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Peter Anvin" To: Andrew Cooper , dave.hansen@intel.com CC: acme@redhat.com, aik@amd.com, akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, ardb@kernel.org, ast@kernel.org, bp@alien8.de, brijesh.singh@amd.com, changbin.du@huawei.com, christophe.leroy@csgroup.eu, corbet@lwn.net, daniel.sneddon@linux.intel.com, dave.hansen@linux.intel.com, ebiggers@google.com, geert+renesas@glider.be, houtao1@huawei.com, jgg@ziepe.ca, jgross@suse.com, jpoimboe@kernel.org, kai.huang@intel.com, kees@kernel.org, kirill.shutemov@linux.intel.com, leitao@debian.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux@rasmusvillemoes.dk, luto@kernel.org, mcgrof@kernel.org, mhiramat@kernel.org, michael.roth@amd.com, mingo@kernel.org, mingo@redhat.com, namhyung@kernel.org, paulmck@kernel.org, pawan.kumar.gupta@linux.intel.com, peterz@infradead.org, rick.p.edgecombe@intel.com, rppt@kernel.org, sandipan.das@amd.com, shijie@os.amperecomputing.com, sohil.mehta@intel.com, tglx@linutronix.de, tj@kernel.org, tony.luck@intel.com, vegard.nossum@oracle.com, x86@kernel.org, xin3.li@intel.com, xiongwei.song@windriver.com, ytcoode@gmail.com Subject: =?US-ASCII?Q?Re=3A_=5BPATCHv6_00/16=5D_x86=3A_Enable_Lin?= =?US-ASCII?Q?ear_Address_Space_Separation_support?= User-Agent: K-9 Mail for Android In-Reply-To: <1aa5fb31-ce23-4c9f-ba1b-d5dc93402209@citrix.com> References: <61af62d9-4cd0-485f-8f0c-2da981f52695@intel.com> <1aa5fb31-ce23-4c9f-ba1b-d5dc93402209@citrix.com> Message-ID: <97B65822-F133-4F7C-AFCD-6E3BB1EDCF9F@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam03 X-Stat-Signature: pt6rro7ymbd4hk416uhgdw6q3nbnm46p X-Rspam-User: X-Rspamd-Queue-Id: 6AB1640008 X-HE-Tag: 1750458646-828084 X-HE-Meta: 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 dCXd1Liz fs7xkNMBjEnOc+YO1VAWXeSmiJwTTx68oVtFPXNHxEaK6UlaMDJSlH993hATTWvKhzfpxzSJcFKc811BZE7YEiEl64UNHvX/Mqw6fOzM/GTkUWF1QN4GQ2/0skjy5JE6O59F4fyzLhSY/I+R1IEN2X6eOfxXwiXnegcAsqpgGHIwatOQ1nwCon/SEf5ozcSRoxXlwQDrfRBe92pMjgSfwqDpMI9hyJgq2JQMHTN5l4bgTZMg/y/3vrEsZP1Bi0T1miBSbntHT3QS1stVyhrBsZqDO2m58/880OGSrBoCJcXBzSL3/u2BmO4i02vb/CxQXlaE8SU+kHNNvPnbmys3km1J8MYMU+Or2R61l7zMzTUCIKJe0VqDZO/P//XH5rm+S+nVLjiFlHbIuOejId06kW3wBG61MkxtYv3as6acSCbeJ0QpsAScojqXQxQVVq0wf0KNT 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: List-Subscribe: List-Unsubscribe: On June 20, 2025 3:04:53 PM PDT, Andrew Cooper wrote: >> Most of the cover letter here reads like an Intel whitepaper=2E That's = not >> the worst thing in the world, but I think it glosses over one very >> important point: >> >> Had it been available, LASS alone would have mitigated Meltdown=2E >> >> Could we say this up front in a prominent place, please? > >I'm going to nitpick=2E :) > >Yes, LASS would have made Meltdown a far less major problem than it was, >but I don't think that phrasing is fair=2E=C2=A0 As I recall, LASS was >literally invented as a "what would have been useful?" exercise in the >wake of Meltdown=2E > >However, a less well known/researched area of Meltdown, which would not >be addressed by LASS, is the ability to pend stores to read-only memory >and proceed with the expectation that they'll success=2E > >Other things which would have helped would have been PKS (and this *was* >asked for ahead of Skylake launching=2E=2E=2E) > >The other important thing about LASS is that it does cut off a whole >class of sidechannels=2E=C2=A0 This halts definitely-rogue speculation, b= ut is >useful for non-speculative security too=2E > >~Andrew Could you clarify what you mean with "pend stores to read-only memory?"