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Shutemov" To: Dave Hansen Cc: Adrian Hunter , Borislav Petkov , Andrew Morton , Vlastimil Babka , Mike Rapoport , Lorenzo Stoakes , Tom Lendacky , Baoquan He , Vivek Goyal , Dave Young , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [PATCH 3/3] /dev/mem: Do not map unaccepted memory Message-ID: <20230907142510.vcj57cvnewqt4m37@box.shutemov.name> References: <20230906073902.4229-1-adrian.hunter@intel.com> <20230906073902.4229-4-adrian.hunter@intel.com> <9ffb7a3b-cf20-617a-e4f1-8a6a8a2c5972@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ffb7a3b-cf20-617a-e4f1-8a6a8a2c5972@intel.com> X-Rspamd-Queue-Id: B7FE914000E X-Rspam-User: X-Stat-Signature: 6m56c7eepg1tkozos86d6y7dbj1t77j9 X-Rspamd-Server: rspam03 X-HE-Tag: 1694096739-410455 X-HE-Meta: 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 0Bc+8h4B Rdu04IhVGP7gTVWPW3qgXeGIHBXX5gVkkrDjF755g5dVc5/LZ5W3PEJ3A09PwFvyXkXZ47FUSBc7cDaS+RT/uGzgotcdZpv5CbUmTIy0Fd/xoYNY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Sep 07, 2023 at 07:15:21AM -0700, Dave Hansen wrote: > On 9/6/23 00:39, Adrian Hunter wrote: > > Support for unaccepted memory was added recently, refer commit > > dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby > > a virtual machine may need to accept memory before it can be used. > > > > Do not map unaccepted memory because it can cause the guest to fail. > > Doesn't /dev/mem already provide a billion ways for someone to shoot > themselves in the foot? TDX seems to have added the 1,000,000,001st. > Is this really worth patching? Is it better to let TD die silently? I don't think so. -- Kiryl Shutsemau / Kirill A. Shutemov