On Fri, Jul 23, 2021 at 09:15:43PM +0200, David Hildenbrand wrote:
> On 23.07.21 16:52, Peter Xu wrote:
> > On Tue, Jul 20, 2021 at 03:03:00PM +0200, David Hildenbrand wrote:
> > > @@ -30,11 +30,13 @@ void tpm_ppi_reset(TPMPPI *tpmppi)
> > > guest_phys_blocks_init(&guest_phys_blocks);
> > > guest_phys_blocks_append(&guest_phys_blocks);
> > > QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
> > > + ram_addr_t mr_start = memory_region_get_ram_addr(block->mr);
> > > +
> > > trace_tpm_ppi_memset(block->host_addr,
> > > block->target_end -
> > > block->target_start);
> > > memset(block->host_addr, 0,
> > > block->target_end - block->target_start);
> > > - memory_region_set_dirty(block->mr, 0,
> > > + memory_region_set_dirty(block->mr, block->target_start -
> > > mr_start,
> > > block->target_end -
> > > block->target_start);
> >
> > target_start should falls in gpa range, while mr_start is ram_addr_t. I am
> > not
> > sure whether this is right..
>
> When I wrote that code I was under the impression that
> memory_region_get_ram_addr() would give the GPA where the memory region
> starts, but ... that's not correct as you point out. "offset" confusion :)
>
> >
> > Neither do I know how to get correct mr offset with the existing info we've
> > got
> > from GuestPhysBlock. Maybe we need to teach guest_phys_blocks_region_add()
> > to
> > also record section->offset_within_region?
>
> We might actually want offset_within_address_space + offset_within_region,
> so we can calculate the GPA difference to see where inside the ramblock we
> end up.
I still think offset_within_region is exactly what we want to fill in here, but
you can do a double check.
>
> I'll have a look next week, thanks for noticing!
Sure!
--
Peter Xu
