On 22/10/20 18:35, Jim Mattson wrote: > On Thu, Oct 22, 2020 at 6:02 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >> >> On 22/10/20 03:34, Wanpeng Li wrote: >>> From: Wanpeng Li <wanpengli@xxxxxxxxxxx> >>> >>> Per KVM_GET_SUPPORTED_CPUID ioctl documentation: >>> >>> This ioctl returns x86 cpuid features which are supported by both the >>> hardware and kvm in its default configuration. >>> >>> A well-behaved userspace should not set the bit if it is not supported. >>> >>> Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx> >>> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx> >> >> It's common for userspace to copy all supported CPUID bits to >> KVM_SET_CPUID2, I don't think this is the right behavior for >> KVM_HINTS_REALTIME. > > That is not how the API is defined, but I'm sure you know that. :-) Yes, though in my defense :) KVM_HINTS_REALTIME is not a property of the kernel, it's a property of the environment that the guest runs in. This was the original reason to separate it from other feature bits in the same leaf. Paolo
