On Thu, 24 Feb 2022 18:14:35 +0530
Ani Sinha <a...@anisinha.ca> wrote:
> On Thu, Feb 24, 2022 at 2:33 PM Igor Mammedov <imamm...@redhat.com> wrote:
> >
> > On Wed, 23 Feb 2022 17:30:34 +0530
> > Ani Sinha <a...@anisinha.ca> wrote:
> >
> > > On Wed, Feb 23, 2022 at 2:34 PM Igor Mammedov <imamm...@redhat.com>
> > > wrote:
> > > >
> > > > On Thu, 10 Feb 2022 18:58:21 +0530
> > > > Ani Sinha <a...@anisinha.ca> wrote:
> > > >
> > > > > When adding E820_RESERVED entries we also accidentally allocate
> > > > > dynamic
> > > > > entries. This is incorrect. We should simply return early with the
> > > > > count of
> > > > > the number of reserved entries added.
> > > >
> > > > can you expand commit message to explain what's wrong and
> > > > how problem manifests ... etc.
> > >
> > > The issue has been present for the last 8 years without apparent
> > > visible issues. I think the only issue is that the bug allocates more
> > > memory in the firmware than is actually needed.
> >
> > let me repeat: Why do you think it's an issue or why it's wrong
>
> Allocating more memory than what we need unnecessarily bloats up the
> rom. We should not be allocating memory that we do not use.
see how firmware uses "etc/e820" fwcfg file first, to make up
mind on 'need' part.
>
> >
> > >
> > > >
> > > > >
> > > > > fixes: 7d67110f2d9a6("pc: add etc/e820 fw_cfg file")
> > > > > cc: kra...@redhat.com
> > > > > Signed-off-by: Ani Sinha <a...@anisinha.ca>
> > > > > ---
> > > > > hw/i386/e820_memory_layout.c | 2 ++
> > > > > 1 file changed, 2 insertions(+)
> > > > >
> > > > > diff --git a/hw/i386/e820_memory_layout.c
> > > > > b/hw/i386/e820_memory_layout.c
> > > > > index bcf9eaf837..afb08253a4 100644
> > > > > --- a/hw/i386/e820_memory_layout.c
> > > > > +++ b/hw/i386/e820_memory_layout.c
> > > > > @@ -31,6 +31,8 @@ int e820_add_entry(uint64_t address, uint64_t
> > > > > length, uint32_t type)
> > > > > entry->type = cpu_to_le32(type);
> > > > >
> > > > > e820_reserve.count = cpu_to_le32(index);
> > > > > +
> > > > > + return index;
> > > > > }
> > > >
> > > > this changes e820_table size/content, which is added by
> > > > fw_cfg_add_file() to fwcfg,
> > > > as result it breaks ABI in case of migration.
> > >
> > > Ugh. So should we keep the bug? or do we add config setting to handle
> > > the ABI breakage.
> > >
> >
>
