From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752709Ab3LTDK3 (ORCPT ); Thu, 19 Dec 2013 22:10:29 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:49570 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750896Ab3LTDK1 (ORCPT ); Thu, 19 Dec 2013 22:10:27 -0500 Date: Wed, 18 Dec 2013 15:30:37 -0500 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, david.vrabel@citrix.com, mukesh.rathor@oracle.com, jbeulich@suse.com Subject: Re: [Xen-devel] [PATCH v11 05/12] xen/pvh: Update E820 to work with PVH Message-ID: <20131218203037.GA9698@phenom.dumpdata.com> References: <1387313503-31362-1-git-send-email-konrad.wilk@oracle.com> <1387313503-31362-6-git-send-email-konrad.wilk@oracle.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 Wed, Dec 18, 2013 at 06:25:15PM +0000, Stefano Stabellini wrote: > On Tue, 17 Dec 2013, Konrad Rzeszutek Wilk wrote: > > From: Mukesh Rathor > > > > In xen_add_extra_mem() we can skip updating P2M as it's managed > > by Xen. PVH maps the entire IO space, but only RAM pages need > > to be repopulated. > > > > Signed-off-by: Mukesh Rathor > > Signed-off-by: Konrad Rzeszutek Wilk > > --- > > arch/x86/xen/setup.c | 19 +++++++++++++++++-- > > 1 file changed, 17 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c > > index 2137c51..f93bca1 100644 > > --- a/arch/x86/xen/setup.c > > +++ b/arch/x86/xen/setup.c > > @@ -27,6 +27,7 @@ > > #include > > #include > > #include > > +#include "mmu.h" > > #include "xen-ops.h" > > #include "vdso.h" > > > > @@ -81,6 +82,9 @@ static void __init xen_add_extra_mem(u64 start, u64 size) > > > > memblock_reserve(start, size); > > > > + if (xen_feature(XENFEAT_auto_translated_physmap)) > > + return; > > + > > xen_max_p2m_pfn = PFN_DOWN(start + size); > > for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) { > > unsigned long mfn = pfn_to_mfn(pfn); > > @@ -103,6 +107,7 @@ static unsigned long __init xen_do_chunk(unsigned long start, > > .domid = DOMID_SELF > > }; > > unsigned long len = 0; > > + int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap); > > unsigned long pfn; > > int ret; > > > > @@ -116,7 +121,7 @@ static unsigned long __init xen_do_chunk(unsigned long start, > > continue; > > frame = mfn; > > } else { > > - if (mfn != INVALID_P2M_ENTRY) > > + if (!xlated_phys && mfn != INVALID_P2M_ENTRY) > > continue; > > frame = pfn; > > } > > @@ -154,6 +159,13 @@ static unsigned long __init xen_do_chunk(unsigned long start, > > static unsigned long __init xen_release_chunk(unsigned long start, > > unsigned long end) > > { > > + /* > > + * Xen already ballooned out the E820 non RAM regions for us > > + * and set them up properly in EPT. > > + */ > > + if (xen_feature(XENFEAT_auto_translated_physmap)) > > + return end - start; > > + > > return xen_do_chunk(start, end, true); > > } > > > > @@ -222,6 +234,9 @@ static void __init xen_set_identity_and_release_chunk( > > * (except for the ISA region which must be 1:1 mapped) to > > * release the refcounts (in Xen) on the original frames. > > */ > > + if (xen_feature(XENFEAT_auto_translated_physmap)) > > + goto skip; > > + > > for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) { > > pte_t pte = __pte_ma(0); > > > > @@ -231,7 +246,7 @@ static void __init xen_set_identity_and_release_chunk( > > (void)HYPERVISOR_update_va_mapping( > > (unsigned long)__va(pfn << PAGE_SHIFT), pte, 0); > > } > > - > > +skip: > > if (start_pfn < nr_pages) > > *released += xen_release_chunk( > > start_pfn, min(end_pfn, nr_pages)); > > A goto? Really? What's wrong with an if? Moves too much code. > Also considering that you are turning xen_release_chunk into a nop, the > only purpose of this function on PVH is to call set_phys_range_identity. > Can't we just do that? And set_phys_range_identity ends up just doing: 769 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) 770 return pfn_e - pfn_s; So what we really could do (which is what Mukesh's patch had): if (xen_feature(XENFEAT..) { if (start_pfn < nr_pages) *released += min(end_pfn, nr_pages) - start_pfn; *identity += end_pfn - start_pfn; } in its own function. We could do that.