From 5294117078691549e84e26a96a2d647debabf7db Mon Sep 17 00:00:00 2001
From: Igor Mammedov <imammedo@redhat.com>
Date: Wed, 12 Jan 2022 08:03:31 -0500
Subject: [PATCH 09/12] acpi: fix OEM ID/OEM Table ID padding

RH-Author: Igor Mammedov <imammedo@redhat.com>
RH-MergeRequest: 129: acpi: fix QEMU crash when started with SLIC table
RH-Commit: [7/10] 3404492ef0094c8d5d2db0c82f1159705f9de7c7
RH-Bugzilla: 2059311
RH-Acked-by: Jon Maloy <jmaloy@redhat.com>
RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
RH-Acked-by: MST <None>

Commit [2] broke original '\0' padding of OEM ID and OEM Table ID
fields in headers of ACPI tables. While it doesn't have impact on
default values since QEMU uses 6 and 8 characters long values
respectively, it broke usecase where IDs are provided on QEMU CLI.
It shouldn't affect guest (but may cause licensing verification
issues in guest OS).
One of the broken usecases is user supplied SLIC table with IDs
shorter than max possible length, where [2] mangles IDs with extra
spaces in RSDT and FADT tables whereas guest OS expects those to
mirror the respective values of the used SLIC table.

Fix it by replacing whitespace padding with '\0' padding in
accordance with [1] and expectations of guest OS

1) ACPI spec, v2.0b
       17.2 AML Grammar Definition
       ...
       //OEM ID of up to 6 characters. If the OEM ID is
       //shorter than 6 characters, it can be terminated
       //with a NULL character.

2)
Fixes: 602b458201 ("acpi: Permit OEM ID and OEM table ID fields to be changed")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/707
Reported-by: Dmitry V. Orekhov <dima.orekhov@gmail.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Cc: qemu-stable@nongnu.org
Message-Id: <20220112130332.1648664-4-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Tested-by: Dmitry V. Orekhov dima.orekhov@gmail.com
(cherry picked from commit 748c030f360a940fe0c9382c8ca1649096c3a80d)
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/acpi/aml-build.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index b3b3310df3..65148d5b9d 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1724,9 +1724,9 @@ void acpi_table_begin(AcpiTable *desc, GArray *array)
     build_append_int_noprefix(array, 0, 4); /* Length */
     build_append_int_noprefix(array, desc->rev, 1); /* Revision */
     build_append_int_noprefix(array, 0, 1); /* Checksum */
-    build_append_padded_str(array, desc->oem_id, 6, ' '); /* OEMID */
+    build_append_padded_str(array, desc->oem_id, 6, '\0'); /* OEMID */
     /* OEM Table ID */
-    build_append_padded_str(array, desc->oem_table_id, 8, ' ');
+    build_append_padded_str(array, desc->oem_table_id, 8, '\0');
     build_append_int_noprefix(array, 1, 4); /* OEM Revision */
     g_array_append_vals(array, ACPI_BUILD_APPNAME8, 4); /* Creator ID */
     build_append_int_noprefix(array, 1, 4); /* Creator Revision */
-- 
2.27.0