Re: [Xen-devel] [PATCH][HVMLOADER][DISCUSS] 8 way default rombios

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 7 Jun 2006, at 05:55, Wang, Winston L wrote:

> Here is my suggestion for you:
> If you want to add SMP support for MPS table, you need to check HVM
> guest configuration file for the switches for acpi and vcpu =number:
>
>    if (vcpu !=1 &acpi=0)
>      build xen-(vcpu number)-way-bios
>      ...
> Just as Jun pointed out  MPS table is used for old guest OS (plug and
> play mode +APM) mode, not for ACPI,
The best way would be to do the same as the for our ACPI tables -- 
dynamically generate the CPU entries (LAPIC entries in case of ACPI 
tables) when we know how many VCPUs the guest has been allocated.
This would get rid of multiple statically-compiled rombios images, each 
of which only differs in CPU info in the MPS table. It could even be 
hacked up without modifying rombios image -- e.g., hvmloader could scan 
for and then modify the MPS table to insert secondary-processor 
entries. It wouldn't be very hard to do.
In any case, I'll revert the earlier patch. Using a MPS table that 
advertises 8 processors when a guest actually has fewer doesn't seem a 
very wise idea.
 -- Keir


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