Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters

From	Daniel Kiper <daniel.kiper@oracle.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters
Date	2015-09-14 14:30 +0200
Message-ID	<q8B3s-66v-23@gated-at.bofh.it> (permalink)
References	(5 earlier) <q7cTx-6MC-41@gated-at.bofh.it> <q7vWa-1Oz-21@gated-at.bofh.it> <q7zn3-6Xj-3@gated-at.bofh.it> <q7RtD-7R3-11@gated-at.bofh.it> <q8yfh-254-29@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Mon, Sep 14, 2015 at 10:25:19AM +0100, Mark Rutland wrote:
> On Sat, Sep 12, 2015 at 12:36:55PM +0100, Daniel Kiper wrote:
> > On Fri, Sep 11, 2015 at 05:25:59PM +0100, Mark Rutland wrote:
> > > On Fri, Sep 11, 2015 at 01:46:43PM +0100, Daniel Kiper wrote:
> > > > On Thu, Sep 10, 2015 at 05:23:02PM +0100, Mark Rutland wrote:
> >
> > [...]
> >
> > > > > What's troublesome with the boot services?
> > > > >
> > > > > What can't be simulated?
> > > >
> > > > How do you want to access bare metal EFI boot services from dom0 if they
> > > > were shutdown long time ago before loading dom0 image?
> > >
> > > I don't want to.
> > >
> > > I asked "What can't be simulated?" because I assumed everything
> > > necessary/mandatory could be simulated without needinng access to any
> > > real EFI boot services.
> > >
> > > As far as I can see all that's necessary is to provide a compatible
> > > interface.
> >
> > Could you be more precise what do you need? Please enumerate. UEFI spec has
> > more than 2500 pages and I do not think that we need all stuff in dom0.
> >
> > > > What do you need from EFI boot services in dom0?
> > >
> > > The ability to call ExitBootServices() and SetVirtualAddressMap() on a
> > > _virtual_ address map for _virtual_ services provided by the hypervisor.
> >
> > I am confused. Why do you need that? Please remember, EFI is owned and
> > operated by Xen hypervisor. dom0 does not have direct access to EFI.
>
> Let's take a step back.
>
> My objection here is to passing the Dom0 kernel properties as if it were
> booted with direct access to a full UEFI, then later fixing that up
> (when Xen is detected and we apply its hypercall EFI implementation).
>
> If the kernel cannot use EFI natively, why pretend to the kernel that it
> can? The hypercall implementation is _not_ EFI (though it provides
> access to some services).
>
> The two ways I can see providing Dom0 with EFI services are:
>
> * Have Xen create shims for any services, in which any hypercalls live,
>   and pass these to the kernel with a virtual system table. This keeps
>   the interface to the kernel the same regardless of Xen.
>
> * Have the kernel detect Xen EFI capability via Xen, without passing the
>   usual native EFI parameters. This can then be installed into the
>   kernel in a Xen-specific manner, and we know from the outset that
>   Xen-specific caveats apply.

It works on x86 in that way and I suppose that it can work in that way on ARM too.
So, just go and reuse existing code. That is all.

Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Thread

[PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Shannon Zhao <zhaoshenglong@huawei.com> - 2015-09-10 11:00 +0200
  Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 12:00 +0200
    Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-10 12:30 +0200
      Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 13:30 +0200
        Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-10 13:50 +0200
          Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 14:20 +0200
            Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of  EFI stub parameters Ian Campbell <ian.campbell@citrix.com> - 2015-09-10 15:00 +0200
              Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names  of EFI stub parameters "Jan Beulich" <JBeulich@suse.com> - 2015-09-10 15:10 +0200
                Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of  EFI stub parameters Ian Campbell <ian.campbell@citrix.com> - 2015-09-10 15:40 +0200
            Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-10 16:00 +0200
              Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Leif Lindholm <leif.lindholm@linaro.org> - 2015-09-10 16:20 +0200
              Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 16:50 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-10 18:20 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 18:30 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Daniel Kiper <daniel.kiper@oracle.com> - 2015-09-11 14:50 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-11 15:20 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-11 15:40 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Daniel Kiper <daniel.kiper@oracle.com> - 2015-09-11 17:50 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Shannon Zhao <zhaoshenglong@huawei.com> - 2015-09-14 11:00 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-14 11:10 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Shannon Zhao <zhaoshenglong@huawei.com> - 2015-09-14 11:40 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-14 11:40 +0200
                Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names  of EFI stub parameters "Jan Beulich" <JBeulich@suse.com> - 2015-09-14 12:40 +0200
                Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of EFI  stub parameters Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-14 13:20 +0200
                Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names  of EFI stub parameters "Jan Beulich" <JBeulich@suse.com> - 2015-09-14 13:40 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-11 18:40 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-11 18:30 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Daniel Kiper <daniel.kiper@oracle.com> - 2015-09-12 13:50 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-14 11:30 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2015-09-14 11:50 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Daniel Kiper <daniel.kiper@oracle.com> - 2015-09-14 14:30 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Ian Campbell <ian.campbell@citrix.com> - 2015-09-11 13:10 +0200
          Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters "Jan Beulich" <JBeulich@suse.com> - 2015-09-10 15:00 +0200
            Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-10 17:00 +0200
              Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters "Jan Beulich" <JBeulich@suse.com> - 2015-09-10 17:10 +0200
                Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Mark Rutland <mark.rutland@arm.com> - 2015-09-11 18:40 +0200
  Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Andrew Turner <andrew@fubar.geek.nz> - 2015-09-10 13:50 +0200
    Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Julien Grall <julien.grall@citrix.com> - 2015-09-10 13:50 +0200
      Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub  parameters Roger Pau Monné <roger.pau@citrix.com> - 2015-09-10 14:10 +0200
        Re: [Xen-devel] [PATCH] efi/libstub/fdt: Standardize the names of  EFI stub parameters Julien Grall <julien.grall@citrix.com> - 2015-09-10 15:00 +0200
  Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Shannon Zhao <zhaoshenglong@huawei.com> - 2015-09-17 14:00 +0200

csiph-web