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charset="UTF-8" X-Rspam-User: X-Rspamd-Queue-Id: 11371C000A X-Rspamd-Server: rspam01 X-Stat-Signature: cgmhrf1ddfapo8oqtyd8s1mamxfi63bk X-HE-Tag: 1674697399-269335 X-HE-Meta: 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 415Xs3zX 5vZpPt9UfYTq8x1xfZkqlmztJh8BO929Y9bMpjPXHbradf+Y/V/TVTFbwlJiyRU33Mp7GnxzS6rFVTNTgruhQGbPVpk7A8xlcCQ1v+O2GM1BKzye0I+qniES9ss45AGA+OAW5iE4VmbVB8ilMZtACKP62Qnk+9cmPHw73rCrRrU8HPPzvswzt9+UCHQG30pAizzz/UbSKgM+Frw0EsXZ45C47vpBpFcTr7kjkBropEOFrLkyXQVVMQ6b8UOnqaPAuTGLJqav4x2PeNFOZ2MYIIapSnBf75Hmr8BdsXxkr5/qEfJkqhFUvOj6DfeOHVm2h6ycqMRdjPxdgwGMKC3jqvVv5ZWH9dVWwAdk35KV9z3G0Bbw= 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 Wed, Jan 25, 2023 at 11:13 AM Dave Hansen wrote: > > On 1/25/23 11:02, Jeff Xu wrote: > > I'm investigating if there is a need to backport x86/pkeys > > fix/feature into earlier kernel versions, Chrome is starting to use > > PKEY in x86, and I hope experts here can give advice on this. > > > > For background, ChromeOS regularly syncs with upstream kernel > > versions, and has production that uses 4.4/4.14/4.19/5.4/5.10/5.15. > To be honest, I haven't got the foggiest idea what you need to backport. > I can barely keep track of mainline. > > Are there really production 4.4 kernels that you need to run on > pkey-capable hardware? That would mean running a 2015-era kernel on a > CPU released in late 2020. I think Q3'2020 is when the 11th gen CPUs > came out which were the first non-server CPUs that had pkeys. > Thanks! For 11th gen CPUs, chromebook uses 5.4 and above, so that eliminate half of the versions. > On a positive note, the pkeys selftest has been pretty consistently > updated as we find bugs. I'd be curious how well a mainline version of > that selftests runs on old kernels. But, I'm too scared to find out > what's down that particular rabbit hole myself. I can start with 5.10 or 5.15, it seems there are quite some changes though, for example, this one by Thomas https://lore.kernel.org/lkml/20210623120127.327154589@linutronix.de/ My question is, if I have to pick a version that doesn't require a lot of backporting, and functionality is stable enough, what version would this be ? 5.4/5.10/5.15 ? -Jeff