From 417b110b9c520b17625f1d9021b108bbf1bcff77 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 24 Jun 2021 17:18:53 -0700 Subject: [PATCH] Revert "KVM: x86: WARN and reject loading KVM if NX is supported but not enabled" Let KVM load if EFER.NX=0 even if NX is supported, the analysis and testing (or lack thereof) for the non-PAE host case was garbage. If the kernel won't be using PAE paging, .Ldefault_entry in head_32.S skips over the entire EFER sequence. Hopefully that can be changed in the future to allow KVM to require EFER.NX, but the motivation behind KVM's requirement isn't yet merged. Reverting and revisiting the mess at a later date is by far the safest approach. This reverts commit 997e04457119aa79b33f35904ba7b189d562683e. Fixes: 997e04457119 ("KVM: x86: WARN and reject loading KVM if NX is supported but not enabled") Signed-off-by: Sean Christopherson Message-Id: <20210625001853.318148-1-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 17468d983fbd5..cf10d196ca65e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10981,9 +10981,6 @@ int kvm_arch_hardware_setup(void *opaque) 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); -- 2.39.5