4.17-stable review patch. If anyone has any objections, please let me know.
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From: Felix Wilhelm fwilhelm@google.com
commit 727ba748e110b4de50d142edca9d6a9b7e6111d8 upstream.
VMX instructions executed inside a L1 VM will always trigger a VM exit even when executed with cpl 3. This means we must perform the privilege check in software.
Fixes: 70f3aac964ae("kvm: nVMX: Remove superfluous VMX instruction fault checks") Cc: stable@vger.kernel.org Signed-off-by: Felix Wilhelm fwilhelm@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/vmx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7670,6 +7670,12 @@ static int handle_vmon(struct kvm_vcpu * return 1; }
+ /* CPL=0 must be checked manually. */ + if (vmx_get_cpl(vcpu)) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + if (vmx->nested.vmxon) { nested_vmx_failValid(vcpu, VMXERR_VMXON_IN_VMX_ROOT_OPERATION); return kvm_skip_emulated_instruction(vcpu); @@ -7729,6 +7735,11 @@ static int handle_vmon(struct kvm_vcpu * */ static int nested_vmx_check_permission(struct kvm_vcpu *vcpu) { + if (vmx_get_cpl(vcpu)) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 0; + } + if (!to_vmx(vcpu)->nested.vmxon) { kvm_queue_exception(vcpu, UD_VECTOR); return 0; @@ -8029,7 +8040,7 @@ static int handle_vmread(struct kvm_vcpu if (get_vmx_mem_address(vcpu, exit_qualification, vmx_instruction_info, true, &gva)) return 1; - /* _system ok, as hardware has verified cpl=0 */ + /* _system ok, nested_vmx_check_permission has verified cpl=0 */ kvm_write_guest_virt_system(&vcpu->arch.emulate_ctxt, gva, &field_value, (is_long_mode(vcpu) ? 8 : 4), NULL); } @@ -8189,7 +8200,7 @@ static int handle_vmptrst(struct kvm_vcp if (get_vmx_mem_address(vcpu, exit_qualification, vmx_instruction_info, true, &vmcs_gva)) return 1; - /* ok to use *_system, as hardware has verified cpl=0 */ + /* *_system ok, nested_vmx_check_permission has verified cpl=0 */ if (kvm_write_guest_virt_system(&vcpu->arch.emulate_ctxt, vmcs_gva, (void *)&to_vmx(vcpu)->nested.current_vmptr, sizeof(u64), &e)) {