From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757567Ab2ECQ1c (ORCPT ); Thu, 3 May 2012 12:27:32 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:54807 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756157Ab2ECQ1b (ORCPT ); Thu, 3 May 2012 12:27:31 -0400 X-IronPort-AV: E=Sophos;i="4.75,524,1330923600"; d="scan'208";a="193271122" Message-ID: <4FA2B1EF.8080900@citrix.com> Date: Thu, 3 May 2012 17:27:27 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20120317 Icedove/3.0.11 MIME-Version: 1.0 To: "xen-devel@lists.xensource.com" CC: Konrad Rzeszutek Wilk , "linux-kernel@vger.kernel.org" , "JBeulich@suse.com" Subject: Re: [Xen-devel] [PATCH] auto balloon initial domain and fix dom0_mem=X inconsistencies (v5). References: <1334596539-18172-1-git-send-email-konrad.wilk@oracle.com> <20120501163707.GA8741@phenom.dumpdata.com> <4FA27084.4030005@citrix.com> <4FA2A11E.1060907@cantab.net> In-Reply-To: <4FA2A11E.1060907@cantab.net> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/05/12 16:15, David Vrabel wrote: > > xen: update VA mapping when releasing memory during setup > > In xen_memory_setup(), if a page that is being released has a VA > mapping this must also be updated. Otherwise, the page will be not > released completely -- it will still be referenced in Xen and won't be > freed util the mapping is removed and this prevents it from being > reallocated at a different PFN. > > This was already being done for the ISA memory region in > xen_ident_map_ISA() but on many systems this was omitting a few pages > as many systems marked a few pages below the ISA memory region as > reserved in the e820 map. > > Signed-off-by: David Vrabel > --- [...] > --- a/arch/x86/xen/mmu.c > +++ b/arch/x86/xen/mmu.c > @@ -1929,29 +1929,6 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) > #endif > } > > -void __init xen_ident_map_ISA(void) > -{ > - unsigned long pa; > - > - /* > - * If we're dom0, then linear map the ISA machine addresses into > - * the kernel's address space. > - */ > - if (!xen_initial_domain()) > - return; It might look like this test has gone, however the new code which updates the VA mapping uses the e820 map and for a domU its map will not have a ISA region so there's no mapping to be updated. David > - > - xen_raw_printk("Xen: setup ISA identity maps\n"); > - > - for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) { > - pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO); > - > - if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0)) > - BUG(); > - } > - > - xen_flush_tlb(); > -} > - > static void __init xen_post_allocator_init(void) > { > pv_mmu_ops.set_pte = xen_set_pte; > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c > index 506a3e6..d5f8714 100644 > --- a/arch/x86/xen/setup.c > +++ b/arch/x86/xen/setup.c > @@ -139,6 +139,13 @@ static unsigned long __init xen_do_chunk(unsigned long start, > > return len; > } > + > +static unsigned long __init xen_release_chunk(unsigned long start, > + unsigned long end) > +{ > + return xen_do_chunk(start, end, true); > +} > + > static unsigned long __init xen_populate_chunk( > const struct e820entry *list, size_t map_size, > unsigned long max_pfn, unsigned long *last_pfn, > @@ -197,6 +204,29 @@ static unsigned long __init xen_populate_chunk( > } > return done; > } > + > +static void __init xen_set_identity_and_release_chunk( > + unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages, > + unsigned long *released, unsigned long *identity) > +{ > + unsigned long pfn; > + > + /* > + * If the PFNs are currently mapped, the VA mapping also needs > + * to be updated to be 1:1. > + */ > + for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) > + (void)HYPERVISOR_update_va_mapping( > + (unsigned long)__va(pfn << PAGE_SHIFT), > + mfn_pte(pfn, PAGE_KERNEL_IO), 0); > + > + if (start_pfn < nr_pages) > + *released += xen_release_chunk( > + start_pfn, min(end_pfn, nr_pages)); > + > + *identity += set_phys_range_identity(start_pfn, end_pfn); > +} > + > static unsigned long __init xen_set_identity_and_release( > const struct e820entry *list, size_t map_size, unsigned long nr_pages) > { > @@ -226,14 +256,11 @@ static unsigned long __init xen_set_identity_and_release( > if (entry->type == E820_RAM) > end_pfn = PFN_UP(entry->addr); > > - if (start_pfn < end_pfn) { > - if (start_pfn < nr_pages) > - released += xen_do_chunk( > - start_pfn, min(end_pfn, nr_pages), true); > + if (start_pfn < end_pfn) > + xen_set_identity_and_release_chunk( > + start_pfn, end_pfn, nr_pages, > + &released, &identity); > > - identity += set_phys_range_identity( > - start_pfn, end_pfn); > - } > start = end; > } > } > diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h > index b095739..506fa08 100644 > --- a/arch/x86/xen/xen-ops.h > +++ b/arch/x86/xen/xen-ops.h > @@ -28,7 +28,6 @@ void xen_setup_shared_info(void); > void xen_build_mfn_list_list(void); > void xen_setup_machphys_mapping(void); > pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn); > -void xen_ident_map_ISA(void); > void xen_reserve_top(void); > extern unsigned long xen_max_p2m_pfn; >