virt_mshv_vtl, SNP: Fix a todo in the intercept processing #1628
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| // Ignore. | ||
| // | ||
| // TODO SNP: Figure out why we are getting these. | ||
| HvMessageType::HvMessageTypeX64Halt => { |
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Where is it being processed?
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- Above in the
matchblock, there is an arm for the HLT exit, - In the same block, when processing the MSR exit,
read_msr_snpis called which checks forhvdef::HV_X64_MSR_GUEST_IDLE.
The intercept message from the hypervisor can't offer a better/more trustworthy data than that one (generated by the hardware). Both cases are handled with the VP "parked" in the state allowing for interrupts being delivered. That all made the impression all that's required to be done must be already done.
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Maybe we should assert or check/warn that the SevExitCode is what we'd expect here?
Implement what the TODO requests: * Add a comment to explain why halt messages are expected, * Check that the only exception intercept messages are for the VC traps, and document that. Tested by booting various SEV-SNP VMs.
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Pull Request Overview
This PR addresses a TODO comment in the SNP (SEV-SNP) intercept processing code by implementing proper handling and validation for two specific message types: halt messages and exception intercept messages.
- Separates the handling of halt and exception intercept messages that were previously grouped together
- Adds documentation explaining why halt messages are expected and require no action
- Implements validation for exception intercept messages to ensure only #VC (VMM Communication) traps are received
| .runner | ||
| .exit_message() | ||
| .as_message::<hvdef::HvX64ExceptionInterceptMessage>(); | ||
| if exception_message.vector |
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Consider adding a comment explaining what the SEV_VMM_COMMUNICATION exception vector represents and why it's the only expected exception type in the SNP context.
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Implement what the TODO requests:
Tested by booting various SEV-SNP VMs.