LoongArch: KVM: Fix "unreliable stack" for kvm_exc_entry

commit b323a44 upstream.

Insert the appropriate UNWIND hint into the kvm_exc_entry assembly
function to guide the generation of correct ORC table entries, thereby
solving the timeout problem ("unreliable stack") while loading the
livepatch-sample module on a physical machine running virtual machines
with multiple vcpus.

Cc: stable@vger.kernel.org
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: lixianglai

arch/loongarch/kvm/switch.S

@@ -111,7 +111,7 @@
 	.p2align PAGE_SHIFT
 	.cfi_sections	.debug_frame
 SYM_CODE_START(kvm_exc_entry)
-	UNWIND_HINT_UNDEFINED
+	UNWIND_HINT_END_OF_STACK
 	csrwr	a2,   KVM_TEMP_KS
 	csrrd	a2,   KVM_VCPU_KS
 	addi.d	a2,   a2, KVM_VCPU_ARCH