Re: [SeaBIOS] [Qemu-devel] [PATCH RFC 2/3] acpi: load and link tables from /etc/acpi/

[Laszlo Ersek]

Not sure how much it counts, but I personally can agree with you on this
direction :)

One note below:
> @@ -603,8 +604,72 @@ acpi_setup(void)
>      if (! CONFIG_ACPI)
>          return;
>
> int acpi_generate = 1;
>
> dprintf(3, "init ACPI tables\n");
>
> struct romfile_s *file = NULL;
>
> for (;;) {
>    file = romfile_findprefix("/etc/acpi/", file);
>    if (!file)
>        break;
>    /*
>     * Disable ACPI table generation. All ACPI tables must come from
>     * etc/acpi/ romfile entries.
>     */
>    acpi_generate = 0;

[...]
> }
> linker_link("/etc/linker-script");
> if (!acpi_generate) {
>    return;
> }
> dprintf(3, "generate ACPI tables\n");
> // This code is hardcoded for PIIX4 Power Management device.
>    struct pci_device *pci = pci_find_init_device(acpi_find_tbl, NULL);
>    if (!pci)

Are you deliberately calling linker_link() independently from
"acpi_generate"? My hunch is that linker_link() only makes sense if
acpi_generate == 0 (ie. qemu has passed down at least one table to
repoint some pointer to), but I may be missing a use case.

Thanks
Laszlo

[Qemu-devel] [PATCH RFC 2/3] acpi: load and link tables from /etc/acpi/

[Michael S. Tsirkin]

On Mon, Apr 29, 2013 at 01:41:01PM +0200, Laszlo Ersek wrote:
> Not sure how much it counts, but I personally can agree with you on this
> direction :)
>
> One note below:
> > @@ -603,8 +604,72 @@ acpi_setup(void)
> >      if (! CONFIG_ACPI)
> >          return;
> >
> > int acpi_generate = 1;
> >
> > dprintf(3, "init ACPI tables\n");
> >
> > struct romfile_s *file = NULL;
> >
> > for (;;) {
> >    file = romfile_findprefix("/etc/acpi/", file);
> >    if (!file)
> >        break;
> >    /*
> >     * Disable ACPI table generation. All ACPI tables must come from
> >     * etc/acpi/ romfile entries.
> >     */
> >    acpi_generate = 0;
>
> [...]
> > }
> > linker_link("/etc/linker-script");
> > if (!acpi_generate) {
> >    return;
> > }
> > dprintf(3, "generate ACPI tables\n");
> > // This code is hardcoded for PIIX4 Power Management device.
> >    struct pci_device *pci = pci_find_init_device(acpi_find_tbl, NULL);
> >    if (!pci)
>
> Are you deliberately calling linker_link() independently from
> "acpi_generate"? My hunch is that linker_link() only makes sense if
> acpi_generate == 0 (ie. qemu has passed down at least one table to
> repoint some pointer to), but I may be missing a use case.
>
> Thanks
> Laszlo

In theory linker code is unrelated to acpi, and host
can the linker to patch any romfile.
I could add if (!acpi_generate) but it just seems
like adding code to remove something potentially useful.