CVM Guest VSM: refactor the shared/encrypted bitmaps to be partition-wide #1370
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openhcl/underhill_mem/src/mapping.rs
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| impl<'a> GuestPartitionMemoryBuilder<'a> { | ||
| /// valid_bitmap_state is valid when allocating a tracking bitmap is needed |
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nit: usually we markdown format variables, input parameters with . so it would look something like valid_bitmap_state`, since that renders nicer in rustdoc.
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| pub fn partition_valid_memory(&self) -> Option<Arc<GuestValidMemory>> { |
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missing doc comments on these two?
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| pub fn update_valid(&self, range: MemoryRange, state: bool) { | ||
| let _lock = self.valid_bitmap_lock.lock(); |
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why is this lock here when we don't use it at all when checking validity? what's the point?
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the bitmap is already being done with an atomic update with read_at/write_at - so why the lock? don't we already have issues around TOCTOU if one VP reads the bitmap before a update call on another VP completes?
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This lock existed in GuestMemoryMapping already, so this change only moves it around. I think the lock helps guarantee consistency just around the entire update operation, but then John's RCU change should help with synchronizing those writes with reading the bitmaps.
| registrar: Option<MemoryRegistrar<MshvVtlWithPolicy>>, | ||
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| #[derive(Debug)] | ||
| struct GuestMemoryBitmap { |
sluck-msft
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backport_2505
In preparation for VTL 1 memory support for CVMs, make the shared/encrypted bitmap tracking available on a partition-level, rather than in the GuestMemoryMapping (which ends up being per-VTL). Also includes some refactoring to isolate out the bitmap logic so that it can be reused for vtl protection bitmaps.
Tested: SNP +/- guest vsm boots