From cf014f865509af3ec54d272965647a1739f2e1e3 Mon Sep 17 00:00:00 2001
From: IndecisiveTurtle <47210458+raphaelthegreat@users.noreply.github.com>
Date: Sun, 23 Mar 2025 01:19:15 +0200
Subject: [PATCH] liverpool: Ignore rewind packets with nullgpu

Rewind allows guest to self modify its command list and synchronize properly. Oftentimes the value its polling is supposed to be written by a compute shader, thus it will never happen with nullgpu. Ignore the packet to avoid freezing in such case
---
 src/video_core/amdgpu/liverpool.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/video_core/amdgpu/liverpool.cpp b/src/video_core/amdgpu/liverpool.cpp
index 23bec75f5..f12fbdbe5 100644
--- a/src/video_core/amdgpu/liverpool.cpp
+++ b/src/video_core/amdgpu/liverpool.cpp
@@ -655,6 +655,9 @@ Liverpool::Task Liverpool::ProcessGraphics(std::span<const u32> dcb, std::span<c
                 break;
             }
             case PM4ItOpcode::Rewind: {
+                if (!rasterizer) {
+                    break;
+                }
                 const PM4CmdRewind* rewind = reinterpret_cast<const PM4CmdRewind*>(header);
                 while (!rewind->Valid()) {
                     YIELD_GFX();
@@ -793,6 +796,9 @@ Liverpool::Task Liverpool::ProcessCompute(std::span<const u32> acb, u32 vqid) {
             break;
         }
         case PM4ItOpcode::Rewind: {
+            if (!rasterizer) {
+                break;
+            }
             const PM4CmdRewind* rewind = reinterpret_cast<const PM4CmdRewind*>(header);
             while (!rewind->Valid()) {
                 YIELD_ASC(vqid);