From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: is kexec on Xen domU possible? Date: Fri, 19 Jul 2013 13:58:05 -0700 Message-ID: <51E9A85D.2060206@zytor.com> References: <20130719020603.GA22932@kroah.com> <20130719131819.GC11233@debian70-amd64.local.net-space.pl> <20130719151243.GA15488@kroah.com> <20130719183235.GA12267@debian70-amd64.local.net-space.pl> <20130719191449.GA1882@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130719191449.GA1882@kroah.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Greg KH Cc: xen-devel@lists.xensource.com, Konrad Rzeszutek Wilk , Daniel Kiper , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Eric Biederman , Brandon Philips List-Id: xen-devel@lists.xenproject.org On 07/19/2013 12:14 PM, Greg KH wrote: >> >>> The errors that the kexec tools seem to run into is finding the memory >>> to place the new kernel into, is that just an issue that PV guests >>> aren't given enough kernel memory in which to replicate themselves from >>> dom0? >> >> There are a lot of differences between baremetal machines and PV guests. >> For example you are not able to do identity mapping per se in PV guests. >> Arguments to new kernel are passed in completely different way. etc. > > Ok, thanks for confirming that it is possible, but doesn't currently > work for pv guests. > Also, in any virtualized environment the hypervisor can do a better job for things like kdump, simply because it can provide two things that are otherwise hard to do: 1. a known-good system state; 2. a known-clean kdump image. As such, I do encourage the virtualization people to (also) develop hypervisor-*aware* solutions for these kinds of things. -hpa