Re: [Xen-devel] [PATCH v2 for-4.11] libxl: fix memory map reported to PVH guests

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Apr 20, 2018 at 03:57:19PM +0100, Roger Pau Monne wrote:
> PVH guests with 4GB of RAM or more get a memory map like the
> following:
> 
> 0x00000000000000 - 0x000000fee00000 RAM
> 0x000000fee00000 - 0x00000100000000 RESERVED
> 0x000000fc009000 - 0x000000fc009040 ACPI
> 0x000000fc000000 - 0x000000fc001000 ACPI
> 0x000000fc001000 - 0x000000fc009000 ACPI
> 0x00000100000000 - 0x000001fb200400 RAM
> 
> This is wrong because ACPI regions overlap with RAM regions. The cause
> of this issue is not setting a big enough MMIO hole and marking the
> whole MMIO hole as reserved, when it actually contains several pieces:
> 
>  - local APIC page.
>  - ACPI tables.
>  - HVM special pages.
> 
> Of those items only HVM special pages need to be marked as reserved in
> order to advise the guest against using them for example for memory
> hotplug.
> 
> After the fix the layout reported for the same guest is:
> 
> 0x00000000000000 - 0x000000fc000000 RAM
> 0x000000feff8000 - 0x000000ff000000 RESERVED
> 0x000000fc009000 - 0x000000fc009040 ACPI
> 0x000000fc000000 - 0x000000fc001000 ACPI
> 0x000000fc001000 - 0x000000fc009000 ACPI
> 0x00000100000000 - 0x000001fe000400 RAM
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>


Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>

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