From: Sean Christopherson sean.j.christopherson@intel.com
stable inclusion from stable-v5.10.137 commit 8b8b376903b32d3d854f39eeebe018169c920cb6 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit d3a9e4146a6f79f19430bca3f2a4d6ebaaffe36b ]
Drop vmx_set_cr4()'s somewhat hidden guest_cpuid_has() check on VMXE now that common x86 handles the check by incorporating VMXE into the CR4 reserved bits, i.e. in cr4_guest_rsvd_bits. This fixes a bug where KVM incorrectly rejects KVM_SET_SREGS with CR4.VMXE=1 if it's executed before KVM_SET_CPUID{,2}.
Fixes: 5e1746d6205d ("KVM: nVMX: Allow setting the VMXE bit in CR4") Reported-by: Stas Sergeev stsp@users.sourceforge.net Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com Message-Id: 20201007014417.29276-2-sean.j.christopherson@intel.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- arch/x86/kvm/vmx/vmx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 131f2a1e3e3d..c060e7872b0f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3361,9 +3361,10 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) * must first be able to turn on cr4.VMXE (see handle_vmon()). * So basically the check on whether to allow nested VMX * is here. We operate under the default treatment of SMM, - * so VMX cannot be enabled under SMM. + * so VMX cannot be enabled under SMM. Note, guest CPUID is + * intentionally ignored, it's handled by cr4_guest_rsvd_bits. */ - if (!nested_vmx_allowed(vcpu) || is_smm(vcpu)) + if (!nested || is_smm(vcpu)) return 1; }