[PATCH 2/2] public/xen.h: Update comment for mmu_update hypercall

[Frediano Ziglio <freddy77@xxxxxxxxx>]

From: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>

The command is filtered from the address using this code

   cmd = req.ptr & (sizeof(l1_pgentry_t)-1);

l1_pgentry_t is always 64 bit so the 3 lower bits are used as
a command, not only 2 bits.

Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>
---
 xen/include/public/xen.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index d4f238c10b..0537d1f8f3 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -218,16 +218,16 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
  *                     x == 0 => PFD == DOMID_SELF
  *                     x != 0 => PFD == x - 1
  *
- * Sub-commands: ptr[1:0] specifies the appropriate MMU_* command.
+ * Sub-commands: ptr[2:0] specifies the appropriate MMU_* command.
  * -------------
- * ptr[1:0] == MMU_NORMAL_PT_UPDATE:
+ * ptr[2:0] == MMU_NORMAL_PT_UPDATE:
  * Updates an entry in a page table belonging to PFD. If updating an L1 table,
  * and the new table entry is valid/present, the mapped frame must belong to
  * FD. If attempting to map an I/O page then the caller assumes the privilege
  * of the FD.
  * FD == DOMID_IO: Permit /only/ I/O mappings, at the priv level of the caller.
  * FD == DOMID_XEN: Map restricted areas of Xen's heap space.
- * ptr[:2]  -- Machine address of the page-table entry to modify.
+ * ptr[:3]  -- Machine address of the page-table entry to modify.
  * val      -- Value to write.
  *
  * There also certain implicit requirements when using this hypercall. The
@@ -264,17 +264,17 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
  * mentioned above. The argument is MMUEXT_UNPIN_TABLE for all levels and the
  * pagetable MUST not be in use (meaning that the cr3 is not set to it).
  *
- * ptr[1:0] == MMU_MACHPHYS_UPDATE:
+ * ptr[2:0] == MMU_MACHPHYS_UPDATE:
  * Updates an entry in the machine->pseudo-physical mapping table.
- * ptr[:2]  -- Machine address within the frame whose mapping to modify.
+ * ptr[:3]  -- Machine address within the frame whose mapping to modify.
  *             The frame must belong to the FD, if one is specified.
  * val      -- Value to write into the mapping entry.
  *
- * ptr[1:0] == MMU_PT_UPDATE_PRESERVE_AD:
+ * ptr[2:0] == MMU_PT_UPDATE_PRESERVE_AD:
  * As MMU_NORMAL_PT_UPDATE above, but A/D bits currently in the PTE are ORed
  * with those in @val.
  *
- * ptr[1:0] == MMU_PT_UPDATE_NO_TRANSLATE:
+ * ptr[2:0] == MMU_PT_UPDATE_NO_TRANSLATE:
  * As MMU_NORMAL_PT_UPDATE above, but @val is not translated though FD
  * page tables.
  *
-- 
2.43.0