From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v4.2] libxc: Defer initialization of start_page for HVM guests Date: Fri, 8 Jan 2016 09:19:27 -0500 Message-ID: <568FC56F.3050209@oracle.com> References: <1452205147-6320-1-git-send-email-boris.ostrovsky@oracle.com> <568F41B1.9070205@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <568F41B1.9070205@suse.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: Juergen Gross , ian.jackson@eu.citrix.com, stefano.stabellini@eu.citrix.com, ian.campbell@citrix.com, wei.liu2@citrix.com Cc: andrew.cooper3@citrix.com, roger.pau@citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 01/07/2016 11:57 PM, Juergen Gross wrote: > On 07/01/16 23:19, Boris Ostrovsky wrote: >> With commit 8c45adec18e0 ("libxc: create unmapped initrd in domain >> builder if supported") location of ramdisk may not be available to >> HVMlite guests by the time alloc_magic_pages_hvm() is invoked if the >> guest supports unmapped initrd. >> >> So let's move ramdisk info initialization (along with a few other >> operations that are not directly related to allocating magic/special >> pages) from alloc_magic_pages_hvm() to bootlate_hvm(). >> >> Since we now split allocation and mapping of the start_info segment >> let's stash it, along with cmdline length, in xc_dom_image so that we >> can check whether we are mapping correctly-sized range. >> >> We can also stop using xc_dom_image.start_info_pfn and leave it for >> PV(H) guests only. >> >> Signed-off-by: Boris Ostrovsky >> --- >> v4: >> * See the last two paragraphs from commit message above >> >> v4.1: >> * Inverted testing of start_info_size in bootlate_hvm(). >> >> v4.2 >> * Actually do what I said I'd do in 4.1 >> >> tools/libxc/include/xc_dom.h | 2 + >> tools/libxc/xc_dom_x86.c | 140 +++++++++++++++++++++++------------------ >> 2 files changed, 80 insertions(+), 62 deletions(-) >> >> diff --git a/tools/libxc/include/xc_dom.h b/tools/libxc/include/xc_dom.h >> index 2460818..cac4698 100644 >> --- a/tools/libxc/include/xc_dom.h >> +++ b/tools/libxc/include/xc_dom.h >> @@ -71,6 +71,7 @@ struct xc_dom_image { >> >> /* arguments and parameters */ >> char *cmdline; >> + size_t cmdline_size; >> uint32_t f_requested[XENFEAT_NR_SUBMAPS]; >> >> /* info from (elf) kernel image */ >> @@ -91,6 +92,7 @@ struct xc_dom_image { >> struct xc_dom_seg p2m_seg; >> struct xc_dom_seg pgtables_seg; >> struct xc_dom_seg devicetree_seg; >> + struct xc_dom_seg start_info_seg; /* HVMlite only */ > Instead of adding HVM specific members here, you could make use of > dom.arch_private and use just a local structure defined in xc_dom_x86.c. I did consider this but since we already keep type-specific segments in this structure (e.g. p2m_seg) decided to add an explicit segment for HVMlite. Besides, I think to properly use it we'd need to add an arch hook and IMHO it's not worth the trouble in this case. -boris