTRRs, whereas a PV
guest isn't. I'm inclined to prefer PV behavior here to be used for
PVH (since, as explained by Dongxiao, MTRRs don't really matter
for VMX guests anyway, i.e. the setting of (virtual) MTRRs needs to
get translated to EPT memory types anyway, hence a PVH guest
ought to be fine ignoring the MTRRs altogether and handling memory
types exclusively via PAT mechanisms).


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.