From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH 1/6] docs: update docs for the ~/platform/generation-id key Date: Wed, 28 May 2014 15:51:33 +0100 Message-ID: <5385F7F5.5080409@citrix.com> References: <1401211909-27771-1-git-send-email-david.vrabel@citrix.com> <1401211909-27771-2-git-send-email-david.vrabel@citrix.com> <1401288261.10916.7.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WpfCd-00020L-7o for xen-devel@lists.xenproject.org; Wed, 28 May 2014 14:51:39 +0000 In-Reply-To: <1401288261.10916.7.camel@kazak.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, Ian Jackson , David Vrabel , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On 28/05/14 15:44, Ian Campbell wrote: > On Tue, 2014-05-27 at 18:31 +0100, David Vrabel wrote: >> Signed-off-by: David Vrabel >> --- >> docs/misc/xenstore-paths.markdown | 24 ++++++++++++++++-------- >> 1 file changed, 16 insertions(+), 8 deletions(-) >> >> diff --git a/docs/misc/xenstore-paths.markdown b/docs/misc/xenstore-paths.markdown >> index 70ab7f4..41d7d6d 100644 >> --- a/docs/misc/xenstore-paths.markdown >> +++ b/docs/misc/xenstore-paths.markdown >> @@ -166,11 +166,6 @@ use the xenstore-based protocol instead (see ~/control/shutdown, >> below) even if the guest has advertised support for the event channel >> protocol. >> >> -#### ~/hvmloader/generation-id-address = ADDRESS [r,HVM,INTERNAL] >> - >> -The hexadecimal representation of the address of the domain's >> -"generation id". >> - >> #### ~/hvmloader/allow-memory-relocate = ("1"|"0") [HVM,INTERNAL] >> >> If the default low MMIO hole (below 4GiB) is not big enough for all >> @@ -193,9 +188,22 @@ Various platform properties. >> >> #### ~/platform/generation-id = INTEGER ":" INTEGER [HVM,INTERNAL] >> >> -Two 64 bit values that represent the Windows Generation ID. >> -Is used by the BIOS initializer to get this value. >> -If not present or "0:0" (all zeroes) device will not be present to the machine. >> +The upper and lower 64-bit words of the 128-bit VM Generation ID. >> + >> +This key is used by hvmloader to create the ACPI VM Generation ID >> +device. It initialises a 16 octet region of guest memory with this >> +value. The guest physical address of this region is saved in the >> +HVM_PARAM_VM_GENERATION_ID_ADDR HVM parameter. >> + >> +If this key is not present, is empty, or is all-zeros ("0:0") then the >> +ACPI device is not created. >> + >> +The toolstack should, before unpausing a created or restored HVM >> +domain, set this key and write the same ID to the guest memory >> +location in HVM_PARAM_VM_GENERATION_ID_ADDR (if this address is >> +non-zero). > Is the toolstack or hvmloader now responsible for writing this value to > guest memory? It seems like it might be a shared responsibility via some > mode of cooperation that I'm not following? > > Ian. HVMLoader is responsible for allocating the space inside the guest to start with, and for populating it with the initial value. However, HVMLoader is *not* rerun on suspend/resume, so something external in the toolstack needs to be able to update the value when needed. ~Andrew