Re: [PATCH] xen/pvh: Indicate XENFEAT_linux_rsdp_unrestricted to Xen

[Boris Ostrovsky]

On 04/09/2018 02:51 PM, Boris Ostrovsky wrote:
> Pre-4.17 kernels ignored start_info's rsdp_paddr pointer and instead
> relied on finding RSDP in standard location in BIOS RO memory. This
> has worked since that's where Xen used to place it.
>
> However, with recent Xen change (commit 4a5733771e6f ("libxl: put RSDP
> for PVH guest near 4GB")) it prefers to keep RSDP at a "non-standard"
> address. Even though as of commit b17d9d1df3c3 ("x86/xen: Add pvh
> specific rsdp address retrieval function") Linux is able to find RSDP,
> for back-compatibility reasons we need to indicate to Xen that we can
> handle this, an we do so by setting XENFEAT_linux_rsdp_unrestricted
> flag in ELF notes.
>
> (Also take this opportunity and sync features.h header file with Xen)
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>



Committed to for-linus-4.17.

-boris