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X-CSE-ConnectionGUID: Sv5rVXY+RwmZktGkS0MXsw== X-CSE-MsgGUID: J/Zv3nv8RBq0jx7ssaBuAQ== X-IronPort-AV: E=McAfee;i="6800,10657,11475"; a="55775588" X-IronPort-AV: E=Sophos;i="6.16,265,1744095600"; d="scan'208";a="55775588" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2025 09:57:09 -0700 X-CSE-ConnectionGUID: +xHjEmsYS2yLU1TNcdgGzw== X-CSE-MsgGUID: SrWISwehRIGlH1i8YeM6wg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,265,1744095600"; d="scan'208";a="156537623" Received: from dwoodwor-mobl2.amr.corp.intel.com (HELO [10.125.108.244]) ([10.125.108.244]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2025 09:57:08 -0700 Message-ID: <2c8075f0-2817-4895-a509-bcf1a0771bff@intel.com> Date: Wed, 25 Jun 2025 09:57:07 -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 2/2] KVM: TDX: Do not clear poisoned pages To: Adrian Hunter Cc: Tony Luck , pbonzini@redhat.com, seanjc@google.com, Borislav Petkov , Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, H Peter Anvin , linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kirill.shutemov@linux.intel.com, kai.huang@intel.com, reinette.chatre@intel.com, xiaoyao.li@intel.com, tony.lindgren@linux.intel.com, binbin.wu@linux.intel.com, isaku.yamahata@intel.com, yan.y.zhao@intel.com, chao.gao@intel.com, Vishal Annapurve , rick.p.edgecombe@intel.com References: <20250618120806.113884-1-adrian.hunter@intel.com> <20250618120806.113884-3-adrian.hunter@intel.com> <68938275-3f6a-46fc-9b38-2c916fdec3d6@intel.com> <8f05cd1c-74cf-4370-a39c-8e06cdf2c921@intel.com> <6de76911-5007-4170-bf74-e1d045c68465@intel.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 6/25/25 09:42, Adrian Hunter wrote: > On 25/06/2025 19:31, Dave Hansen wrote: >> On 6/25/25 09:25, Adrian Hunter wrote: >>>> IIUC, even if movdir64b stores contents on hwpoisoned pages, it's not >>>> going to cause any trouble. >>> No. PageHWPoison(page) means the page should not be touched. It must >>> be freed back to the allocator where it will never be allocated again. >> >> What's the end-user-visible effect if the page is touched in this >> specific function in this specific way (with movdir64b)? >> >> In other words, what does this patch do for end users? > > We have another patch that clarifies that. It turns out we need > to clear pages (MOVDIR64B) only if the platform has the so-called > partial-write errata X86_BUG_TDX_PW_MCE. > > It was decided to deal with that issue separately, but maybe it > needs to bundled in the same patch set, now that the discussion > has moved in that direction? It sure sounds like it to me.