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Can your VMM and GHCI > > sort it out? > > Kevin and Yilun are analyzing what kind of errors we should expect the VMM to > handle. But some of the cases Zhenzhong listed seem like they could be > situations trusted IO guests could encounter generally. Like the example > "[device] firmware hangs during lock/unlock". In that case unification in TSM > could be nice. > > For errors that indicate uncooperative or buggy host, we elsewhere warn in the > TDX wrappers. But in coco, not handling an error in the caller can be an avenue > to attack the guest. So I guess we would commonly need to handle these errors in > the callers. Any failure to attest should just propogate to guest userspace and userspace wil fail the attestation and not enable the device. This is fine. All failure classes, including the cases where the guest is checking digests/etc to confirm the host has done the right thing can work like this. > Zhenzhong had previously suggested a bool to set a device as bugged for the > purpose of trying to continue guest execution as well as possible in the face of > host issues. It does not seem necessary to me, userspace is responsible. Since no device evidence could possibly have been logged the VM would fail attestation anyhow. Jason