On Mon, Feb 10, 2025, Tom Lendacky wrote: > On 2/10/25 03:22, Nikunj A Dadhania wrote: > > Disallow writes to MSR_IA32_TSC for Secure TSC enabled SNP guests, as such > > writes are not expected. Log the error and return #GP to the guest. > > Re-word this to make it a bit clearer about why this is needed. It is > expected that the guest won't write to MSR_IA32_TSC or, if it does, it > will ignore any writes to it and not exit to the HV. So this is catching > the case where that behavior is not occurring. Unless it's architectural impossible for KVM to modify MSR_IA32_TSC, I don't see any reason for KVM to care. If the guest wants to modify TSC, that's the guest's prerogative. If KVM _can't_ honor the write, then that's something else entirely, and the changelog should pretty much write itself.
