linux-kernel - Re: [PATCH v3 02/11] x86/kexec: Add extra pointers to transition page table PGD, PUD, PMD and PTE

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Date:	Mon, 7 Jan 2013 13:52:11 +0100
From:	Daniel Kiper <daniel.kiper@...cle.com>
To:	Jan Beulich <JBeulich@...e.com>
Cc:	andrew.cooper3@...rix.com, x86@...nel.org, tglx@...utronix.de,
	kexec@...ts.infradead.org,
	virtualization@...ts.linux-foundation.org,
	xen-devel <xen-devel@...ts.xen.org>, konrad.wilk@...cle.com,
	maxim.uvarov@...cle.com, mingo@...hat.com, vgoyal@...hat.com,
	linux-kernel@...r.kernel.org, ebiederm@...ssion.com, hpa@...or.com
Subject: Re: [PATCH v3 02/11] x86/kexec: Add extra pointers to transition
 page table PGD, PUD, PMD and PTE

On Mon, Jan 07, 2013 at 09:48:20AM +0000, Jan Beulich wrote:
> >>> On 04.01.13 at 18:25, Daniel Kiper <daniel.kiper@...cle.com> wrote:
> > Right, so where is virtual mapping of control page established?
> > I could not find relevant code in SLES kernel which does that.
>
> In the hypervisor (xen/arch/x86/machine_kexec.c:machine_kexec_load()).
> xen/arch/x86/machine_kexec.c:machine_kexec() then simply uses
> image->page_list[1].

This (xen/arch/x86/machine_kexec.c:machine_kexec_load()) maps relevant
page (allocated earlier by dom0) in hypervisor fixmap area. However,
it does not make relevant mapping in transition page table which
leads to crash when %cr3 is switched from Xen page table to
transition page table.

Daniel
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