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X-CSE-ConnectionGUID: pYwrbHTfRuuwHG8+12MRRQ== X-CSE-MsgGUID: 1sbcc46BR2iPqRcOjD0ixA== X-IronPort-AV: E=McAfee;i="6700,10204,11421"; a="35518292" X-IronPort-AV: E=Sophos;i="6.15,257,1739865600"; d="scan'208";a="35518292" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 May 2025 11:39:33 -0700 X-CSE-ConnectionGUID: q0hFwjtbQLOO4bDICzglEA== X-CSE-MsgGUID: j7CeDysPRziSOaNh1q4L1w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,257,1739865600"; d="scan'208";a="134663550" Received: from bjrankin-mobl3.amr.corp.intel.com (HELO [10.124.220.153]) ([10.124.220.153]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 May 2025 11:39:32 -0700 Message-ID: <425b4cbc-d36c-42b6-9071-3e0afab91441@intel.com> Date: Fri, 2 May 2025 11:39:29 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 13/18] x86/e820: temporarily enable KHO scratch for memory below 1M To: Changyuan Lyu , linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, corbet@lwn.net, dave.hansen@linux.intel.com, devicetree@vger.kernel.org, dwmw2@infradead.org, ebiederm@xmission.com, graf@amazon.com, hpa@zytor.com, jgowans@amazon.com, kexec@lists.infradead.org, krzk@kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, mark.rutland@arm.com, mingo@redhat.com, pasha.tatashin@soleen.com, pbonzini@redhat.com, peterz@infradead.org, ptyadav@amazon.de, robh@kernel.org, rostedt@goodmis.org, rppt@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, tglx@linutronix.de, thomas.lendacky@amd.com, will@kernel.org, x86@kernel.org References: <20250501225425.635167-1-changyuanl@google.com> <20250501225425.635167-14-changyuanl@google.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/1/25 15:54, Changyuan Lyu wrote: > From: Alexander Graf > > KHO kernels are special and use only scratch memory for memblock > allocations, but memory below 1M is ignored by kernel after early boot > and cannot be naturally marked as scratch. > > To allow allocation of the real-mode trampoline and a few (if any) other > very early allocations from below 1M forcibly mark the memory below 1M > as scratch. > > After real mode trampoline is allocated, clear that scratch marking. It's much more clear now, thanks! Acked-by: Dave Hansen