From patchwork Fri Feb 7 15:57:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 11370723 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4F48D14BC for ; Fri, 7 Feb 2020 15:58:25 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 136E4214AF for ; Fri, 7 Feb 2020 15:58:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="tAc7SRrN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 136E4214AF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j060M-0002fS-Ev; Fri, 07 Feb 2020 15:57:18 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j060K-0002fN-MK for xen-devel@lists.xenproject.org; Fri, 07 Feb 2020 15:57:16 +0000 X-Inumbo-ID: 7fb42400-49c2-11ea-a759-bc764e2007e4 Received: from merlin.infradead.org (unknown [2001:8b0:10b:1231::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 7fb42400-49c2-11ea-a759-bc764e2007e4; Fri, 07 Feb 2020 15:57:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description; bh=WPhbpHbnEi5ph9YnLzAFjSxiRDYKFToUxDKb8RkGn+8=; b=tAc7SRrNumbZplqo3GVKefObwX droLuEPS+itAmSnY9OQIQnZfURhGZrQhoOB1pTtG37OG7dSYMoUUAJWGBpQ8l2z3vMCgzkCEUxvlc Z4q4gP7vBPQRaqrZxB/X9FhMs2H16GIdMgqpt7CFyQ7HSFVgYFh4PHw9Ba5mIO9iWVjJDsmi33cQM sIqLXR+8G0CJz2ZSy55xaKnZ8Q0lh9vnuVaHElaG7M8oSBqMTUAplDWFhGn0moesir/4pVcQowUZQ J0pnIGHPGubQUyaeR8kBeB3CtnUB8/GpHj2V1JlGfW/JWhN1ep6Nw8rZ3UidNEQcrQTrrlE8s9Vsl 7xVbZg2g==; Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j0606-0003ck-5P; Fri, 07 Feb 2020 15:57:02 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1j0605-00Bfgn-BK; Fri, 07 Feb 2020 15:57:01 +0000 From: David Woodhouse To: Jan Beulich Date: Fri, 7 Feb 2020 15:57:01 +0000 Message-Id: <20200207155701.2781820-2-dwmw2@infradead.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <56f7fe21daff2dc4bf8db7ee356666233bdb0f7a.camel@infradead.org> References: <56f7fe21daff2dc4bf8db7ee356666233bdb0f7a.camel@infradead.org> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Subject: [Xen-devel] [PATCH 2/2] xen/mm: Introduce PG_state_uninitialised X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , George Dunlap , Jeff Kubascik , Stewart Hildebrand , xen-devel@lists.xenproject.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: David Woodhouse It is possible for pages to enter general circulation without ever being process by init_heap_pages(). For example, pages of the multiboot module containing the initramfs may be assigned via assign_pages() to dom0 as it is created. And some code including map_pages_to_xen() has checks on 'system_state' to determine whether to use the boot or the heap allocator, but it seems impossible to prove that pages allocated by the boot allocator are not subsequently freed with free_heap_pages(). This actually works fine in the majority of cases; there are only a few esoteric corner cases which init_heap_pages() handles before handing the page range off to free_heap_pages(): • Excluding MFN #0 to avoid inappropriate cross-zone merging. • Ensuring that the node information structures exist, when the first page(s) of a given node are handled. • High order allocations crossing from one node to another. To handle this case, shift PG_state_inuse from its current value of zero, to another value. Use zero, which is the initial state of the entire frame table, as PG_state_uninitialised. Fix a couple of assertions which were assuming that PG_state_inuse is zero, and make them cope with the PG_state_uninitialised case too where appopriate. Finally, make free_xenheap_pages() and free_domheap_pages() call through to init_heap_pages() instead of directly to free_heap_pages() in the case where pages are being free which have never passed through init_heap_pages(). Signed-off-by: David Woodhouse Signed-off-by: David Woodhouse --- xen/arch/x86/mm.c | 3 ++- xen/common/page_alloc.c | 41 ++++++++++++++++++++++++++-------------- xen/include/asm-arm/mm.h | 3 ++- xen/include/asm-x86/mm.h | 3 ++- 4 files changed, 33 insertions(+), 17 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 9b33829084..bf660ee8eb 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -488,7 +488,8 @@ void share_xen_page_with_guest(struct page_info *page, struct domain *d, page_set_owner(page, d); smp_wmb(); /* install valid domain ptr before updating refcnt. */ - ASSERT((page->count_info & ~PGC_xen_heap) == 0); + ASSERT((page->count_info & ~PGC_xen_heap) == PGC_state_inuse || + (page->count_info & ~PGC_xen_heap) == PGC_state_uninitialised); /* Only add to the allocation list if the domain isn't dying. */ if ( !d->is_dying ) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 4084503554..9703a2c664 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1407,6 +1407,7 @@ static void free_heap_pages( switch ( pg[i].count_info & PGC_state ) { case PGC_state_inuse: + case PGC_state_uninitialised: pg[i].count_info = PGC_state_free; break; @@ -1780,11 +1781,10 @@ int query_page_offline(mfn_t mfn, uint32_t *status) * latter is not on a MAX_ORDER boundary, then we reserve the page by * not freeing it to the buddy allocator. */ -static void init_heap_pages( - struct page_info *pg, unsigned long nr_pages) +static void init_heap_pages(struct page_info *pg, unsigned long nr_pages, + bool scrub) { unsigned long i; - bool idle_scrub = false; /* * Keep MFN 0 away from the buddy allocator to avoid crossing zone @@ -1809,7 +1809,7 @@ static void init_heap_pages( spin_unlock(&heap_lock); if ( system_state < SYS_STATE_active && opt_bootscrub == BOOTSCRUB_IDLE ) - idle_scrub = true; + scrub = true; for ( i = 0; i < nr_pages; i++ ) { @@ -1837,7 +1837,7 @@ static void init_heap_pages( nr_pages -= n; } - free_heap_pages(pg + i, 0, scrub_debug || idle_scrub); + free_heap_pages(pg + i, 0, scrub_debug || scrub); } } @@ -1873,7 +1873,7 @@ void __init end_boot_allocator(void) if ( (r->s < r->e) && (phys_to_nid(pfn_to_paddr(r->s)) == cpu_to_node(0)) ) { - init_heap_pages(mfn_to_page(_mfn(r->s)), r->e - r->s); + init_heap_pages(mfn_to_page(_mfn(r->s)), r->e - r->s, false); r->e = r->s; break; } @@ -1882,7 +1882,7 @@ void __init end_boot_allocator(void) { struct bootmem_region *r = &bootmem_region_list[i]; if ( r->s < r->e ) - init_heap_pages(mfn_to_page(_mfn(r->s)), r->e - r->s); + init_heap_pages(mfn_to_page(_mfn(r->s)), r->e - r->s, false); } nr_bootmem_regions = 0; @@ -2151,7 +2151,7 @@ void init_xenheap_pages(paddr_t ps, paddr_t pe) memguard_guard_range(maddr_to_virt(ps), pe - ps); - init_heap_pages(maddr_to_page(ps), (pe - ps) >> PAGE_SHIFT); + init_heap_pages(maddr_to_page(ps), (pe - ps) >> PAGE_SHIFT, false); } @@ -2174,14 +2174,20 @@ void *alloc_xenheap_pages(unsigned int order, unsigned int memflags) void free_xenheap_pages(void *v, unsigned int order) { + struct page_info *pg; ASSERT(!in_irq()); if ( v == NULL ) return; + pg = virt_to_page(v); + memguard_guard_range(v, 1 << (order + PAGE_SHIFT)); - free_heap_pages(virt_to_page(v), order, false); + if ( unlikely(page_state_is(pg, uninitialised)) ) + init_heap_pages(pg, 1 << order, true); + else + free_heap_pages(pg, order, false); } #else /* !CONFIG_SEPARATE_XENHEAP */ @@ -2237,7 +2243,10 @@ void free_xenheap_pages(void *v, unsigned int order) for ( i = 0; i < (1u << order); i++ ) pg[i].count_info &= ~PGC_xen_heap; - free_heap_pages(pg, order, true); + if ( unlikely(page_state_is(pg, uninitialised)) ) + init_heap_pages(pg, 1 << order, true); + else + free_heap_pages(pg, order, true); } #endif /* CONFIG_SEPARATE_XENHEAP */ @@ -2260,7 +2269,7 @@ void init_domheap_pages(paddr_t ps, paddr_t pe) if ( mfn_x(emfn) <= mfn_x(smfn) ) return; - init_heap_pages(mfn_to_page(smfn), mfn_x(emfn) - mfn_x(smfn)); + init_heap_pages(mfn_to_page(smfn), mfn_x(emfn) - mfn_x(smfn), false); } @@ -2301,10 +2310,11 @@ int assign_pages( for ( i = 0; i < (1 << order); i++ ) { ASSERT(page_get_owner(&pg[i]) == NULL); - ASSERT(!pg[i].count_info); + ASSERT(pg[i].count_info == PGC_state_inuse || + pg[i].count_info == PGC_state_uninitialised); page_set_owner(&pg[i], d); smp_wmb(); /* Domain pointer must be visible before updating refcnt. */ - pg[i].count_info = PGC_allocated | 1; + pg[i].count_info |= PGC_allocated | 1; page_list_add_tail(&pg[i], &d->page_list); } @@ -2427,7 +2437,10 @@ void free_domheap_pages(struct page_info *pg, unsigned int order) scrub = 1; } - free_heap_pages(pg, order, scrub); + if ( unlikely(page_state_is(pg, uninitialised)) ) + init_heap_pages(pg, 1 << order, scrub); + else + free_heap_pages(pg, order, scrub); } if ( drop_dom_ref ) diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h index c9466c8ca0..c696941600 100644 --- a/xen/include/asm-arm/mm.h +++ b/xen/include/asm-arm/mm.h @@ -117,12 +117,13 @@ struct page_info * { inuse, offlining, offlined, free, broken_offlining, broken } */ #define PGC_state PG_mask(7, 9) -#define PGC_state_inuse PG_mask(0, 9) +#define PGC_state_uninitialised PG_mask(0, 9) #define PGC_state_offlining PG_mask(1, 9) #define PGC_state_offlined PG_mask(2, 9) #define PGC_state_free PG_mask(3, 9) #define PGC_state_broken_offlining PG_mask(4, 9) #define PGC_state_broken PG_mask(5, 9) +#define PGC_state_inuse PG_mask(6, 9) #define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st) #define page_is_broken(pg) (page_state_is((pg), broken_offlining) || \ diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h index 3edadf7a7c..645368e6a9 100644 --- a/xen/include/asm-x86/mm.h +++ b/xen/include/asm-x86/mm.h @@ -72,12 +72,13 @@ * { inuse, offlining, offlined, free, broken_offlining, broken } */ #define PGC_state PG_mask(7, 9) -#define PGC_state_inuse PG_mask(0, 9) +#define PGC_state_uninitialised PG_mask(0, 9) #define PGC_state_offlining PG_mask(1, 9) #define PGC_state_offlined PG_mask(2, 9) #define PGC_state_free PG_mask(3, 9) #define PGC_state_broken_offlining PG_mask(4, 9) #define PGC_state_broken PG_mask(5, 9) +#define PGC_state_inuse PG_mask(6, 9) #define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st) #define page_is_broken(pg) (page_state_is((pg), broken_offlining) || \