On 11/16/20 12:09 PM, Paolo Bonzini wrote:
On 16/11/20 18:02, Tom Lendacky wrote:
From: Tom Lendacky<thomas.lendacky@amd.com>
Currently, the nested state format is hardcoded to VMX. This will result
in kvm_put_nested_state() returning an error because the KVM SVM support
checks for the nested state to be KVM_STATE_NESTED_FORMAT_SVM. As a
result, kvm_arch_put_registers() errors out early.
Update the setting of the format based on the virtualization feature:
VMX - KVM_STATE_NESTED_FORMAT_VMX
SVM - KVM_STATE_NESTED_FORMAT_SVM
Looks good, but what are the symptoms of this in practice?
I discovered this while testing my SEV-ES patches. When I specified the
'+svm' feature, the new SEV-ES reset address for the APs wasn't getting
set because kvm_arch_put_registers() erred out before it could call
kvm_getput_regs(). This resulted in the guest crashing when OVMF tried to
start the APs.
For a non-SEV-ES guest, I'm not sure if other updates could be missed,
potentially.