Re: [RFC 0/2] UEFI-based HTTP Boot

[Michael Chang <mchang@suse.com>]

On Fri, Jan 20, 2017 at 05:50:56PM +0300, Andrei Borzenkov wrote:
> On Fri, Jan 20, 2017 at 4:13 AM, Ken Lin <ken.lin@hpe.com> wrote:
> > This RFC patchset is stacked on the previous HTTP boot patchset:
> > https://lists.gnu.org/archive/html/grub-devel/2016-12/msg00088.html
> > It re-uses some code from it, e.g. the DCHPACK
> > with vendor_class_identifier=HTTPClient.
> >
> > Instead of implementing HTTP and HTTPS boot totally from software,
> > UEFI firmware already defines APIs for HTTP(s).
> > Please check UEFI spec. 2.5 and plus for the detail:
> >
> > 28.6 EFI HTTP Protocols
> >
> 
> Without reviewing patches themselves - we usually prefer to rely on
> firmware as little as possible. We already have HTTP support, so what
> is missing in grub that requires what amounts to full
> re-implementation? Cannot we rather fix our HTTP support instead? This
> will automatically benefit all supported platforms, of which EFI is
> just one.

Nothing wrong in providing firmware based approach in addition to grub's native
stack of getting the similar things done. And there's no prioity for what has
to be implemented first imho. Occasionally people would prefer firmware based
stack because they need new features it provides that haven't been worked out
in grub, such as the https or fibre networks, or simply to avoid bug from grub,
like the SNP woes among some UEFI box.

Thanks,
Michael

> 
> > Then why two implementations? For older UEFI firmwares (UEFI 2.4 and older),
> > the HTTP(s) APIs are not available. In the case,
> > Grub can fall back to the software-based implementation.
> > In the first patch of this patchset, grub-core/net/drivers/efi/efihttp.c:76 to 81
> > is the code to query if the HTTP Protocol is supported by the UEFI firmware.
> >
> > This patchset was tested on QEMU+OVMF and it works flawlessly.
> >
> > The main goals of this RFC is to ask for opinions and suggestion to make
> > the first patch modularized as much as possible.
> > In the second patch, there is some codes related TCP re-transmission
> > that need to pass by for the HTTP Boot to work.
> >
> > More details are described in the logs of each patch.
> >
> >
> > Ken Lin (2):
> >   net: add efihttp to do HTTP(S) Boot by UEFI HTTP Protocol
> >   net: workaround to bypass corruption of the efihttp function pointer
> >
> >  grub-core/Makefile.core.def         |   1 +
> >  grub-core/net/bootp.c               |   6 +
> >  grub-core/net/drivers/efi/efihttp.c | 386 ++++++++++++++++++++++++++++++++++++
> >  grub-core/net/drivers/efi/efinet.c  |   1 +
> >  grub-core/net/net.c                 |  39 +++-
> >  include/grub/efi/api.h              |  17 ++
> >  include/grub/efi/http.h             | 221 +++++++++++++++++++++
> >  include/grub/err.h                  |   3 +-
> >  include/grub/net.h                  |   1 +
> >  9 files changed, 672 insertions(+), 3 deletions(-)
> >  create mode 100755 grub-core/net/drivers/efi/efihttp.c
> >  create mode 100755 include/grub/efi/http.h
> >
> > --
> > 2.7.4
> >
> >
> > _______________________________________________
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> > Grub-devel@gnu.org
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> 
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