From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753156Ab3LMPA6 (ORCPT ); Fri, 13 Dec 2013 10:00:58 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:27312 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753124Ab3LMPAz (ORCPT ); Fri, 13 Dec 2013 10:00:55 -0500 Date: Fri, 13 Dec 2013 09:59:37 -0500 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: Konrad Rzeszutek Wilk , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, george.dunlap@eu.citrix.com, ian.jackson@eu.citrix.com, mukesh.rathor@oracle.com, tim@xen.org, jbeulich@suse.com, boris.ostrovsky@oracle.com, david.vrabel@citrix.com Subject: Re: [PATCH V10 05/14] xen/pvh: balloon and grant changes. Message-ID: <20131213145937.GB4770@phenom.dumpdata.com> References: <1386900621-27528-1-git-send-email-konrad.wilk@oracle.com> <1386900621-27528-6-git-send-email-konrad.wilk@oracle.com> <20131213143620.GH2923@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 13, 2013 at 02:49:15PM +0000, Stefano Stabellini wrote: > On Fri, 13 Dec 2013, Konrad Rzeszutek Wilk wrote: > > On Fri, Dec 13, 2013 at 11:56:31AM +0000, Stefano Stabellini wrote: > > > On Thu, 12 Dec 2013, Konrad Rzeszutek Wilk wrote: > > > > From: Mukesh Rathor > > > > > > > > For balloon changes we skip setting of local P2M as it's updated > > > > in Xen. For grant, the shared grant frame is the PFN and not MFN, > > > > hence its mapped via the same code path as HVM. > > > > > > > > Signed-off-by: Mukesh Rathor > > > > [v1: Rebase on v3.7-rc3] > > > > Signed-off-by: Konrad Rzeszutek Wilk > > > > CC: > > > > Conflicts: > > > > drivers/xen/balloon.c > > > > [v2: Rebase on v3.13-rc3 has lot of ARM changes.] > > > > --- > > > > drivers/xen/balloon.c | 37 ++++++++++++++++++++----------------- > > > > drivers/xen/gntdev.c | 3 ++- > > > > drivers/xen/grant-table.c | 25 ++++++++++++++++++++++--- > > > > 3 files changed, 44 insertions(+), 21 deletions(-) > > > > > > > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > > > > index 55ea73f..0e9875a 100644 > > > > --- a/drivers/xen/balloon.c > > > > +++ b/drivers/xen/balloon.c > > > > @@ -354,7 +354,9 @@ static enum bp_state increase_reservation(unsigned long nr_pages) > > > > > > > > #ifdef CONFIG_XEN_HAVE_PVMMU > > > > /* Link back into the page tables if not highmem. */ > > > > - if (xen_pv_domain() && !PageHighMem(page)) { > > > > + if (xen_pv_domain() && !PageHighMem(page) && > > > > + !xen_feature(XENFEAT_auto_translated_physmap)) { > > > > + > > > > int ret; > > > > ret = HYPERVISOR_update_va_mapping( > > > > (unsigned long)__va(pfn << PAGE_SHIFT), > > > > @@ -411,28 +413,29 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) > > > > > > > > scrub_page(page); > > > > > > > > - /* > > > > - * Ballooned out frames are effectively replaced with > > > > - * a scratch frame. Ensure direct mappings and the > > > > - * p2m are consistent. > > > > - */ > > > > - scratch_page = get_balloon_scratch_page(); > > > > + if (!xen_feature(XENFEAT_auto_translated_physmap)) { > > > > + unsigned long p; > > > > + > > > > + /* > > > > + * Ballooned out frames are effectively replaced with > > > > + * a scratch frame. Ensure direct mappings and the > > > > + * p2m are consistent. > > > > + */ > > > > + scratch_page = get_balloon_scratch_page(); > > > > #ifdef CONFIG_XEN_HAVE_PVMMU > > > > - if (xen_pv_domain() && !PageHighMem(page)) { > > > > - ret = HYPERVISOR_update_va_mapping( > > > > - (unsigned long)__va(pfn << PAGE_SHIFT), > > > > - pfn_pte(page_to_pfn(scratch_page), > > > > + if (xen_pv_domain() && !PageHighMem(page)) { > > > > + ret = HYPERVISOR_update_va_mapping( > > > > + (unsigned long)__va(pfn << PAGE_SHIFT), > > > > + pfn_pte(page_to_pfn(scratch_page), > > > > PAGE_KERNEL_RO), 0); > > > > - BUG_ON(ret); > > > > - } > > > > + BUG_ON(ret); > > > > + } > > > > #endif > > > > - if (!xen_feature(XENFEAT_auto_translated_physmap)) { > > > > - unsigned long p; > > > > p = page_to_pfn(scratch_page); > > > > __set_phys_to_machine(pfn, pfn_to_mfn(p)); > > > > - } > > > > - put_balloon_scratch_page(); > > > > > > > > + put_balloon_scratch_page(); > > > > + } > > > > balloon_append(pfn_to_page(pfn)); > > > > } > > > > > > These changes to balloon.c are similar to my patch but: > > > > > > - they don't prevent set_phys_to_machine from being called by > > > increase_reservation for auto_translated guests > > > > > > > > > > - they don't prevent wasteful balloon_scratch_page from being allocated > > > for auto_translated guests > > > > > > > > > > I think that it would be best to take my patch instead. > > > > Lets focus the review on your patch then and have it part of this > > series. > > OK, but keep in mind that Xen on ARMv8 is currently broken without that > patch. Hm. We could have another patch to just disable BALLOON on ARMv8 :-) The question you have to ask - if your patch causes regression are you OK tracking/fixing it over the holidays :-) If yes, then yes - we can put that in v3.13-rc3 to make it work properly on ARMv8.