From patchwork Wed Sep 16 12:20:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 11779665 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 952CE92C for ; Wed, 16 Sep 2020 12:21:48 +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 75E972223C for ; Wed, 16 Sep 2020 12:21:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75E972223C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass 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 4.92) (envelope-from ) id 1kIWQj-0007IB-UA; Wed, 16 Sep 2020 12:20:57 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kIWQi-0007I6-QB for xen-devel@lists.xenproject.org; Wed, 16 Sep 2020 12:20:56 +0000 X-Inumbo-ID: c501c399-02b5-4580-9473-2b4228f25496 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id c501c399-02b5-4580-9473-2b4228f25496; Wed, 16 Sep 2020 12:20:55 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 2C57BAEA2; Wed, 16 Sep 2020 12:21:10 +0000 (UTC) From: Jan Beulich Subject: [PATCH v4] EFI: free unused boot mem in at least some cases To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Wei Liu , Stefano Stabellini , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Lukasz Hawrylko References: <5dd2fcea-d8ec-1c20-6514-c7733b59047f@suse.com> Message-ID: Date: Wed, 16 Sep 2020 14:20:54 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <5dd2fcea-d8ec-1c20-6514-c7733b59047f@suse.com> Content-Language: en-US X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Address at least the primary reason why 52bba67f8b87 ("efi/boot: Don't free ebmalloc area at all") was put in place: Make xen_in_range() aware of the freed range. This is in particular relevant for EFI-enabled builds not actually running on EFI, as the entire range will be unused in this case. Signed-off-by: Jan Beulich Acked-by: Roger Pau Monné --- v4: Address PV shim breakage (stub function also needed adjustment). v3: Don't free the memory twice. v2: Also adjust the two places where comments point out that they need to remain in sync with xen_in_range(). Add assertions to xen_in_range(). --- The remaining issue could be addressed too, by making the area 2M in size and 2M-aligned. --- a/xen/arch/x86/efi/stub.c +++ b/xen/arch/x86/efi/stub.c @@ -52,6 +52,13 @@ bool efi_enabled(unsigned int feature) void __init efi_init_memory(void) { } +bool efi_boot_mem_unused(unsigned long *start, unsigned long *end) +{ + if ( start || end ) + *start = *end = (unsigned long)_end; + return false; +} + void efi_update_l4_pgtable(unsigned int l4idx, l4_pgentry_t l4e) { } bool efi_rs_using_pgtables(void) --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -830,6 +830,7 @@ void __init noreturn __start_xen(unsigne module_t *mod; unsigned long nr_pages, raw_max_page, modules_headroom, module_map[1]; int i, j, e820_warn = 0, bytes = 0; + unsigned long eb_start, eb_end; bool acpi_boot_table_init_done = false, relocated = false; int ret; struct ns16550_defaults ns16550 = { @@ -1145,7 +1146,8 @@ void __init noreturn __start_xen(unsigne /* * This needs to remain in sync with xen_in_range() and the - * respective reserve_e820_ram() invocation below. + * respective reserve_e820_ram() invocation below. No need to + * query efi_boot_mem_unused() here, though. */ mod[mbi->mods_count].mod_start = virt_to_mfn(_stext); mod[mbi->mods_count].mod_end = __2M_rwdata_end - _stext; @@ -1417,8 +1419,18 @@ void __init noreturn __start_xen(unsigne if ( !xen_phys_start ) panic("Not enough memory to relocate Xen\n"); + /* FIXME: Putting a hole in .bss would shatter the large page mapping. */ + if ( using_2M_mapping() ) + efi_boot_mem_unused(NULL, NULL); + /* This needs to remain in sync with xen_in_range(). */ - reserve_e820_ram(&boot_e820, __pa(_stext), __pa(__2M_rwdata_end)); + if ( efi_boot_mem_unused(&eb_start, &eb_end) ) + { + reserve_e820_ram(&boot_e820, __pa(_stext), __pa(eb_start)); + reserve_e820_ram(&boot_e820, __pa(eb_end), __pa(__2M_rwdata_end)); + } + else + reserve_e820_ram(&boot_e820, __pa(_stext), __pa(__2M_rwdata_end)); /* Late kexec reservation (dynamic start address). */ kexec_reserve_area(&boot_e820); @@ -1979,7 +1991,7 @@ int __hwdom_init xen_in_range(unsigned l paddr_t start, end; int i; - enum { region_s3, region_ro, region_rw, nr_regions }; + enum { region_s3, region_ro, region_rw, region_bss, nr_regions }; static struct { paddr_t s, e; } xen_regions[nr_regions] __hwdom_initdata; @@ -2004,6 +2016,14 @@ int __hwdom_init xen_in_range(unsigned l /* hypervisor .data + .bss */ xen_regions[region_rw].s = __pa(&__2M_rwdata_start); xen_regions[region_rw].e = __pa(&__2M_rwdata_end); + if ( efi_boot_mem_unused(&start, &end) ) + { + ASSERT(__pa(start) >= xen_regions[region_rw].s); + ASSERT(__pa(end) <= xen_regions[region_rw].e); + xen_regions[region_rw].e = __pa(start); + xen_regions[region_bss].s = __pa(end); + xen_regions[region_bss].e = __pa(&__2M_rwdata_end); + } } start = (paddr_t)mfn << PAGE_SHIFT; --- a/xen/arch/x86/tboot.c +++ b/xen/arch/x86/tboot.c @@ -1,3 +1,4 @@ +#include #include #include #include @@ -364,6 +365,8 @@ void tboot_shutdown(uint32_t shutdown_ty /* if this is S3 then set regions to MAC */ if ( shutdown_type == TB_SHUTDOWN_S3 ) { + unsigned long s, e; + /* * Xen regions for tboot to MAC. This needs to remain in sync with * xen_in_range(). @@ -378,6 +381,15 @@ void tboot_shutdown(uint32_t shutdown_ty /* hypervisor .data + .bss */ g_tboot_shared->mac_regions[2].start = (uint64_t)__pa(&__2M_rwdata_start); g_tboot_shared->mac_regions[2].size = __2M_rwdata_end - __2M_rwdata_start; + if ( efi_boot_mem_unused(&s, &e) ) + { + g_tboot_shared->mac_regions[2].size = + s - (unsigned long)__2M_rwdata_start; + g_tboot_shared->mac_regions[3].start = __pa(e); + g_tboot_shared->mac_regions[3].size = + (unsigned long)__2M_rwdata_end - e; + g_tboot_shared->num_mac_regions = 4; + } /* * MAC domains and other Xen memory --- a/xen/common/efi/ebmalloc.c +++ b/xen/common/efi/ebmalloc.c @@ -1,5 +1,6 @@ #include "efi.h" #include +#include #ifdef CONFIG_ARM /* @@ -21,7 +22,7 @@ static char __section(".bss.page_aligned") __aligned(PAGE_SIZE) ebmalloc_mem[EBMALLOC_SIZE]; -static unsigned long __initdata ebmalloc_allocated; +static unsigned long __read_mostly ebmalloc_allocated; /* EFI boot allocator. */ void __init *ebmalloc(size_t size) @@ -36,17 +37,37 @@ void __init *ebmalloc(size_t size) return ptr; } +bool efi_boot_mem_unused(unsigned long *start, unsigned long *end) +{ + if ( !start && !end ) + { + ebmalloc_allocated = sizeof(ebmalloc_mem); + return false; + } + + *start = (unsigned long)ebmalloc_mem + PAGE_ALIGN(ebmalloc_allocated); + *end = (unsigned long)ebmalloc_mem + sizeof(ebmalloc_mem); + + return *start < *end; +} + void __init free_ebmalloc_unused_mem(void) { -#if 0 /* FIXME: Putting a hole in the BSS breaks the IOMMU mappings for dom0. */ unsigned long start, end; - start = (unsigned long)ebmalloc_mem + PAGE_ALIGN(ebmalloc_allocated); - end = (unsigned long)ebmalloc_mem + sizeof(ebmalloc_mem); + if ( !efi_boot_mem_unused(&start, &end) ) + return; destroy_xen_mappings(start, end); + +#ifdef CONFIG_X86 + /* + * By reserving the space early in the E820 map, it gets freed way before + * we make it here. Don't free the range a 2nd time. + */ +#else init_xenheap_pages(__pa(start), __pa(end)); +#endif printk(XENLOG_INFO "Freed %lukB unused BSS memory\n", (end - start) >> 10); -#endif } --- a/xen/include/xen/efi.h +++ b/xen/include/xen/efi.h @@ -33,6 +33,7 @@ struct compat_pf_efi_runtime_call; bool efi_enabled(unsigned int feature); void efi_init_memory(void); +bool efi_boot_mem_unused(unsigned long *start, unsigned long *end); bool efi_rs_using_pgtables(void); unsigned long efi_get_time(void); void efi_halt_system(void);