Re: [PATCH 0/4] Process some MMIO-related errors without KVM exit

On Mon, Sep 23, 2024, Ivan Orlov wrote:

Currently, KVM may return a variety of internal errors to VMM when accessing MMIO, and some of them could be gracefully handled on the KVM level instead. Moreover, some of the MMIO-related errors are handled differently in VMX in comparison with SVM, which produces certain inconsistency and should be fixed. This patch series introduces KVM-level handling for the following situations:

1. Guest is accessing MMIO during event delivery: triple fault instead

of internal error on VMX and infinite loop on SVM

2. Guest fetches an instruction from MMIO: inject #UD and resume guest

execution without internal error

No. This is not architectural behavior. It's not even remotely close to architectural behavior. KVM's behavior isn't great, but making up _guest visible_ behavior is not going to happen.