[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI
From: |
Mark Rutland |
Subject: |
Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation |
Date: |
Tue, 11 Nov 2014 16:48:07 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Hi Christoffer,
On Tue, Nov 11, 2014 at 04:31:01PM +0000, Christoffer Dall wrote:
> On Tue, Nov 11, 2014 at 03:29:33PM +0000, Mark Rutland wrote:
> > Hi,
> >
> > On Thu, Nov 06, 2014 at 01:33:20PM +0000, Alexander Spyridakis wrote:
> > > On 6 November 2014 14:44, Peter Maydell <address@hidden> wrote:
> > > >
> > > >
> > > > > We need ACPI guest support in QEMU for AArch64 over here, with all
> > > > > features
> > > > > (including the ability to run ACPI code and add specific tables), for
> > > > > ACPI-based guests.
> > > >
> > > > The plan for providing ACPI to guests is that we run a UEFI BIOS
> > > > blob which is what is responsible for providing ACPI and UEFI
> > > > runtime services to guests which need them. (The UEFI blob finds
> > > > out about its hardware by looking at a device tree that QEMU
> > > > passes it, but that's a detail between QEMU and its bios blob).
> > > > This pretty much looks like what x86 QEMU used to do with ACPI
> > > > for a very long time, so we know it's a feasible approach.
> > >
> > > Hi Peter,
> > >
> > > The rational in the proposed approach is meant for cases where the
> > > user does not want to rely on external firmware layers. While UEFI
> > > could do what you are describing, the point is to avoid this not so
> > > trivial overhead in the booting process. Especially in the case of
> > > thin guests, where another software dependency is undesired.
> >
> > I'm not sure how you plan to use ACPI without UEFI, as there are several
> > pieces of information which ACPI misses, such as the memory map, which
> > must be discovered from UEFI. How do you intend to discover the memory
> > map without UEFI?
> >
> > Additionally, with Linux and other generic OSs, the expectation is that
> > the ACPI tables are discovered via the UEFI system table. How do you
> > intend to discover the ACPI tables? Or other system information?
>
> FWIW, Xen needs to pass the RDSP pointer along with a tiny DT containing
> the command line and memory information to Dom0 as well.
When you say "memory information", is that pointers to a UEFI memory
map, or memory nodes? The former should work for ACPI, but I don't think
the latter will. I think there's a need for some discussion regarding
the Dom0 boot flow for ACPI. Is there any tree I can take a peek at?
Passing just the RDSP will mean that Dom0 won't get SMBIOS tables and
other potentially useful things, in addition to simply being yet another
potential boot configuration. I'm a little concerned about that.
> We are currently suggesting adding an RDSP property to the chosen node
> in the tiny DT, but a command-line arguement like kexec proposed could
> be another option I guess, albeit not a very pretty one.
I'm not sure what an RDSP command line property would have to do with
kexec. I'll assume I've misunderstood something.
> But, what I hear from Huawei is that they don't want any DT and don't
> want any UEFI, so not sure how they plan on accomplishing that.
Indeed.
Thanks,
Mark.
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Claudio Fontana, 2014/11/05
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Peter Maydell, 2014/11/06
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Igor Mammedov, 2014/11/06
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Alexander Spyridakis, 2014/11/06
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Peter Maydell, 2014/11/06
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Mark Rutland, 2014/11/11
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Christoffer Dall, 2014/11/11
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation,
Mark Rutland <=
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Christoffer Dall, 2014/11/11
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Mark Rutland, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Christoffer Dall, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Mark Rutland, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Graeme Gregory, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Julien Grall, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Paolo Bonzini, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Mark Rutland, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Paolo Bonzini, 2014/11/12
- Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation, Peter Maydell, 2014/11/12