diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-06-13 13:30:35 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-07-29 11:05:31 -0400 |
| commit | 26a0652cb453c72f6aab0974bc4939e9b14f886b (patch) | |
| tree | f23de4e5d5d068a437166b6e3b7a837505989bd3 /arch/x86/kvm/svm/svm.c | |
| parent | 880218361c10d6dd7f99423d621112b8770fc32f (diff) | |
KVM: x86: Disallow KVM_SET_SREGS{2} if incoming CR0 is invalid
Reject KVM_SET_SREGS{2} with -EINVAL if the incoming CR0 is invalid,
e.g. due to setting bits 63:32, illegal combinations, or to a value that
isn't allowed in VMX (non-)root mode. The VMX checks in particular are
"fun" as failure to disallow Real Mode for an L2 that is configured with
unrestricted guest disabled, when KVM itself has unrestricted guest
enabled, will result in KVM forcing VM86 mode to virtual Real Mode for
L2, but then fail to unwind the related metadata when synthesizing a
nested VM-Exit back to L1 (which has unrestricted guest enabled).
Opportunistically fix a benign typo in the prototype for is_valid_cr4().
Cc: stable@vger.kernel.org
Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000f316b705fdf6e2b4@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230613203037.1968489-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index cea08e5fa69b..956726d867aa 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1786,6 +1786,11 @@ static void sev_post_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) } } +static bool svm_is_valid_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) +{ + return true; +} + void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) { struct vcpu_svm *svm = to_svm(vcpu); @@ -4809,6 +4814,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .set_segment = svm_set_segment, .get_cpl = svm_get_cpl, .get_cs_db_l_bits = svm_get_cs_db_l_bits, + .is_valid_cr0 = svm_is_valid_cr0, .set_cr0 = svm_set_cr0, .post_set_cr3 = sev_post_set_cr3, .is_valid_cr4 = svm_is_valid_cr4, |