From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: [PATCH v5 6/9] libxc: create unmapped initrd in domain builder if supported Date: Mon, 30 Nov 2015 13:20:13 +0100 Message-ID: <565C3EFD.40208@suse.com> References: <1447335816-31772-1-git-send-email-jgross@suse.com> <1447335816-31772-7-git-send-email-jgross@suse.com> <5655DDDC.5000005@oracle.com> <5656B626.6080305@suse.com> <20151130102002.GF21588@citrix.com> <565C23A6.4080707@suse.com> <1448879699.15768.14.camel@citrix.com> <565C2946.60109@suse.com> <1448880697.15768.17.camel@citrix.com> <1448880756.15768.18.camel@citrix.com> <565C2D10.9060203@suse.com> <1448882606.15768.21.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1448882606.15768.21.camel@citrix.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 , Wei Liu Cc: Boris Ostrovsky , roger.pau@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On 30/11/15 12:23, Ian Campbell wrote: > On Mon, 2015-11-30 at 12:03 +0100, Juergen Gross wrote: >> On 30/11/15 11:52, Ian Campbell wrote: >>> On Mon, 2015-11-30 at 10:51 +0000, Ian Campbell wrote: >>>> On Mon, 2015-11-30 at 11:47 +0100, Juergen Gross wrote: >>>>> On 30/11/15 11:34, Ian Campbell wrote: >>>>>> On Mon, 2015-11-30 at 11:23 +0100, Juergen Gross wrote: >>>>>>> On 30/11/15 11:20, Wei Liu wrote: >>>>>>>> On Thu, Nov 26, 2015 at 08:35:02AM +0100, Juergen Gross >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> /* initrd parameters as specified in start_info page >>>>>>>>> */ >>>>>>>>> - unsigned long initrd_start; >>>>>>>>> - unsigned long initrd_len; >>>>>>>>> + uint64_t initrd_start; >>>>>>>>> + uint64_t initrd_len; >>>>>>>>> >>>>>>>> >>>>>>>> I think these should be of type xen_vaddr_t. Doesn't make a >>>>>>>> difference >>>>>>>> in the end though. >>>>>>> >>>>>>> xen_vaddr_t seems not to be appropriate. It can be either a >>>>>>> virtual >>>>>>> address or a pfn. >>>>>> >>>>>> Did you mean a virtual address or a physical _address_? >>>>>> Potentially >>>>>> mixing >>>>>> addresses and frame numbers in a single variable seems liable to >>>>>> be >>>>>> confusing, at best. >>>>> >>>>> No, it's really a pfn. And this is part of the stable interface >>>>> between >>>>> hypervisor and the pv-domU since more than 5 years now. >>>> >>>> Including the virtual address bit? >>>> >>>> That's a shame. >>> >>> ... and that being the case would you mind adding a comment here >>> explaining >>> the two forms of these variables and the flag which indicates which one >>> is >>> "in force" at a given moment. >> >> The comment in the struct already tells us that initrd_start and >> initrd_len are in the very same format as in the start_info page. >> Both fields are meant to be opaque to most of the domain builder >> parts. >> >> The only function dealing with the differences is xc_dom_build_image() >> which already contains the appropriate flag. I added this on your >> request. You acked the resulting patch. So why do you want to add >> another comment now? > > I hadn't realised at the time that the semantics of these fields was so, > uh, interesting. :-) I guess due to the lack of a comment? ;-) Okay, I'll add one when submitting the patch after (hopefully) Boris confirmed it is fixing his problem. Juergen