WARN if NX is reported as supported but not enabled in EFER. All flavors
of the kernel, including non-PAE 32-bit kernels, set EFER.NX=1 if NX is
supported, even if NX usage is disable via kernel command line. KVM relies
on NX being enabled if it's supported, e.g. KVM will generate illegal NPT
entries if nx_huge_pages is enabled and NX is supported but not enabled.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <
20210615164535.
2146172-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
int r;
rdmsrl_safe(MSR_EFER, &host_efer);
+ if (WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_NX) &&
+ !(host_efer & EFER_NX)))
+ return -EIO;
if (boot_cpu_has(X86_FEATURE_XSAVES))
rdmsrl(MSR_IA32_XSS, host_xss);