On 14/11/19 19:32, Sean Christopherson wrote:
>>> + pr_err_once("x86/cpu: VMX disabled, IA32_FEATURE_CONTROL MSR unsupported\n");
>
> My thought for having the print was to alert the user that something is
> royally borked with their system. There's nothing the user can do to fix
> it per se, but it does indicate that either their hardware or the VMM
> hosting their virtual machine is broken. So maybe be more explicit about
> it being a likely hardware/VMM issue?
Yes, good idea.
>>> +update_caps:
>>> + if (!cpu_has(c, X86_FEATURE_VMX))
>>> + return;
>>
>> If this test is just so we can save us the below code, I'd say remove it
>> for the sake of having less code in that function. The test is cheap and
>> not on a fast path so who cares if we clear an alrady cleared bit. But
>> maybe this evolves in the later patches...
>
> I didn't want to print the "VMX disabled by BIOS..." message if VMX isn't
> supported in the first place. Later patches also add more code in this
> flow, but avoiding the print message is the main motiviation.
I agree on this too.
Paolo
>>> +
>>> + if ((tboot && !(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)) ||
>>> + (!tboot && !(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX))) {
>>> + pr_err_once("x86/cpu: VMX disabled by BIOS (TXT %s)\n",
>>> + tboot ? "enabled" : "disabled");
>>> + clear_cpu_cap(c, X86_FEATURE_VMX);
>>> + }
>>> }
>>
>> --
>> Regards/Gruss,
>> Boris.
>>
>> https://people.kernel.org/tglx/notes-about-netiquette
>
