OvmfPkg/XenPlatformPei: Reserve VGA memory region, to boot Linux

Linux panic if the VGA region isn't reserved. When Linux is booted on EFI system, it expects the memory at 0xa0000 to _not_ be conventional memory. Otherwise a variable isn't initialised properly and Linux panic when a virtual console/terminal is asked to be created. See for more detail: https://lists.xenproject.org/archives/html/xen-devel/2019-03/msg02139.html Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689 Signed-off-by: Anthony PERARD <[email protected]> Acked-by: Laszlo Ersek <[email protected]> Message-Id: <[email protected]>
WalonLi · Aug 21, 2019 · 77d35f5 · 77d35f5
1 parent 24465c3
commit 77d35f5
Showing 1 changed file with 16 additions and 0 deletions.
diff --git a/OvmfPkg/XenPlatformPei/Xen.c b/OvmfPkg/XenPlatformPei/Xen.c
@@ -294,6 +294,12 @@ XenPublishRamRegions (
   Status = XenGetE820Map (&E820Map, &E820EntriesCount);
   ASSERT_EFI_ERROR (Status);
 
+  AddMemoryBaseSizeHob (0, 0xA0000);
+  //
+  // Video memory + Legacy BIOS region, to allow Linux to boot.
+  //
+  AddReservedMemoryBaseSizeHob (0xA0000, BASE_1MB - 0xA0000, TRUE);
+
   LapicBase = PcdGet32 (PcdCpuLocalApicBaseAddress);
   LapicEnd = LapicBase + SIZE_1MB;
   AddIoMemoryRangeHob (LapicBase, LapicEnd);
@@ -312,6 +318,16 @@ XenPublishRamRegions (
     Base = ALIGN_VALUE (Entry->BaseAddr, (UINT64)EFI_PAGE_SIZE);
     End = (Entry->BaseAddr + Entry->Length) & ~(UINT64)EFI_PAGE_MASK;
 
+    //
+    // Ignore the first 1MB, this is handled before the loop.
+    //
+    if (Base < BASE_1MB) {
+      Base = BASE_1MB;
+    }
+    if (Base >= End) {
+      continue;
+    }
+
     switch (Entry->Type) {
     case EfiAcpiAddressRangeMemory:
       AddMemoryRangeHob (Base, End);