From 2da1ed62d55c6cbebbdee924f6af4e87bb6666e5 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 20 Mar 2020 13:34:50 -0400 Subject: KVM: SVM: document KVM_MEM_ENCRYPT_OP, let userspace detect if SEV is available Userspace has no way to query if SEV has been disabled with the sev module parameter of kvm-amd.ko. Actually it has one, but it is a hack: do ioctl(KVM_MEM_ENCRYPT_OP, NULL) and check if it returns EFAULT. Make it a little nicer by returning zero for SEV enabled and NULL argument, and while at it document the ioctl arguments. Cc: Brijesh Singh Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 91000501756e..f0aa9ff9666f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -7158,6 +7158,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp) if (!svm_sev_enabled()) return -ENOTTY; + if (!argp) + return 0; + if (copy_from_user(&sev_cmd, argp, sizeof(struct kvm_sev_cmd))) return -EFAULT; -- cgit v1.2.3-58-ga151