From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1ZHC60-0005Us-P0 for mharc-grub-devel@gnu.org; Mon, 20 Jul 2015 10:31:08 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52514) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHC5x-0005Ns-BV for grub-devel@gnu.org; Mon, 20 Jul 2015 10:31:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZHC5r-00015v-9x for grub-devel@gnu.org; Mon, 20 Jul 2015 10:31:05 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:20983) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHC5q-000151-Sd for grub-devel@gnu.org; Mon, 20 Jul 2015 10:30:59 -0400 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t6KEUnc3010908 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 20 Jul 2015 14:30:50 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.13.8/8.13.8) with ESMTP id t6KEUnsD018358 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Mon, 20 Jul 2015 14:30:49 GMT Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0121.oracle.com (8.13.8/8.13.8) with ESMTP id t6KEUmDF032211; Mon, 20 Jul 2015 14:30:48 GMT Received: from olila.local.net-space.pl (/10.175.255.176) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 20 Jul 2015 07:30:48 -0700 From: Daniel Kiper To: xen-devel@lists.xenproject.org, grub-devel@gnu.org Subject: [PATCH v2 19/23] x86/efi: create new early memory allocator Date: Mon, 20 Jul 2015 16:29:14 +0200 Message-Id: <1437402558-7313-20-git-send-email-daniel.kiper@oracle.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1437402558-7313-1-git-send-email-daniel.kiper@oracle.com> References: <1437402558-7313-1-git-send-email-daniel.kiper@oracle.com> X-Source-IP: userv0021.oracle.com [156.151.31.71] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 141.146.126.69 Cc: jgross@suse.com, keir@xen.org, ian.campbell@citrix.com, andrew.cooper3@citrix.com, stefano.stabellini@eu.citrix.com, roy.franz@linaro.org, ning.sun@intel.com, david.vrabel@citrix.com, jbeulich@suse.com, phcoder@gmail.com, wei.liu2@citrix.com, qiaowei.ren@intel.com, richard.l.maliszewski@intel.com, gang.wei@intel.com, fu.wei@linaro.org X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Jul 2015 14:31:06 -0000 There is a problem with place_string() which is used as early memory allocator. It gets memory chunks starting from start symbol and going down. Sadly this does not work when Xen is loaded using multiboot2 protocol because start lives on 1 MiB address. So, I tried to use mem_lower address calculated by GRUB2. However, it works only on some machines. There are machines in the wild (e.g. Dell PowerEdge R820) which uses first ~640 KiB for boot services code or data... :-((( In case of multiboot2 protocol we need that place_string() only allocate memory chunk for EFI memory map. However, I think that it should be fixed instead of making another function used just in one case. I thought about two solutions. 1) We could use native EFI allocation functions (e.g. AllocatePool() or AllocatePages()) to get memory chunk. However, later (somewhere in __start_xen()) we must copy its contents to safe place or reserve this in e820 memory map and map it in Xen virtual address space. In later case we must also care about conflicts with e.g. crash kernel regions which could be quite difficult. 2) We may allocate memory area statically somewhere in Xen code which could be used as memory pool for early dynamic allocations. Looks quite simple. Additionally, it would not depend on EFI at all and could be used on legacy BIOS platforms if we need it. However, we must carefully choose size of this pool. We do not want increase Xen binary size too much and waste too much memory but also we must fit at least memory map on x86 EFI platforms. As I saw on small machine, e.g. IBM System x3550 M2 with 8 GiB RAM, memory map may contain more than 200 entries. Every entry on x86-64 platform is 40 bytes in size. So, it means that we need more than 8 KiB for EFI memory map only. Additionally, if we want to use this memory pool for Xen and modules command line storage (it would be used when xen.efi is executed as EFI application) then we should add, I think, about 1 KiB. In this case, to be on safe side, we should assume at least 64 KiB pool for early memory allocations, which is about 4 times of our earlier calculations. However, during discussion on Xen-devel Jan Beulich suggested that just in case we should use 1 MiB memory pool like it was in original place_string() implementation. So, let's use 1 MiB as it was proposed. If we think that we should not waste unallocated memory in the pool on running system then we can mark this region as __initdata and move all required data to dynamically allocated places somewhere in __start_xen(). Now solution #2 is implemented but maybe we should consider #1 one day. Signed-off-by: Daniel Kiper --- xen/arch/x86/efi/efi-boot.h | 38 ++++++++++++++++++++++++++++++-------- xen/arch/x86/setup.c | 3 +-- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h index 2dd69f6..3d25c48 100644 --- a/xen/arch/x86/efi/efi-boot.h +++ b/xen/arch/x86/efi/efi-boot.h @@ -103,9 +103,36 @@ static void __init relocate_trampoline(unsigned long phys) *(u16 *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4; } +#define EBMALLOC_SIZE MB(1) + +static char __initdata ebmalloc_mem[EBMALLOC_SIZE]; +static char __initdata *ebmalloc_free = NULL; + +/* EFI boot allocator. */ +static void __init *ebmalloc(size_t size) +{ + void *ptr; + + /* + * Init ebmalloc_free on runtime. Static initialization + * will not work because it puts virtual address there. + */ + if ( ebmalloc_free == NULL ) + ebmalloc_free = ebmalloc_mem; + + ptr = ebmalloc_free; + + ebmalloc_free += size; + + if ( ebmalloc_free - ebmalloc_mem > sizeof(ebmalloc_mem) ) + blexit(L"Out of static memory\r\n"); + + return ptr; +} + static void __init place_string(u32 *addr, const char *s) { - static char *__initdata alloc = start; + char *alloc = NULL; if ( s && *s ) { @@ -113,7 +140,7 @@ static void __init place_string(u32 *addr, const char *s) const char *old = (char *)(long)*addr; size_t len2 = *addr ? strlen(old) + 1 : 0; - alloc -= len1 + len2; + alloc = ebmalloc(len1 + len2); /* * Insert new string before already existing one. This is needed * for options passed on the command line to override options from @@ -196,12 +223,7 @@ static void __init efi_arch_process_memory_map(EFI_SYSTEM_TABLE *SystemTable, static void *__init efi_arch_allocate_mmap_buffer(UINTN map_size) { - place_string(&mbi.mem_upper, NULL); - mbi.mem_upper -= map_size; - mbi.mem_upper &= -__alignof__(EFI_MEMORY_DESCRIPTOR); - if ( mbi.mem_upper < xen_phys_start ) - return NULL; - return (void *)(long)mbi.mem_upper; + return ebmalloc(map_size); } static void __init efi_arch_pre_exit_boot(void) diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index bce708c..a59fc4e 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -994,8 +994,7 @@ void __init noreturn __start_xen(unsigned long mbi_p) if ( !xen_phys_start ) panic("Not enough memory to relocate Xen."); - reserve_e820_ram(&boot_e820, efi_enabled(EFI_PLATFORM) ? mbi->mem_upper : __pa(&_start), - __pa(&_end)); + reserve_e820_ram(&boot_e820, __pa(&_start), __pa(&_end)); /* Late kexec reservation (dynamic start address). */ kexec_reserve_area(&boot_e820); -- 1.7.10.4