cpu/percpu: store safe references to HV doorbell page and SVSM VMSA #387
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00xc
commented
Jun 19, 2024
00xc
commented
- Store a safe reference to the HV doorbell in the PerCpu
- Cleanups and add some documentation
- Store a safe reference to the SVSM VMSA in the PerCpu
Mutable references to the HV doorbell page are never given, as its data is fully atomic. Thus, there is no need to use raw pointers. Since we need a pointer to the location of the safe reference itself in the PerCpu for #HV servicing, use a OnceCell, which gives out references to the inner T under the assumption that the type can only be set once, which suits our use. With a &T (in this case a &&'static HVDoorbell), we can obtain a pointer to the inner value. Signed-off-by: Carlos López <[email protected]>
Document some parts of the PerCpu that might not be straightforward to understand. Signed-off-by: Carlos López <[email protected]>
There is no need for the several steps of SVSM VMSA initialization to be split up, and they only make for a more awkward initialization. Thus, merge them into a single PerCpu method. Signed-off-by: Carlos López <[email protected]>
start_cpu() had several calls to expect() on various error conditions. Clean up the function by returning the error and letting the caller panic with the specific error. Signed-off-by: Carlos López <[email protected]>
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Once this is merged I'll rework #348 to remove the remaining unsafe around page allocations |
msft-jlange
reviewed
Jun 22, 2024
msft-jlange
reviewed
Jun 22, 2024
The SVSM VMSA only needs to me mutated during initialization. Thus simply encapsulate that step in a PerCpu method and store an immutable reference to the VMSA, avoiding the possibility of mutably aliasing it. This obsoletes the VmsaRef type. Signed-off-by: Carlos López <[email protected]>
msft-jlange
approved these changes
Jun 23, 2024
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