First, the MSR should be added to msrs_to_save_all and
kvm_cpu_cap_has(X86_FEATURE_XFD) should be checked in kvm_init_msr_list.
It seems that RDMSR support is missing, too.
More important, please include:
- documentation for the new KVM_EXIT_* value
- a selftest that explains how userspace should react to it.
This is a strong requirement for any new API (the first has been for
years; but the latter is also almost always respected these days). This
series should not have been submitted without documentation.
Also:
On 12/8/21 01:03, Yang Zhong wrote:
+ if (!guest_cpuid_has(vcpu, X86_FEATURE_XFD))
+ return 1;
This should allow msr->host_initiated always (even if XFD is not part of
CPUID). However, if XFD is nonzero and kvm_check_guest_realloc_fpstate
returns true, then it should return 1.
The selftest should also cover using KVM_GET_MSR/KVM_SET_MSR.
+ /* Setting unsupported bits causes #GP */
+ if (~XFEATURE_MASK_USER_DYNAMIC & data) {
+ kvm_inject_gp(vcpu, 0);
+ break;
+ }
This should check
if (data & ~(XFEATURE_MASK_USER_DYNAMIC &
vcpu->arch.guest_supported_xcr0))
instead.
Paolo
