KVM: x86: emulator: update the emulation mode after rsm

Update the emulation mode after RSM so that RIP will be correctly
written back, because the RSM instruction can switch the CPU mode from
32 bit (or less) to 64 bit.

This fixes a guest crash in case the #SMI is received while the guest
runs a code from an address > 32 bit.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221025124741.228045-13-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -2662,7 +2662,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	 * those side effects need to be explicitly handled for both success
 	 * and shutdown.
 	 */
-	return X86EMUL_CONTINUE;
+	return emulator_recalc_and_set_mode(ctxt);
 
 emulate_shutdown:
 	ctxt->ops->triple_fault(ctxt);