Messages in this thread |  | | Subject | Re: [PATCH 2/8] x86/head: Refactor 32-bit pgtable setup | From | Boris Ostrovsky <> | Date | Fri, 14 Oct 2016 14:44:18 -0400 |
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On 10/14/2016 02:31 PM, hpa@zytor.com wrote: > On October 14, 2016 11:05:12 AM PDT, Boris Ostrovsky <boris.ostrovsky@oracle.com> wrote: >> From: Matt Fleming <matt@codeblueprint.co.uk> >> >> The new Xen PVH entry point requires page tables to be setup by the >> kernel since it is entered with paging disabled. >> >> Pull the common code out of head_32.S and into pgtable_32.S so that >> setup_pgtable_32 can be invoked from both the new Xen entry point and >> the existing startup_32 code. >> > And why does it need a separate entry point as opposed to the plain one?
One reason is that we need to prepare boot_params before jumping to startup_{32|64}.
When the guest is loaded (always in 32-bit mode) the only thing we have is a pointer to Xen-specific datastructure. The early PVH code will prepare zeropage based on that structure and then jump to regular startup_*() code.
-boris
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