Re: [PATCH v4] KVM: x86: Fix KVM_GET_CPUID2 ioctl to return cpuid entries count

From: Paolo Bonzini
Date: Tue May 04 2021 - 03:23:14 EST


On 03/05/21 21:18, Denis V. Lunev wrote:
On 5/3/21 5:54 PM, Paolo Bonzini wrote:
On 29/04/21 03:00, Sean Christopherson wrote:
On Wed, Apr 28, 2021, Valeriy Vdovin wrote:
It's very explicit by the code that it was designed to receive some
small number of entries to return E2BIG along with the corrected
number.

LOL, saying KVM_GET_CPUID2 was "designed" is definitely giving the KVM
forefathers the benefit of the doubt.

I was going to make a different joke, i.e. that KVM_GET_CPUID2 was
indeed designed the way Valeriy described, but that design was
forgotten soon after.

Really, this ioctl has been such a trainwreck that I think the only
good solution here is to drop it.

Paolo


should we discuss KVM_GET_CPUID3 which will work "normally"?

Is anybody using KVM_GET_CPUID2 at all?

Paolo