On 08/02/2018 23:58, Tom Lendacky wrote:
> Provide a new KVM capability that allows bits within MSRs to be recognized
> as features. Two new ioctls are added to the VM ioctl routine to retrieve
> the list of these MSRs and their values. The MSR features can optionally
> be exposed based on a CPU and/or a CPU feature.
Yes, pretty much. Just two changes:
> +struct kvm_msr_based_features {
> + u32 msr; /* MSR to query */
> + u64 mask; /* MSR mask */
> + const struct x86_cpu_id *match; /* Match criteria */
> + u64 value; /* MSR value */
1) These two should be replaced by a kvm_x86_ops callback, because
computing the value is sometimes a bit more complicated than just rdmsr
(for example, MSRs for VMX capabilities depend on the kvm_intel.ko
module parameters).
> + case KVM_CAP_GET_MSR_FEATURES:
This should be KVM_GET_MSR.
> + r = msr_io(NULL, argp, do_get_msr_features, 1);
> + break;
Bonus points for writing documentation :) and for moving the MSR
handling code to arch/x86/kvm/msr.{c,h}.
Thanks,
Paolo
