[PATCH v3] Fix acpi_dmar_zap/reinstate() (fixes S3 regression)

[Tomasz Wroblewski <tomasz.wroblewski@citrix.com>]

[-- Attachment #1: Type: text/plain, Size: 1315 bytes --]

Thanks, attaching version 3 of the patch using your suggestions, which 
simplify it considerably. This one uses map_pages_to_xen in favour of 
ioremap, so it works on both tip as well as older trees from before 
ioremap() rework (tested both).

Changes from v2/v1:
- keeping global dmar_table pointer and initializing it in acpi_dmar_init()
- use map_pages_to_xen to add a static mapping (instead of ioremap)
- moved acpi_get_table_physical_location to tbxface.c. Added instance 
argument to make it symmetric with acpi_get_table.
- coding convention fixes

Commit message:

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>


[-- Attachment #2: fix-dmar-zap-reinstate-v3.patch --]
[-- Type: text/x-patch, Size: 2867 bytes --]

diff -r 4b476378fc35 xen/drivers/acpi/tables/tbxface.c
--- a/xen/drivers/acpi/tables/tbxface.c	Mon Jan 21 17:03:10 2013 +0000
+++ b/xen/drivers/acpi/tables/tbxface.c	Tue Jan 22 17:13:06 2013 +0000
@@ -205,3 +205,44 @@
 
 	return (AE_NOT_FOUND);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_get_table_physical_location
+ *
+ * PARAMETERS:  Signature           - ACPI signature of needed table
+ *              Instance            - Which instance (for SSDTs)
+ *              out_addr            - Where the table's physical address is returned
+ *              out_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_physical_location(char *signature,
+				 acpi_native_uint instance,
+				 acpi_physical_address *out_addr, u32 *out_len)
+{
+	acpi_native_uint i;
+	acpi_native_uint j;
+
+	if (!signature || !out_addr || !out_len) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	for (i = 0, 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;
+		}
+		*out_addr = acpi_gbl_root_table_list.tables[i].address;
+		*out_len = acpi_gbl_root_table_list.tables[i].length;
+		return AE_OK;
+	}
+
+	return AE_NOT_FOUND;
+}
diff -r 4b476378fc35 xen/drivers/passthrough/vtd/dmar.c
--- a/xen/drivers/passthrough/vtd/dmar.c	Mon Jan 21 17:03:10 2013 +0000
+++ b/xen/drivers/passthrough/vtd/dmar.c	Tue Jan 22 17:13:06 2013 +0000
@@ -823,7 +823,17 @@
 
 int __init acpi_dmar_init(void)
 {
-    acpi_get_table(ACPI_SIG_DMAR, 0, &dmar_table);
+    acpi_physical_address dmar_addr;
+    u32 dmar_len;
+    if ( !acpi_get_table_physical_location(
+             ACPI_SIG_DMAR, 0, &dmar_addr, &dmar_len) )
+    {
+        map_pages_to_xen((unsigned long)__va(dmar_addr), PFN_DOWN(dmar_addr),
+                         PFN_UP(dmar_addr) - PFN_DOWN(dmar_addr) + 1,
+                         PAGE_HYPERVISOR);
+        dmar_table = (struct acpi_table_header*) __va(dmar_addr);
+    }
+
     return parse_dmar_table(acpi_parse_dmar);
 }
 
diff -r 4b476378fc35 xen/include/acpi/acpixf.h
--- a/xen/include/acpi/acpixf.h	Mon Jan 21 17:03:10 2013 +0000
+++ b/xen/include/acpi/acpixf.h	Tue Jan 22 17:13:06 2013 +0000
@@ -77,6 +77,10 @@
 acpi_get_table(acpi_string signature,
 	       acpi_native_uint instance, struct acpi_table_header **out_table);
 
+acpi_status
+acpi_get_table_physical_location(char *signature,
+				 acpi_native_uint instance,
+				 acpi_physical_address *out_addr, u32 *out_len);
 /*
  * Namespace and name interfaces
  */

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel