fix acpi_dmar_zap/reinstate() (fixes S3 regression)

Fix S3 regression introduced by cs 23013:65d26504e843 (ACPI: large
cleanup). The dmar virtual pointer returned from acpi_get_table cannot
be safely stored away and used later, as the underlying
acpi_os_map_memory / __acpi_map_table functions overwrite the mapping
causing it to point to different tables than dmar (last fetched table is
used). This subsequently causes acpi_dmar_reinstate() and
acpi_dmar_zap() to write data to wrong table, causing its corruption and
problems with consecutive s3 resumes.

Added a new function to fetch ACPI table physical address, and
establishing separate static mapping for dmar_table pointer instead of
using acpi_get_table().

Signed-off-by: Tomasz Wroblewski <tomasz.wroblewski@citrix.com>

Added call to acpi_tb_verify_table(). Fixed page count passed to
map_pages_to_xen(). Cosmetic changes.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Committed-by: Jan Beulich <jbeulich@suse.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/xen/drivers/acpi/tables/tbxface.c b/xen/drivers/acpi/tables/tbxface.c
index df6eeba7e1..1602bb2837 100644
--- a/xen/drivers/acpi/tables/tbxface.c
+++ b/xen/drivers/acpi/tables/tbxface.c
@@ -205,3 +205,51 @@ acpi_get_table(char *signature,
 
 	return (AE_NOT_FOUND);
 }
+
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_get_table_phys
+ *
+ * PARAMETERS:  signature      - ACPI signature of needed table
+ *              instance       - Which instance (for SSDTs)
+ *              addr           - Where the table's physical address is returned
+ *              len            - Where the length of table is returned
+ *
+ * RETURN:      Status, pointer and length of table
+ *
+ * DESCRIPTION: Finds physical address and length of ACPI table
+ *
+ *****************************************************************************/
+acpi_status __init
+acpi_get_table_phys(acpi_string signature, acpi_native_uint instance,
+		     acpi_physical_address *addr, acpi_native_uint *len)
+{
+	acpi_native_uint i, j;
+	acpi_status status;
+
+	if (!signature || !addr || !len)
+		return AE_BAD_PARAMETER;
+
+	for (i = j = 0; i < acpi_gbl_root_table_list.count; i++) {
+		if (!ACPI_COMPARE_NAME(
+				&acpi_gbl_root_table_list.tables[i].signature,
+				signature))
+			continue;
+
+		if (++j < instance)
+			continue;
+
+		status =
+		    acpi_tb_verify_table(&acpi_gbl_root_table_list.tables[i]);
+		if (ACPI_SUCCESS(status)) {
+			*addr = acpi_gbl_root_table_list.tables[i].address;
+			*len = acpi_gbl_root_table_list.tables[i].length;
+		}
+
+		acpi_gbl_root_table_list.tables[i].pointer = NULL;
+
+		return status;
+	}
+
+	return AE_NOT_FOUND;
+}