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Re: [Qemu-devel] [PATCH v2 3/5] acpi: pc: add fw_cfg device node to ssdt
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/5] acpi: pc: add fw_cfg device node to ssdt |
Date: |
Mon, 14 Sep 2015 17:16:44 -0300 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Mon, Sep 14, 2015 at 02:16:49PM -0400, Gabriel L. Somlo wrote:
> On Mon, Sep 14, 2015 at 01:09:41PM -0300, Eduardo Habkost wrote:
> > On Mon, Sep 14, 2015 at 10:57:31AM -0400, Gabriel L. Somlo wrote:
> > > Add a fw_cfg device node to the ACPI SSDT. While the guest-side
> > > BIOS can't utilize this information (since it has to access the
> > > hard-coded fw_cfg device to extract ACPI tables to begin with),
> > > having fw_cfg listed in ACPI will help the guest kernel keep a
> > > more accurate inventory of in-use IO port regions.
> > >
> > > Signed-off-by: Gabriel Somlo <address@hidden>
> > > ---
> > > hw/i386/acpi-build.c | 20 ++++++++++++++++++++
> > > 1 file changed, 20 insertions(+)
> > >
> > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > index 95e0c65..ecdb3a5 100644
> > > --- a/hw/i386/acpi-build.c
> > > +++ b/hw/i386/acpi-build.c
> > > @@ -1071,6 +1071,26 @@ build_ssdt(GArray *table_data, GArray *linker,
> > > aml_append(scope, aml_name_decl("_S5", pkg));
> > > aml_append(ssdt, scope);
> > >
> > > + if (guest_info->fw_cfg) {
> >
> > I sent a reply to v1 a few minutes before seeing v2. Copying it here for
> > reference:
> >
> > Is this function ever going to be called without fw_cfg set?
> > acpi_setup() returns immediately if fw_cfg isn't available.
>
> You're right, build_ssdt() is called from acpi_build(), which is
> called directly from acpi_setup(), and also indirectly via
> acpi_build_update() via acpi_add_rom_blob(), but all that eventually
> ties back to acpi_setup(), *after* it already established that
> guest_info->fw_cfg is non-NULL.
>
> > Also, this changes guest ABI, so you will need to add some compat flag
> > to PCMachineClass indicating if the device node should be added.
>
> So I'll replace the "if (guest_info->fw_cfg)" check with
> "if machine-type >= (pc-q35-2.5 or pc-i440fx-2.5))", in v3,
> as soon as the patches for the 2.5 machine type make it into
> git master (I remember seeing a reviewed-by fly by for that
> earlier today :)
Sounds good, assuming you are going to implement the "machine-type >= pc-2.5"
check with something like: PC_MACHINE_GET_CLASS(machine)->acpi_no_fw_cfg_node.
--
Eduardo
- [Qemu-devel] [PATCH v2 4/5] acpi: arm: add fw_cfg device node to dsdt, (continued)
[Qemu-devel] [PATCH v2 1/5] fw_cfg: expose control register size in fw_cfg.h, Gabriel L. Somlo, 2015/09/14
[Qemu-devel] [PATCH v2 5/5] fw_cfg: document ACPI device node information, Gabriel L. Somlo, 2015/09/14
[Qemu-devel] [PATCH v2 3/5] acpi: pc: add fw_cfg device node to ssdt, Gabriel L. Somlo, 2015/09/14
[Qemu-devel] [PATCH v2 2/5] pc: fw_cfg: move ioport base constant to pc.h, Gabriel L. Somlo, 2015/09/14