On 4/7/2022 9:07 AM, Kai Huang wrote:
On Wed, 2022-04-06 at 09:54 +0800, Xiaoyao Li wrote:
On 4/5/2022 8:52 PM, Paolo Bonzini wrote:
On 3/4/22 20:48, isaku.yamahata@xxxxxxxxx wrote:
Implement a VM-scoped subcomment to get system-wide parameters. Although
this is system-wide parameters not per-VM, this subcomand is VM-scoped
because
- Device model needs TDX system-wide parameters after creating KVM VM.
- This subcommands requires to initialize TDX module. For lazy
initialization of the TDX module, vm-scope ioctl is better.
Since there was agreement to install the TDX module on load, please
place this ioctl on the /dev/kvm file descriptor.
At least for SEV, there were cases where the system-wide parameters are
needed outside KVM, so it's better to avoid requiring a VM file descriptor.
I don't have strong preference on KVM-scope ioctl or VM-scope.
Initially, we made it KVM-scope and change it to VM-scope in this
version. Yes, it returns the info from TDX module, which doesn't vary
per VM. However, what if we want to return different capabilities
(software controlled capabilities) per VM?
In this case, you don't return different capabilities, instead, you return the
same capabilities but control the capabilities on per-VM basis.
yes, so I'm not arguing it or insisting on per-VM.
I just speak out my concern since it's user ABI.
Part of the TDX capabilities
serves like get_supported_cpuid, making it KVM wide lacks the
flexibility to return differentiated capabilities for different TDs.
Thanks,
Paolo
