nestedsvm: Clear GIF when injecting VMEXIT

If L1 executes VMRUN with the GIF set and it fails consistency checks,
Xen will inject a VMEXIT and fail the assert checking the GIF is cleared.

Instead, clear the GIF when injecting a VMEXIT to match what hardware
does.

Fixes: 9a779e4fc1 ("Implement SVM specific part for Nested Virtualization")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/hvm/svm/nestedsvm.c

@@ -717,9 +717,9 @@ nsvm_vcpu_vmexit_inject(struct vcpu *v, struct cpu_user_regs *regs,
     struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
 
     if ( vmcb->_vintr.fields.vgif_enable )
-        ASSERT(vmcb->_vintr.fields.vgif == 0);
+        vmcb->_vintr.fields.vgif = 0;
     else
-        ASSERT(svm->ns_gif == 0);
+        svm->ns_gif = 0;
 
     ns_vmcb = nv->nv_vvmcx;