refactor: de-duplicate virtio queue validation logic #5276
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Just call initialize() again. It does some needless alignment checking, but that's not really harmful. Signed-off-by: Patrick Roy <roypat@amazon.co.uk>
Factor out the alignment checks on the vring components into get_slice_ptr, instead of writing them out 3 times in initialize(). While we're at it, also explain why its okay to only alignment check the GPA and not the HVAs as well. Signed-off-by: Patrick Roy <roypat@amazon.co.uk>
Vring validation was a bit awkwardly split across two functions which did overlapping sets of checks: Queue::initialize verified alignment and memory accesses, while Queue::is_valid additionally checked Queue::ready and Queue::size. However, on the activation path, both were called, meanign we checked alignment twice (.initialize() is called in .activate(), but we only call .activate() if .is_valid() returned true). This is confusing at best, and at worst made us potentially virtio spec incompliant: If the quest tried to activate a virtio device, but this failed because some vring was not valid (in terms of Queue::is_valid), then Firecracker would silently ignore the activation request. Now, it instead marks the device as needing reset, and notifies the guest of its failure to properly configure the vrings. While we're at it, also remove some duplicated checks from the vring restoration code: .initialize() is called for activated devices, so there's no need to later validate the size specifically again, and also no need for the additional call to is_valid(). Signed-off-by: Patrick Roy <roypat@amazon.co.uk>
verify_size only had assertions about our mocks, which is not very useful (in fact, the second assertion was trivially true, no matter what we did). So let's just remove it. Signed-off-by: Patrick Roy <roypat@amazon.co.uk>
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As part of #5260 we noticed that parts of our virtio queue validation logic was duplicated between
Queue::is_validandQueue::initialize, resulting in most queue invariants being checked twice needlessly. This PR fixed this by merging the two functions, and having all validation happen right before activation (refusing to activate the device if validation of any of its queues fails).License Acceptance
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CONTRIBUTING.md.PR Checklist
tools/devtool checkstyleto verify that the PR passes theautomated style checks.
how they are solving the problem in a clear and encompassing way.
in the PR.
CHANGELOG.md.Runbook for Firecracker API changes.
integration tests.
TODO.rust-vmm.