Re: [Xen-ia64-devel] PV-on-HVM driver for IPF

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Vendredi 25 Août 2006 01:47, Doi.Tsunehisa@xxxxxxxxxxxxxx a écrit :
> Hi Tristan,
>
>   Thank you for your comment.
>
> You (Tristan.Gingold) said:
> >>   I will post patches of PV-on-HVM for IPF.
> >>
> >>   We wrote the patch under this consideration:
> >>
> >>    * Expand hvm_op hypercall
> >>      + Introduce HVMOP_setup_shared_info_page
> >>        - A page allocated on HVM-guest OS is swapped original
> >> shared_info page with this hypercall.
> >>        - In x86 code, original shared_info page is used after pv-on-hvm
> >>          setup with remapping feature in arch depend
> >> HYPERVISOR_memory_op. But, we can't implement same feature for IPF, thus
> >> we select to implement with this method.
> >
> > Can you explain why you can't reuse the HYPERVISOR_memory_op hcall ?
> > It isn't clear for me.
>
>   In x86 code (xen/arch/x86/mm.c), it uses only virtual space of page frame
> allocated by GuestOS, and remaps the vitual space to original share_info
> page frame. But, we can't find same method for IPF.
>
>   Can you suggest us about the remapping method ?
I simply wonder why did you create a new hypercall.  You could have reuse the 
same hypercall, using a slighly different semantic.  But it doesn't really 
matter.

[...]
> > +            if (likely(IS_XEN_HEAP_FRAME(virt_to_page(pgaddr)))) {
> > +                free_domheap_page(virt_to_page(pgaddr));
> > +                free_xenheap_page((void *)pgaddr);
> > +            }
> > +            else {
> > +                put_page(virt_to_page(pgaddr));
> > +            }
> > May create a function to be called by gnttab_setup_table and
> > setup_shared_info_page.
>
>   I think that these function are for only VT-i domain, thus I used
> vmx_ prefix. What do you think about it ?
Sorry I was not clear enough.
This block appears in both function.  I'd suggest to create a function to 
avoid duplicating code.

Tristan.

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