GSI Allocator: free GSIs when they are no longer used#74
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amphi wants to merge 2 commits intocyberus-technology:gardenlinuxfrom
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GSI Allocator: free GSIs when they are no longer used#74amphi wants to merge 2 commits intocyberus-technology:gardenlinuxfrom
amphi wants to merge 2 commits intocyberus-technology:gardenlinuxfrom
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I think a bitmap is trivial enough to keep the functionality in the module itself |
phip1611
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Feb 2, 2026
phip1611
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Feb 2, 2026
| self.gsis.lock().unwrap().alloc() | ||
| } | ||
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| /// Frees a GSI |
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nit/idea: we could also totally over-engineer this:
Each Gsi could be a smart object with a Weak reference to the allcoator. Once the element drops, it removes itself from the GsiAllocator`
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Yes, we could do that. But I am unsure whether we should do that.
Sounds totally over engineered, but on the other hand this would solve the question when to free the interrupts.
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The old implementation used a u32 to allocate new GSIs. The counter increased every time a new GSI was allocated, and freeing GSIs was not possible. Thus, Cloud Hypervisor could run out of GSIs and panic. This new implementation can also free GSIs. Please note that this commit only replaces the old mechanism, the next commit will introduce a mechanism to free used GSIs. While I was here I also propagated the errors that the allocator may throw where necessary. On-behalf-of: SAP sebastian.eydam@sap.com Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
These changes free GSIs when they are no longer used. That way we shouldn't exhaust the available GSIs anymore when attaching and detaching devices. On-behalf-of: SAP sebastian.eydam@sap.com Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
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This PR changes the
GsiAllocatorto enable it to free GSIs when they are no longer used. To do that, it replaces theu32that was used to track used GSIs with a simple bitmap. If you know a good bitmap crate that I should use, please tell me.While I was here, I also made sure that errors from the allocator a propagated. I also used the bitmap for the IRQs of the
GsiAllocator, just because it made it easier for me to propagate useful errors.I am not completely sure whether I free the GSIs at all necessary places.