[PATCH v4 2/2] x86/dmar: zap DMAR signature for dom0 once in TBOOT case

[PATCH v4 2/2] x86/dmar: zap DMAR signature for dom0 once in TBOOT case

[Zhenzhong Duan]

Commit 6c298ecc1f ("vtd: Reinstate ACPI DMAR on system shutdown or
S3/S4/S5") did everything for acpi_dmar_zap() call to be unnecessary,
except for invoking the function from acpi_parse_dmar(), which
123c779379 ("VTd/dmar: Tweak how the DMAR table is clobbered")
added several years later.

Some stale comments are also removed, No functional change.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
---
v4: fixup description per Jan

 xen/arch/x86/tboot.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index d5a5292..1006f95 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -461,8 +461,6 @@ int __init tboot_parse_dmar_table(acpi_table_handler dmar_handler)
     if ( txt_heap_base == 0 )
         return 1;
 
-    /* map TXT heap into Xen addr space */
-
     /* walk heap to SinitMleData */
     pa = txt_heap_base;
     /* skip BiosData */
@@ -490,10 +488,6 @@ int __init tboot_parse_dmar_table(acpi_table_handler dmar_handler)
     rc = dmar_handler(dmar_table);
     xfree(dmar_table);
 
-    /* acpi_parse_dmar() zaps APCI DMAR signature in TXT heap table */
-    /* but dom0 will read real table, so must zap it there too */
-    acpi_dmar_zap();
-
     return rc;
 }
 
-- 
1.7.3

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