From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tian, Kevin" Subject: Re: (v2) Design proposal for RMRR fix Date: Mon, 19 Jan 2015 11:24:41 +0000 Message-ID: References: <54B515E6020000780005444A@mail.emea.novell.com> <54B54D48020000780005473E@mail.emea.novell.com> <54B540AA.1010905@eu.citrix.com> <54B63E250200007800054A36@mail.emea.novell.com> <54B651EE0200007800054ADD@mail.emea.novell.com> <54B65AB4.5060504@eu.citrix.com> <54B68C180200007800054E84@mail.emea.novell.com> <54B67F32.8050902@eu.citrix.com> <54B68FA10200007800054F01@mail.emea.novell.com> <54B6B578.60106@eu.citrix.com> <54B78A5A02000078000552C2@mail.emea.novell.com> <54BCDD53020000780005645A@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <54BCDD53020000780005645A@mail.emea.novell.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: "wei.liu2@citrix.com" , "ian.campbell@citrix.com" , "stefano.stabellini@eu.citrix.com" , George Dunlap , "tim@xen.org" , "ian.jackson@eu.citrix.com" , "xen-devel@lists.xen.org" , "Zhang, Yang Z" , "Chen, Tiejun" List-Id: xen-devel@lists.xenproject.org > From: Jan Beulich [mailto:JBeulich@suse.com] > Sent: Monday, January 19, 2015 5:33 PM > > >>> On 18.01.15 at 09:58, wrote: > > still one open to hear suggestion though, regarding to how we want > > to pass the reserved regions to domain builder and hvmloader (for Xen > > we will extend related assignment hypercall to include per device override). > > > > one simple solution is to extend xc_hvm_build_args and hvm_info_table > > to include specified regions, with the limitation on defining a fixed > > number (possibly use E820_MAX as a reasonable assumption) > > As said (in other contexts?) a couple of times recently - I think we > should try to avoid altering struct hvm_info_table if at all possible. > It should really only be used for information that cannot be passed > by any other means between the involved components. yes, I should add this note when describing that option. Just want to put what's discussed before in the table. > > > another option is to place the information in xenstore which is more > > flexible. However domain builder doesn't use xenstore right now (suppose > > extending use xenstore is not complex?) > > > > or any other thought to be evaluated? > > What's wrong with attaching them to the domain with a domctl, and > having a suitable "normal" hypercall (along the lines of > XENMEM_reserved_device_memory_map, just that this one would > need to be domain specific) for the domain (including hvmloader) to > retrieve it? > definitely it's not wrong. I meant to include this option but looks it got missed when sending the mail. Using hypercall is similarly to use xenstore (just matter where to centrally save the information). Originally I thought people may think user space option is more flexible. But now since using xenstore has dependency problem, let's go with this hypercall option. so in a summary two new hypercalls will be added: one general to allow libxl query per-device RMRR, and then the other domain specific to allow libxl specifying reserved regions. Thanks Kevin