From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: pyxc_linux_build() in tools/python/xen/lowlevel/xc/xc.c still needed? Date: Tue, 6 Oct 2015 10:32:52 +0100 Message-ID: <56139544.3000108@citrix.com> References: <56136B21.1030704@suse.com> <1444121781.5302.52.camel@citrix.com> <56139044.9030300@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <56139044.9030300@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: =?windows-1252?Q?Roger_Pau_Monn=E9?= , Ian Campbell , Juergen Gross , "xen-devel@lists.xen.org" , Konrad Rzeszutek Wilk Cc: Ian Jackson , Wei Liu , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On 06/10/15 10:11, Roger Pau Monn=E9 wrote: > El 06/10/15 a les 10.56, Ian Campbell ha escrit: >> On Tue, 2015-10-06 at 08:33 +0200, Juergen Gross wrote: >>> Do we have any requirements to be compatible to old releases regarding >>> the functions in tools/python/xen/lowlevel/xc/xc.c ? >> IMHO, no. >> >> There are also too many compatibility shims in front of the domain build= er, >> i.e. all the stuff in tools/libxc/xc_dom_compat_linux.c which IMHO could= be >> nuked too. >> >>> Especially pyxc_linux_build() isn't used anywhere in the tree. And this >>> is the only function setting xc_dom_image.superpages, thus removing it >>> would give us the chance to remove some code of the domain builder. >> Right. = >> >> Removing the superpages option from the non-Python might cause concern f= or >> some. Adding Konrad since IIRC PV superpages is a thing Oracle implement= ed >> and might still care about. >> >> Also adding Roger since he is reworking the HVM builder to use the PV on= e, >> which for all I know might involve using the superpage option (but proba= bly >> not the PV code to set it up). > The superpages field is only used to populate memory of PV domains, > AFAICT HVM domains will already try to use superpages by default in > order to fill the p2m. I don't have any problem with it being removed. There is a key difference between PV guests and HVM guests when it comes to superpages. A PV guest needs to be explicitly capable of handling superpages, and it rules out things like migrate, etc. HVM superpages are just EPT/NPT superpages, without a direct effect on guest. I don't object to removing this field, but mistakenly equate PV and HVM guests in this regard. ~Andrew