block: vhdx - add region overlap detection for image files

Regions in the image file cannot overlap - the log, region tables,
and metdata must all be unique and non-overlapping.

This adds region checking by means of a QLIST; there can be a variable
number of regions and metadata (there may be metadata or region tables
that we do not recognize / know about, but are not required).

This adds the capability to register a region for later checking, and
to check against registered regions for any overlap.

Also, if neither the BAT or Metadata region tables are found, return
error.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/block/vhdx.h b/block/vhdx.h
index 584ebec8fc..d9065595fc 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -230,6 +230,7 @@ typedef struct QEMU_PACKED VHDXLogDataSector {
    other bits are reserved */
 #define VHDX_BAT_STATE_BIT_MASK 0x07
 #define VHDX_BAT_FILE_OFF_BITS (64 - 44)
+#define VHDX_BAT_FILE_OFF_MASK  0xFFFFFFFFFFF00000 /* upper 44 bits */
 typedef uint64_t VHDXBatEntry;
 
 /* ---- METADATA REGION STRUCTURES ---- */
@@ -334,6 +335,12 @@ typedef struct VHDXLogEntries {
     uint32_t tail;
 } VHDXLogEntries;
 
+typedef struct VHDXRegionEntry {
+    uint64_t start;
+    uint64_t end;
+    QLIST_ENTRY(VHDXRegionEntry) entries;
+} VHDXRegionEntry;
+
 typedef struct BDRVVHDXState {
     CoMutex lock;
 
@@ -374,6 +381,8 @@ typedef struct BDRVVHDXState {
     VHDXParentLocatorEntry *parent_entries;
 
     Error *migration_blocker;
+
+    QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
 } BDRVVHDXState;
 
 void vhdx_guid_generate(MSGUID *guid);