From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCHv9 0/9] Xen: extend kexec hypercall for use with pv-ops kernels Date: Tue, 5 Nov 2013 18:01:45 +0000 Message-ID: <52793289.8040808@citrix.com> References: <1381251310-29449-1-git-send-email-david.vrabel@citrix.com> <20131018184031.GA12658@router-fw-old.local.net-space.pl> <5261C0D0.4090606@cantab.net> <20131021121940.GY3626@debian70-amd64.local.net-space.pl> <52652469.2040703@citrix.com> <20131021202032.GE3626@debian70-amd64.local.net-space.pl> <52713A86.3050102@citrix.com> <52728C76.8040501@terremark.com> <5272A1C8.8070407@cantab.net> <20131031222148.GA15538@olila.local.net-space.pl> <20131105174109.GI15538@olila.local.net-space.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20131105174109.GI15538@olila.local.net-space.pl> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Daniel Kiper Cc: Keir Fraser , Don Slutz , xen-devel@lists.xen.org, David Vrabel , Jan Beulich , Daniel Kiper List-Id: xen-devel@lists.xenproject.org On 05/11/13 17:41, Daniel Kiper wrote: > On Thu, Oct 31, 2013 at 11:21:48PM +0100, Daniel Kiper wrote: >> On Thu, Oct 31, 2013 at 06:30:32PM +0000, David Vrabel wrote: >>> On 31/10/2013 16:59, Don Slutz wrote: > > [...] > >>>> A possible fix is attached as (0002...) this does allow me to get into >>>> the crash kernel. >>> >>> Thanks for tracking this down. This should be fixed in the tools by >>> correctly aligning that segment. > > With Don's patch (workaround) crash kernel works from time to time. > I hope that proper fix will solve this issue. > >> I have rebuild all binaries and results are the same. Configuration >> changes does not help too. Don's patches solve some issues but dump >> system still does not load (I use Linux Kernel 3.10.17). I can see >> only following messages in all cases: >> >> I'm in purgatory >> early console in decompress_kernel > > It looks that early VGA code touches VGA memory buffer (0xb8000). > When I mapped 0 - 1 MiB memory region (using machine_kexec_add_page() > in xen/arch/x86/machine_kexec.c:machine_kexec_load() everything > started working. So, sadly, I think we should map unconditionally > this memory region too. Thanks for tracking this down. Mapping all of 0 - 1 MiB seems reasonable to me, but this should be done by kexec-tools specifying this and not by Xen. I'll post updated Xen and kexec-tools patches tomorrow hopefully. David