korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-22 18:44:44 +08:00
Code Issues Packages Projects Releases Wiki Activity

KVM: VMX: Refuse to load kvm_intel if EPT and NX are disabled

Browse Source 
Refuse to load KVM if NX support is not available and EPT is not enabled.
Shadow paging has assumed NX support since commit 9167ab7993 ("KVM:
vmx, svm: always run with EFER.NXE=1 when shadow paging is active"), so
for all intents and purposes this has been a de facto requirement for
over a year.

Do not require NX support if EPT is enabled purely because Intel CPUs let
firmware disable NX support via MSR_IA32_MISC_ENABLES.  If not for that,
VMX (and KVM as a whole) could require NX support with minimal risk to
breaking userspace.

Fixes: 9167ab7993 ("KVM: vmx, svm: always run with EFER.NXE=1 when shadow paging is active")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20210615164535.2146172-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-06-15 09:45:32 -07:00 committed by Paolo Bonzini
parent f1b8325508
commit 23f079c249
1 changed files with 6 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/kvm/vmx/vmx.c
View File

@ -7723,6 +7723,12 @@ static __init int hardware_setup(void)
!cpu_has_vmx_invept_global())
enable_ept = 0;
/* NX support is required for shadow paging. */
if (!enable_ept && !boot_cpu_has(X86_FEATURE_NX)) {
pr_err_ratelimited("kvm: NX (Execute Disable) not supported\n");
return -EOPNOTSUPP;
}
if (!cpu_has_vmx_ept_ad_bits() || !enable_ept)
enable_ept_ad_bits = 0;