From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: state of guest at start-up Date: Wed, 04 Apr 2007 10:49:39 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Max Dmitrichenko , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 4/4/07 09:46, "Max Dmitrichenko" wrote: > 1) What are the status of event channels mask at the start of the day? > My experiments showed that all the event channels are unmasked - is > this right? In the sources of Mini-OS, I have found a comment saying > that event channels are masked at the start. But this seems to be > obsolete, or do I make something wrong? The vcpu_info[cpu].evtchn_upcall_mask fields are all set to 1. This prevents upcalls on all vcpus. The per-event-channel masks (shared_info.evtchn_mask) is initialised to all zeroes. > 2) What is the meaning of shared_info.vcpu_info[0].evtchn_upcall_mask? > I thought that it masks all the event channels on the VCPU #0, but > this seems wrong, i.e. when I set this to 0xff, the hypervisor > callback is still being called. I have to set the > shared_info.evtchn_mask to all ones in order to mask all the event > channels. Is this behavour correct? No. vcpu_info[cpu].evtchn_upcall_mask definitely stops callbacks via the hypervisor_callback. > 3) How to determine current VCPU number? As you would if running natively -- probably by stack-pointer arithmetic and have some per-cpu info stashed at the bottom of the stack page. > 4) When I map the shared_info MFN into my OS's space via > update_va_mapping hypercall and then take the dump of the domain with > `xm dump-core -C ...`, the page where the shared_info supposed to be > mapped to is filled with all zeroes. Is this normal, of that means > that mapping was unsuccessful. If you don't include the shared_info page in your phys-to-machine map then dump-core will not dump the page contents. -- Keir