Re: [Qemu-devel] [PATCH v2] Add ACPI tables for TPM

[Stefan Berger]

"Michael S. Tsirkin" <address@hidden>
wrote on 07/30/2014 11:07:28 AM:


> > >If you need bios to allocate this memory, then we will
> > >need a new allocation type for this, add it to linker
> > >in bios and qemu.
> > 
> > Why does the BIOS 'need' to allocate it? Why can it not just
use the memory
> > that QEMU allocates? Obviously I am using the 'pointer relocation'
feature
> > of the BIOS to bend the pointer in the TCPA table to this log
area.
> 
> You tell me - your patches make BIOS allocate it.

No, the BIOS does not allocate it, it merely relocates
the pointer.

One example here:

    fadt->firmware_ctrl = cpu_to_le32(facs);
    /* FACS address to be filled by Guest
linker */
    bios_linker_loader_add_pointer(linker,
ACPI_BUILD_TABLE_FILE,  
               
                   ACPI_BUILD_TABLE_FILE,
               
                   table_data,
&fadt->firmware_ctrl,
               
                   sizeof
fadt->firmware_ctrl);

similar example here:

    log_area_start_address = table_data->len
+ sizeof(*tcpa);
 
    [...]
    tcpa->log_area_start_address = cpu_to_le64(log_area_start_address);

    /* LASA address to be filled by Guest
linker */
    bios_linker_loader_add_pointer(linker,
ACPI_BUILD_TABLE_FILE,
               
                   ACPI_BUILD_TABLE_FILE,
               
                   table_data,
&tcpa->log_area_start_address,
               
                   sizeof(tcpa->log_area_start_address));



   Stefan