mana vf: poll for shmem ownership before use #966
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…mory - The 256-bit shared memory has an ownership mechanism in the high bit. If high bit is 1, the PF owns the region, and writes by the VF are ignored. If it is 0, the VF owns the region and may write. VF drivers should ensure this bit is 0 before attempting a shared memory write.
jstarks
reviewed
Mar 5, 2025
| let mut ctx = | ||
| mesh::CancelContext::new().with_timeout(Duration::from_millis(HWC_POLL_TIMEOUT_IN_MS)); | ||
| let mut hw_failure = false; | ||
| loop { |
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This is copy/paste. Can we make it a function?
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Yes, and will do. Each is slightly different as it was copied from the wait in each respective function where the response is waited on (one for establish hwc, one for destroy hwc, slightly different from each other though probably not for good reason). To be complete with making a function, we may want all four waits (establish/destroy before sending request, establish/destroy when waiting for response) to be commonized into a single function.
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The 256-bit mmio aperture for bootstrap VF-PF communication has an
ownership mechanism in the high bit. If high bit is 1, the PF owns the
region, and writes by the VF are ignored. If it is 0, the VF owns the
region and may write. VF drivers should ensure this bit is 0 before
attempting a shared memory write.