From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- .../process/contribution-maturity-model.rst | 109 +++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 Documentation/process/contribution-maturity-model.rst (limited to 'Documentation/process/contribution-maturity-model.rst') diff --git a/Documentation/process/contribution-maturity-model.rst b/Documentation/process/contribution-maturity-model.rst new file mode 100644 index 000000000..b87ab34de --- /dev/null +++ b/Documentation/process/contribution-maturity-model.rst @@ -0,0 +1,109 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================== +Linux Kernel Contribution Maturity Model +======================================== + + +Background +========== + +As a part of the 2021 Linux Kernel Maintainers’ Summit, there was a +`discussion `_ about the challenges in +recruiting kernel maintainers as well as maintainer succession. Some of +the conclusions from that discussion included that companies which are a +part of the Linux Kernel community need to allow engineers to be +maintainers as part of their job, so they can grow into becoming +respected leaders and eventually, kernel maintainers. To support a +strong talent pipeline, developers should be allowed and encouraged to +take on upstream contributions such as reviewing other people’s patches, +refactoring kernel infrastructure, and writing documentation. + +To that end, the Linux Foundation Technical Advisory Board (TAB) +proposes this Linux Kernel Contribution Maturity Model. These common +expectations for upstream community engagement aim to increase the +influence of individual developers, increase the collaboration of +organizations, and improve the overall health of the Linux Kernel +ecosystem. + +The TAB urges organizations to continuously evaluate their Open Source +maturity model and commit to improvements to align with this model. To +be effective, this evaluation should incorporate feedback from across +the organization, including management and developers at all seniority +levels. In the spirit of Open Source, we encourage organizations to +publish their evaluations and plans to improve their engagement with the +upstream community. + +Level 0 +======= + +* Software Engineers are not allowed to contribute patches to the Linux + kernel. + + +Level 1 +======= + +* Software Engineers are allowed to contribute patches to the Linux + kernel, either as part of their job responsibilities or on their own + time. + +Level 2 +======= + +* Software Engineers are expected to contribute to the Linux Kernel as + part of their job responsibilities. +* Software Engineers will be supported to attend Linux-related + conferences as a part of their job. +* A Software Engineer’s upstream code contributions will be considered + in promotion and performance reviews. + +Level 3 +======= + +* Software Engineers are expected to review patches (including patches + authored by engineers from other companies) as part of their job + responsibilities +* Contributing presentations or papers to Linux-related or academic + conferences (such those organized by the Linux Foundation, Usenix, + ACM, etc.), are considered part of an engineer’s work. +* A Software Engineer’s community contributions will be considered in + promotion and performance reviews. +* Organizations will regularly report metrics of their open source + contributions and track these metrics over time. These metrics may be + published only internally within the organization, or at the + organization’s discretion, some or all may be published externally. + Metrics that are strongly suggested include: + + * The number of upstream kernel contributions by team or organization + (e.g., all people reporting up to a manager, director, or VP). + * The percentage of kernel developers who have made upstream + contributions relative to the total kernel developers in the + organization. + * The time interval between kernels used in the organization’s servers + and/or products, and the publication date of the upstream kernel + upon which the internal kernel is based. + * The number of out-of-tree commits present in internal kernels. + +Level 4 +======= + +* Software Engineers are encouraged to spend a portion of their work + time focused on Upstream Work, which is defined as reviewing patches, + serving on program committees, improving core project infrastructure + such as writing or maintaining tests, upstream tech debt reduction, + writing documentation, etc. +* Software Engineers are supported in helping to organize Linux-related + conferences. +* Organizations will consider community member feedback in official + performance reviews. + +Level 5 +======= + +* Upstream kernel development is considered a formal job position, with + at least a third of the engineer’s time spent doing Upstream Work. +* Organizations will actively seek out community member feedback as a + factor in official performance reviews. +* Organizations will regularly report internally on the ratio of + Upstream Work to work focused on directly pursuing business goals. -- cgit v1.3.1