From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755544Ab3LRS0B (ORCPT ); Wed, 18 Dec 2013 13:26:01 -0500 Received: from smtp.citrix.com ([66.165.176.89]:44179 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750815Ab3LRS0A (ORCPT ); Wed, 18 Dec 2013 13:26:00 -0500 X-IronPort-AV: E=Sophos;i="4.95,508,1384300800"; d="scan'208";a="85857583" Date: Wed, 18 Dec 2013 18:25:15 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Konrad Rzeszutek Wilk CC: , , , , , Subject: Re: [Xen-devel] [PATCH v11 05/12] xen/pvh: Update E820 to work with PVH In-Reply-To: <1387313503-31362-6-git-send-email-konrad.wilk@oracle.com> Message-ID: References: <1387313503-31362-1-git-send-email-konrad.wilk@oracle.com> <1387313503-31362-6-git-send-email-konrad.wilk@oracle.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? 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?