Messages in this thread | | | Subject | Re: [RFC PATCH v7 17/23] kernel/entry: Add support for core-wide protection of kernel-mode | From | Vineeth Pillai <> | Date | Thu, 3 Sep 2020 07:05:25 -0400 |
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On 9/3/20 12:34 AM, Joel Fernandes wrote: >> >> Indeed! For at least two reasons, IMO: >> >> 1) what Thomas is saying already. I.e., even on a CPU which has HT but >> is not affected by any of the (known!) speculation issues, one may want >> to use Core Scheduling _as_a_feature_. For instance, for avoiding >> threads from different processes, or vCPUs from different VMs, sharing >> cores (e.g., for better managing their behavior/performance, or for >> improved fairness of billing/accounting). And in this case, this >> mechanism for protecting the kernel from the userspace on the other >> thread may not be necessary or interesting; > Agreed. So then I should really make this configurable and behind a > sysctl then. I'll do that. We already have the patch to wrap this feature in a build time and boot time option: https://lwn.net/ml/linux-kernel/9cd9abad06ad8c3f35228afd07c74c7d9533c412.1598643276.git.jdesfossez@digitalocean.com/
I could not get to a safe way to make it a runtime tunable at the time of posting this series, but I think it should also be possible.
Thanks, Vineeth
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