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Re: [Xen-devel] Design doc of adding ACPI support for arm64 on Xen - version 5

On 2015/8/28 23:06, Jan Beulich wrote:
>>>> On 28.08.15 at 11:45, <zhaoshenglong@xxxxxxxxxx> wrote:
>> 2. Copy and change some EFI and ACPI tables
>> -------------------------------------------
>> a) Create EFI_SYSTEM_TABLE table
>> Copy the header from the origin and change the value of FirmwareVendor.
> Careful: The version in the header may imply that fields are there
> which you aren't aware of. I think you need to adjust the version
> field too. (Obviously along with FirmwareVendor you definitely also
> want to change FirmwareRevision.)

Ok, will change the FirmwareRevision as well.

>> Create only one ConfigurationTable to store VendorGuid and VendorTable.
> What do you mean with "Create only one ..." - there is only one.
> DYM "Create one additional Configuration Table entry ...", implying
> that the Configuration Table will need to by copied too?

Sorry for the misunderstanding. I mean that it doesn't copy the original
one and just creates a new ConfigurationTable.

>> d) Copy MADT table
>> It needs to change MADT table to restrict the number of vCPUs. We choose
>> to copy the first dom0_max_vcpus GICC entries of MADT to new created
>> MADT table when numa is not supported currently.
> Copy means you imply to have an original?

So I'll change it to "create".

> What if dom0_max_vcpus
> is larger than the physical CPU count?

I think it only needs to care the cpu_interface_number, uid and mpidr
field of GICC entry and other fields could be same with the host GICC
entry. It could get the mpidr from the vCPU index.

>> g) Copy RSDP table
>> Change the value of xsdt_physical_address in RSDP table. As we create a
>> new XSDT table and the address of XSDT is changed, so it needs to update
>> the value of "xsdt_physical_address" in RSDP. So Dom0 could get the
>> right XSDT table rather than the old one. And it needs to update the
>> value of VendorTable in EFI Configuration Table which is created in
>> above step a).
> How is this last sentence related to the handling of RSDP?

Because the ACPI root address(i.e. the address of RSDP table) is stored
in EFI Configuration Table.


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