From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCHEs]: support more than 32 VCPUs in guests Date: Mon, 14 Jun 2010 10:37:30 +0100 Message-ID: <4C15F85A.1050804@goop.org> References: <20100609160920.1445fbbe@mantra.us.oracle.com> <4C102742.3010108@goop.org> <20100609170825.06a67ff9@mantra.us.oracle.com> <4C1036B0.4060905@goop.org> <20100609191332.588a15d1@mantra.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100609191332.588a15d1@mantra.us.oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Mukesh Rathor Cc: "Xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 06/10/2010 03:13 AM, Mukesh Rathor wrote: > Well, BUG_ON is only triggered if booting more than 32 VCPUs on a *very > old* xen (pre xen 3.1.0). > > Looking at code closely, we could just set setup_max_cpus to 32 some > where in xen function, perhaps even in xen_vcpu_setup(). That way > later in smp_init() it would just be ok. > Yes. > One thing tho, the per cpus areas are already setup at that point, so that > would need to be cleaned. BTW, I don't understand why > have_vcpu_info_placement is set to 0 in xen_guest_init()? > xen_guest_init is used by the pvhvm path, and hvm domains don't have a notion of vcpu info placement. > What minimum version of xen is required to run pvops kernel? > In theory it should be back-compatible for all Xen 3, but in practice it tweaks lots of bugs in older Xens (particularly 32-on-64). I don't know that anyone has definitively established an earliest version. I implemented vcpu info placement for use in pvops kernels, but it was never my intention that it be an absolute requirement. J