Messages in this thread | | | Date | Thu, 7 Apr 2022 09:17:51 +0800 | Subject | Re: [RFC PATCH v5 026/104] KVM: TDX: x86: Add vm ioctl to get TDX systemwide parameters | From | Xiaoyao Li <> |
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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@intel.com 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 >>> >> >
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