From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Subject: [PATCH v2 7/7] mm: secretmem: add ability to reserve memory at boot Date: Mon, 27 Jul 2020 19:29:35 +0300 Message-ID: <20200727162935.31714-8-rppt@kernel.org> References: <20200727162935.31714-1-rppt@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from mail.kernel.org ([198.145.29.99]:59694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729573AbgG0Qar (ORCPT ); Mon, 27 Jul 2020 12:30:47 -0400 In-Reply-To: <20200727162935.31714-1-rppt@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org Cc: Alexander Viro , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Idan Yaniv , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mike Rapoport , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt From: Mike Rapoport Taking pages out from the direct map and bringing them back may create undesired fragmentation and usage of the smaller pages in the direct mapping of the physical memory. This can be avoided if a significantly large area of the physical memory would be reserved for secretmem purposes at boot time. Add ability to reserve physical memory for secretmem at boot time using "secretmem" kernel parameter and then use that reserved memory as a global pool for secret memory needs. Signed-off-by: Mike Rapoport --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb95fad81c79..6f3c2f28160f 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4548,6 +4548,10 @@ Format: integer between 0 and 10 Default is 0. + secretmem=n[KMG] + [KNL,BOOT] Reserve specified amount of memory to + back mappings of secret memory. + skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate xtime_lock contention on larger systems, and/or RCU lock contention on all systems with CONFIG_MAXSMP set. -- 2.26.2