From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Subject: Re: [PATCH v2 7/7] mm: secretmem: add ability to reserve memory at boot Date: Mon, 27 Jul 2020 20:11:02 +0300 Message-ID: <20200727171102.GA3655207@kernel.org> References: <20200727162935.31714-1-rppt@kernel.org> <20200727162935.31714-8-rppt@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200727162935.31714-8-rppt@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org 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 , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley List-Id: linux-arch.vger.kernel.org Oops, something went wrong with the rebase, this should have been squashed into the previous patch... On Mon, Jul 27, 2020 at 07:29:35PM +0300, Mike Rapoport wrote: > 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 > -- Sincerely yours, Mike. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:45584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728712AbgG0RLR (ORCPT ); Mon, 27 Jul 2020 13:11:17 -0400 Date: Mon, 27 Jul 2020 20:11:02 +0300 From: Mike Rapoport Subject: Re: [PATCH v2 7/7] mm: secretmem: add ability to reserve memory at boot Message-ID: <20200727171102.GA3655207@kernel.org> References: <20200727162935.31714-1-rppt@kernel.org> <20200727162935.31714-8-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200727162935.31714-8-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 , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Thomas Gleixner , Tycho Andersen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org Message-ID: <20200727171102.vkquukG_nrY9WF13Ia7h8uah-kS88fBKInfRzf8PrEg@z> Oops, something went wrong with the rebase, this should have been squashed into the previous patch... On Mon, Jul 27, 2020 at 07:29:35PM +0300, Mike Rapoport wrote: > 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 > -- Sincerely yours, Mike.