fix a few bugs in scheduling and synchronization, separate OVMF_VARS for debug

code/kernel/mm_virt.c

@@ -243,7 +243,7 @@ static void* HeapAlloc(HEAP* h, size_t size) {
     if (!size) return (void *)0;
     size = (size + 7) & ~7ULL;   // 8-byte align
 
-    KeAcquireSpinlock(&h->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&h->Lock);
 
     // Best-fit search.
     BLOCK_HDR* best = (BLOCK_HDR *)0;
@@ -256,14 +256,14 @@ static void* HeapAlloc(HEAP* h, size_t size) {
 
     if (!best) {
         if (!HeapGrow(h, size + OVERHEAD)) {
-            KeReleaseSpinlock(&h->Lock);
+            KeReleaseSpinlock(&h->Lock, flags);
             return (void *)0;
         }
         // Re-search; HeapGrow inserted at the front.
         best = h->FreeList;
         while (best && best->Size < size) best = best->NextFree;
         if (!best) {
-            KeReleaseSpinlock(&h->Lock);
+            KeReleaseSpinlock(&h->Lock, flags);
             return (void *)0;
         }
     }
@@ -292,7 +292,7 @@ static void* HeapAlloc(HEAP* h, size_t size) {
     HdrToFtr(best)->Magic = BLOCK_MAGIC;
     HdrToFtr(best)->Size  = best->Size;
 
-    KeReleaseSpinlock(&h->Lock);
+    KeReleaseSpinlock(&h->Lock, flags);
     return (char *)best + HDR_SIZE;
 }
 
@@ -301,7 +301,7 @@ static void HeapFree(HEAP* h, void* ptr) {
     BLOCK_HDR* blk = (BLOCK_HDR *)((char *)ptr - HDR_SIZE);
     if (blk->Magic != BLOCK_MAGIC || blk->Free) return;   // double-free / corrupt
 
-    KeAcquireSpinlock(&h->Lock);
+    uintptr_t flags = KeAcquireSpinlock(&h->Lock);
 
     blk->Free = 1;
 
@@ -338,7 +338,7 @@ static void HeapFree(HEAP* h, void* ptr) {
     HdrToFtr(blk)->Free  = 1;
     HdrToFtr(blk)->Magic = BLOCK_MAGIC;
 
-    KeReleaseSpinlock(&h->Lock);
+    KeReleaseSpinlock(&h->Lock, flags);
 }
 
 static void* HeapRealloc(HEAP* h, void* ptr, size_t new_size) {