From mboxrd@z Thu Jan 1 00:00:00 1970 From: Samuel Thibault Subject: Re: Bootstrap in mini-os Date: Fri, 27 Jun 2008 14:47:07 +0100 Message-ID: <20080627134707.GA4433@implementation.uk.xensource.com> References: <7F0FB2108857B5449321AEA91CF47903185A6F6F68@hkgmail01.lsi.com> <20080626224933.GG4628@implementation> <7F0FB2108857B5449321AEA91CF47903185A6D8784@hkgmail01.lsi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <7F0FB2108857B5449321AEA91CF47903185A6D8784@hkgmail01.lsi.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: "Jayaraman, Bhaskar" Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Jayaraman, Bhaskar, le Fri 27 Jun 2008 20:50:24 +0800, a =E9crit : > 1] Since the bootstrap page tables are marked read-only we have our sta= rt_pfn after it? Yes. > 2] The domain loader will load the Mini-OS at pseudo physical page 0? All PV kernels are always loaded at PFN 0. Then PFNs are mapped at the virtual address set in the ELF notes. > 3] I didn't understand how does deducting &_text give a physical addres= s, Because _text is always at PFN 0. > since the start pfn is to begin after pt_base and not at pseudo physica= l address 0. _text is not at start_pfn. start_pfn is _after_ all the day0 layout, i.e. the kernel code, the bootstrap page table etc. > What I'm saying is what difference will it make if we don't deduct the = text pseudo physical address? It does make a difference if somebody, for some reason, wants to have the mini-os kernel virtually start at e.g. 0xc0000000. It will still pseudo-physically start at 0. > 4] If I'm right the shared_info pte is overwritten by the hypervisor wi= th the shared_info struct that we pass it and relocated to another mfn in= the mfn_list with the hypercall? However, Mini-os will still keep referr= ing to shared_info at pseudo physical page at offset 0x1000 or the 1st ps= eudo physical frame? Currently the PFN numbered 1 is not available from mini-os, because it is "overmapped" by the shared info page. Samuel