fix(agc-driver): keep a live-backed snapshot mismatch from failing the dispatch

core/libs/prx/libSceAgcDriver/Graphics/src/GuestBufferMemory.cpp

@@ -2582,7 +2582,25 @@ void GuestBufferMemory::AddSnapshot(const GuestMemorySnapshot& snapshot) {
         }
         const auto offset = static_cast<std::size_t>(snapshot.address - owner->begin);
         const auto* source = live ? reinterpret_cast<const std::byte*>(snapshot.address) : owner->snapshot.data() + offset;
-        Require(std::memcmp(source, snapshot.bytes.data(), snapshot.bytes.size()) == 0, "guest snapshot differs from registered memory");
+        if (std::memcmp(source, snapshot.bytes.data(), snapshot.bytes.size()) != 0) {
+            std::size_t first = 0;
+            while (first < snapshot.bytes.size() && source[first] == snapshot.bytes[first]) ++first;
+            char text[256];
+            std::snprintf(text, sizeof(text), "guest snapshot differs from registered memory: snapshot 0x%llx+0x%zx (%s region 0x%llx+0x%llx%s%s%s) differs first at +0x%zx", static_cast<unsigned long long>(snapshot.address), snapshot.bytes.size(), live ? "live" : "snapshot-backed", static_cast<unsigned long long>(owner->begin), static_cast<unsigned long long>(owner->end - owner->begin), owner->writable ? ", writable" : "", owner->hostBacked ? ", host-backed" : "", owner->mirror != nullptr ? ", mirrored" : "", first);
+            static const bool fatal = std::getenv("APS5_SNAPSHOT_CHECK_FATAL") != nullptr;
+            if (!live || fatal) throw std::runtime_error(text);
+            static std::mutex reportMutex;
+            static std::uint64_t mismatches = 0;
+            static auto lastReport = std::chrono::steady_clock::now() - std::chrono::seconds(60);
+            std::lock_guard lock(reportMutex);
+            ++mismatches;
+            const auto now = std::chrono::steady_clock::now();
+            if (now - lastReport >= std::chrono::seconds(10)) {
+                lastReport = now;
+                std::fprintf(stderr, "[gpu] %s; the live region serves the GPU (%llu mismatches so far; APS5_SNAPSHOT_CHECK_FATAL=1 fails the dispatch instead)\n", text, static_cast<unsigned long long>(mismatches));
+            }
+            return;
+        }
         if (profile) Snapshots().checked.fetch_add(1, std::memory_order_relaxed);
         return;
     }