KVM: nSVM: Check that VM_HSAVE_PA MSR was set before VMRUN

APM states that "The address written to the VM_HSAVE_PA MSR, which holds
the address of the page used to save the host state on a VMRUN, must point
to a hypervisor-owned page. If this check fails, the WRMSR will fail with
a #GP(0) exception. Note that a value of 0 is not considered valid for the
VM_HSAVE_PA MSR and a VMRUN that is attempted while the HSAVE_PA is 0 will
fail with a #GP(0) exception."

svm_set_msr() already checks that the supplied address is valid, so only
check for '0' is missing. Add it to nested_svm_vmrun().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210628104425.391276-3-vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 2884c54..ec16a06 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -622,6 +622,11 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
        struct kvm_host_map map;
        u64 vmcb12_gpa;
 
+       if (!svm->nested.hsave_msr) {
+               kvm_inject_gp(vcpu, 0);
+               return 1;
+       }
+
        if (is_smm(vcpu)) {
                kvm_queue_exception(vcpu, UD_VECTOR);
                return 1;