From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:39012) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RIgxx-0001zN-Ux for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:22:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RIgxw-0003DF-Uz for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:22:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34942) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RIgxw-0003D5-Nt for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:22:52 -0400 Message-ID: <4EA6B820.7010003@redhat.com> Date: Tue, 25 Oct 2011 15:22:40 +0200 From: Avi Kivity MIME-Version: 1.0 References: <1b1504e0-bdc0-4c5c-8c65-38eed168ac17@zmail05.collab.prod.int.phx2.redhat.com> In-Reply-To: <1b1504e0-bdc0-4c5c-8c65-38eed168ac17@zmail05.collab.prod.int.phx2.redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Dave Anderson Cc: "Richard W.M. Jones" , Jan Kiszka , qemu-devel , Luiz Capitulino , Paolo Bonzini , KAMEZAWA Hiroyuki On 10/25/2011 03:18 PM, Dave Anderson wrote: > > > > Crash uses a heuristic based on the IDT base to identify the base from > > migrate-to-file output. It also needs CR3 in order to read from virtual > > address. > > Just to clarify -- the need for the IDT base and cr3 is *only* true for > KVM dumps using the "savevm" format. > > With ELF-format kdumps, the phys_base is simply determined from the PT_LOAD > segment that describes the kernel's __START_KERNEL_map region. I don't know > why that couldn't be done in this proposed case. > > kvm has no idea where the kernel (if any) is running. The dump is taken without any guest cooperation. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.