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Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support |
Date: |
Tue, 09 Jun 2015 02:08:03 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 06/08/15 20:14, Michael S. Tsirkin wrote:
> XSDT support allows using ACPI 2 features while
> avoiding breaking legacy windows XP guests:
> ACPI 2 tables are linked from XSDT only,
> ACPI 1 tables from both RSDT and XSDT, this way
> XP does not see ACPI 2 tables.
>
> As a first step, this patchset generates v2 RSDP
> and fills in XSDT matching RSDT exactly.
>
> ARM can switch to XSDT as well, I'm not bothering
> until there's an easy way to test that.
>
> Note: unit test files need to be updated with this,
> I'm not bothering with posting them.
>
> Changes from v1:
> xsdt address is 64 bit
> arm patch is now tested
>
> Michael S. Tsirkin (4):
> acpi: add API for 64 bit offsets
> i386/acpi: collect 64 bit offsets for xsdt
> i386/acpi: add XSDT
> acpi: unify rsdp generation
>
> include/hw/acpi/acpi-defs.h | 15 +++++--
> include/hw/acpi/aml-build.h | 7 +++-
> hw/acpi/aml-build.c | 99
> +++++++++++++++++++++++++++++++++++++--------
> hw/arm/virt-acpi-build.c | 39 +++---------------
> hw/i386/acpi-build.c | 64 +++++++++++------------------
> 5 files changed, 129 insertions(+), 95 deletions(-)
>
I tested this series with ArmVirtQemu (aka AAVMF) and OVMF too. (They
use common code in edk2.)
The ARM build works indeed, but that's only because in patch #4 we have
build_rsdp(tables->rsdp, tables->linker, rsdt, 0);
ie. there's only an RSDT.
Due to patch #3 however, the OVMF client breaks:
build_rsdp(tables->rsdp, tables->linker, rsdt, xsdt);
The problem is that the "directed acyclic graph" of ADD_POINTER edges is
no longer a tree. At least some tables can be reached on multiple paths.
(Eg. the FADT can be reached via RSDP->RSDT-> FADT, and also
RSDP->XSDT->FADT.)
This is a problem because EFI_ACPI_TABLE_PROTOCOL has "builtin
knowledge" about what tables may not be installed only once vs. several
times. Unfortunately, in this case both decisions have bad consequences:
- When FADT is passed to EFI_ACPI_TABLE_PROTOCOL.InstallAcpiTable() for
the second time, the function returns EFI_ACCESS_DENIED, and the
linker/loader client bails out.
- When (eg.) the same SSDT is passed to
EFI_ACPI_TABLE_PROTOCOL.InstallAcpiTable() for the second time, the
function will happily install (a copy of) it again, and then we'll end
up with two copies of the same SSDT.
EFI_ACPI_TABLE_PROTOCOL manages both the RSDT and the XSDT internally.
As far as I can see, it puts each table in both. The RSDT and the XSDT
are not distinguished even on the UEFI spec level; it lumps them
together under "RSDT/XSDT" every time.
This is probably very frustrating; sorry about that.
Laszlo
- [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/08
- [Qemu-devel] [PATCH v2 1/4] acpi: add API for 64 bit offsets, Michael S. Tsirkin, 2015/06/08
- [Qemu-devel] [PATCH v2 2/4] i386/acpi: collect 64 bit offsets for xsdt, Michael S. Tsirkin, 2015/06/08
- [Qemu-devel] [PATCH v2 3/4] i386/acpi: add XSDT, Michael S. Tsirkin, 2015/06/08
- [Qemu-devel] [PATCH v2 4/4] acpi: unify rsdp generation, Michael S. Tsirkin, 2015/06/08
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support,
Laszlo Ersek <=
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Paolo Bonzini, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Laszlo Ersek, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Laszlo Ersek, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Igor Mammedov, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] acpi: xsdt support, Michael S. Tsirkin, 2015/06/09