From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1jCje8-000190-8X for mharc-grub-devel@gnu.org; Fri, 13 Mar 2020 08:42:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46491) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jCje5-00017o-Er for grub-devel@gnu.org; Fri, 13 Mar 2020 08:42:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jCje1-0004Vf-73 for grub-devel@gnu.org; Fri, 13 Mar 2020 08:42:32 -0400 Received: from dibed.net-space.pl ([84.10.22.86]:34874) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_3DES_EDE_CBC_SHA1:24) (Exim 4.71) (envelope-from ) id 1jCje0-0004Qw-SU for grub-devel@gnu.org; Fri, 13 Mar 2020 08:42:29 -0400 Received: from router-fw.i.net-space.pl ([192.168.52.1]:46096 "EHLO tomti.i.net-space.pl") by router-fw-old.i.net-space.pl with ESMTP id S1942496AbgCMMmT (ORCPT ); Fri, 13 Mar 2020 13:42:19 +0100 X-Comment: RFC 2476 MSA function at dibed.net-space.pl logged sender identity as: dkiper Date: Fri, 13 Mar 2020 13:42:17 +0100 From: Daniel Kiper To: Patrick Steinhardt Cc: grub-devel@gnu.org, Leif Lindholm , agraf@csgraf.de, pjones@redhat.com, mjg59@google.com, phcoder@gmail.com, Milan Broz Subject: Re: [PATCH v3 1/5] efi: Always try to allocate heap size of 1.6GB Message-ID: <20200313124217.wzmyolxu7az2xtbu@tomti.i.net-space.pl> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 84.10.22.86 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Mar 2020 12:42:34 -0000 On Tue, Mar 10, 2020 at 07:58:28PM +0100, Patrick Steinhardt wrote: > By default, GRUB will allocate a quarter of the pages it got available > in the EFI subsystem. On many current systems, this will amount to > roughly 800MB of RAM assuming an address space of 32 bits. This is > plenty for most use cases, but it doesn't suffice when using full disk > encryption with a key derival function based on Argon2. > > Besides the usual iteration count known from PBKDF2, Argon2 introduces > two additional parameters "memory" and "parallelism". While the latter > doesn't really matter to us, the memory parameter is quite interesting. > If encrypting a partition with LUKS2 using Argon2 as KDF, then > cryptsetup will default to a memory parameter of 1GB. Meaning we need to > allocate a buffer of 1GB in size in order to be able to derive the key, > which definitely won't squeeze into the limit of 800MB. > > To prepare for Argon2, this commit reworks the memory allocation > algorithm for EFI platforms. Instead of trying to allocate a quarter of > memory available, let's instead introduce a constant target amount of > bytes that we try to allocate. The target is set to the previous value > of MAX_HEAP_SIZE, which amounts to 1.6GB and thus sufficiently high to > accomodate for both Argon2 as well as other functionality. The value is > then clamped to at most half of available memory but at least 100MB. It seems to me that 0x100000 (MIN_HEAP_PAGES) equals to 1 MiB... > Signed-off-by: Patrick Steinhardt > --- > grub-core/kern/efi/mm.c | 21 +++++++++++---------- > 1 file changed, 11 insertions(+), 10 deletions(-) > > diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c > index b02fab1b1..367a726c6 100644 > --- a/grub-core/kern/efi/mm.c > +++ b/grub-core/kern/efi/mm.c > @@ -39,8 +39,8 @@ > #define MEMORY_MAP_SIZE 0x3000 > > /* The minimum and maximum heap size for GRUB itself. */ > -#define MIN_HEAP_SIZE 0x100000 > -#define MAX_HEAP_SIZE (1600 * 0x100000) > +#define MIN_HEAP_PAGES BYTES_TO_PAGES( 0x100000) > +#define TARGET_HEAP_PAGES BYTES_TO_PAGES(1600 * 0x100000) > > static void *finish_mmap_buf = 0; > static grub_efi_uintn_t finish_mmap_size = 0; > @@ -559,7 +559,7 @@ grub_efi_mm_init (void) > grub_efi_uintn_t map_size; > grub_efi_uintn_t desc_size; > grub_efi_uint64_t total_pages; > - grub_efi_uint64_t required_pages; > + grub_efi_uint64_t target_heap_pages; > int mm_status; > > /* Prepare a memory region to store two memory maps. */ > @@ -599,14 +599,15 @@ grub_efi_mm_init (void) > filtered_memory_map_end = filter_memory_map (memory_map, filtered_memory_map, > desc_size, memory_map_end); > > - /* By default, request a quarter of the available memory. */ > + /* By default, request TARGET_HEAP_PAGES pages. If that exceeds half of meory > + * available, clamp it, but request at least MIN_HEAP_PAGES. */ > total_pages = get_total_pages (filtered_memory_map, desc_size, > filtered_memory_map_end); > - required_pages = (total_pages >> 2); > - if (required_pages < BYTES_TO_PAGES (MIN_HEAP_SIZE)) > - required_pages = BYTES_TO_PAGES (MIN_HEAP_SIZE); > - else if (required_pages > BYTES_TO_PAGES (MAX_HEAP_SIZE)) > - required_pages = BYTES_TO_PAGES (MAX_HEAP_SIZE); > + target_heap_pages = TARGET_HEAP_PAGES; > + if (target_heap_pages > (total_pages / 2)) > + target_heap_pages = total_pages / 2; > + if (target_heap_pages < MIN_HEAP_PAGES) > + target_heap_pages = MIN_HEAP_PAGES; target_heap_pages = grub_min (total_pages / 2, TARGET_HEAP_PAGES); target_heap_pages = grub_max (target_heap_pages, MIN_HEAP_PAGES); Except that algorithm LGTM. Leif? Daniel