[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[PATCH] xen/device-tree: Allow exact match for overlapping regions



There are some cases where the device tree exposes a memory range
in both /memreserve/ and reserved-memory node, in this case the
current code will stop Xen to boot since it will find that the
latter range is clashing with the already recorded /memreserve/
ranges.

Furthermore, u-boot lists boot modules ranges, such as ramdisk,
in the /memreserve/ part and even in this case this will prevent
Xen to boot since it will see that the module memory range that
it is going to add in 'add_boot_module' clashes with a /memreserve/
range.

When Xen populate the data structure that tracks the memory ranges,
it also adds a memory type described in 'enum membank_type', so
in order to fix this behavior, allow the 'check_reserved_regions_overlap'
function to check for exact memory range match given a specific memory
type; allowing reserved-memory node ranges and boot modules to have an
exact match with ranges from /memreserve/.

While there, set a type for the memory recorded during ACPI boot.

Fixes: 53dc37829c31 ("xen/arm: Add DT reserve map regions to 
bootinfo.reserved_mem")
Reported-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>
Reported-by: Grygorii Strashko <grygorii_strashko@xxxxxxxx>
Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
I tested this patch adding the same range in a /memreserve/ entry and
/reserved-memory node, and by letting u-boot pass a ramdisk.
I've also tested that a configuration running static shared memory still works
fine.
---
 xen/arch/arm/efi/efi-boot.h       |  3 +-
 xen/arch/arm/static-shmem.c       |  2 +-
 xen/common/device-tree/bootfdt.c  |  9 +++++-
 xen/common/device-tree/bootinfo.c | 48 ++++++++++++++++++++++++-------
 xen/include/xen/bootfdt.h         |  9 +++++-
 5 files changed, 57 insertions(+), 14 deletions(-)

diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 199f5260229d..d35c991c856f 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -167,13 +167,14 @@ static bool __init meminfo_add_bank(struct membanks *mem,
     if ( mem->nr_banks >= mem->max_banks )
         return false;
 #ifdef CONFIG_ACPI
-    if ( check_reserved_regions_overlap(start, size) )
+    if ( check_reserved_regions_overlap(start, size, MEMBANK_NONE) )
         return false;
 #endif
 
     bank = &mem->bank[mem->nr_banks];
     bank->start = start;
     bank->size = size;
+    bank->type = MEMBANK_DEFAULT;
 
     mem->nr_banks++;
 
diff --git a/xen/arch/arm/static-shmem.c b/xen/arch/arm/static-shmem.c
index aa80756c3ca5..149ed4b0a5ba 100644
--- a/xen/arch/arm/static-shmem.c
+++ b/xen/arch/arm/static-shmem.c
@@ -696,7 +696,7 @@ int __init process_shm_node(const void *fdt, int node, 
uint32_t address_cells,
         if (i < mem->max_banks)
         {
             if ( (paddr != INVALID_PADDR) &&
-                 check_reserved_regions_overlap(paddr, size) )
+                 check_reserved_regions_overlap(paddr, size, MEMBANK_NONE) )
                 return -EINVAL;
 
             /* Static shared memory shall be reserved from any other use. */
diff --git a/xen/common/device-tree/bootfdt.c b/xen/common/device-tree/bootfdt.c
index 927f59c64b0d..fb3a6ab95a22 100644
--- a/xen/common/device-tree/bootfdt.c
+++ b/xen/common/device-tree/bootfdt.c
@@ -176,8 +176,15 @@ static int __init device_tree_get_meminfo(const void *fdt, 
int node,
     for ( i = 0; i < banks && mem->nr_banks < mem->max_banks; i++ )
     {
         device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
+        /*
+         * Some valid device trees, such as those generated by OpenPOWER
+         * skiboot firmware, expose all reserved memory regions in the
+         * FDT memory reservation block AND in the reserved-memory node which
+         * has already been parsed. Thus, any matching overlaps in the
+         * reserved_mem banks should be ignored.
+         */
         if ( mem == bootinfo_get_reserved_mem() &&
-             check_reserved_regions_overlap(start, size) )
+             check_reserved_regions_overlap(start, size, MEMBANK_FDT_RESVMEM) )
             return -EINVAL;
         /* Some DT may describe empty bank, ignore them */
         if ( !size )
diff --git a/xen/common/device-tree/bootinfo.c 
b/xen/common/device-tree/bootinfo.c
index f2e6a1145b7c..05038075e835 100644
--- a/xen/common/device-tree/bootinfo.c
+++ b/xen/common/device-tree/bootinfo.c
@@ -99,7 +99,8 @@ static void __init dt_unreserved_regions(paddr_t s, paddr_t e,
  */
 static bool __init meminfo_overlap_check(const struct membanks *mem,
                                          paddr_t region_start,
-                                         paddr_t region_size)
+                                         paddr_t region_size,
+                                         enum membank_type allow_match_type)
 {
     paddr_t bank_start = INVALID_PADDR, bank_end = 0;
     paddr_t region_end = region_start + region_size;
@@ -113,12 +114,16 @@ static bool __init meminfo_overlap_check(const struct 
membanks *mem,
         if ( INVALID_PADDR == bank_start || region_end <= bank_start ||
              region_start >= bank_end )
             continue;
-        else
-        {
-            printk("Region: [%#"PRIpaddr", %#"PRIpaddr") overlapping with 
bank[%u]: [%#"PRIpaddr", %#"PRIpaddr")\n",
-                   region_start, region_end, i, bank_start, bank_end);
-            return true;
-        }
+
+        if ( (allow_match_type != MEMBANK_NONE) &&
+             (region_start == bank_start) && (region_end == bank_end) &&
+             (allow_match_type == mem->bank[i].type) )
+            continue;
+
+        printk("Region: [%#"PRIpaddr", %#"PRIpaddr") overlapping with 
bank[%u]: [%#"PRIpaddr", %#"PRIpaddr")\n",
+                region_start, region_end, i, bank_start, bank_end);
+        return true;
+
     }
 
     return false;
@@ -169,9 +174,14 @@ void __init fw_unreserved_regions(paddr_t s, paddr_t e,
  * with the existing reserved memory regions defined in bootinfo.
  * Return true if the input physical address range is overlapping with any
  * existing reserved memory regions, otherwise false.
+ * The 'allow_match_type' parameter can be used to allow exact match of a
+ * region with another memory region already recorded, but it needs to be used
+ * only on memory regions that allows a type (reserved_mem, acpi). For all the
+ * other cases, passing 'MEMBANK_NONE' will disable the exact match.
  */
 bool __init check_reserved_regions_overlap(paddr_t region_start,
-                                           paddr_t region_size)
+                                           paddr_t region_size,
+                                           enum membank_type allow_match_type)
 {
     const struct membanks *mem_banks[] = {
         bootinfo_get_reserved_mem(),
@@ -190,8 +200,21 @@ bool __init check_reserved_regions_overlap(paddr_t 
region_start,
      * shared memory banks (when static shared memory feature is enabled)
      */
     for ( i = 0; i < ARRAY_SIZE(mem_banks); i++ )
-        if ( meminfo_overlap_check(mem_banks[i], region_start, region_size) )
+    {
+        enum membank_type type = allow_match_type;
+
+#ifdef CONFIG_STATIC_SHM
+        /*
+         * Static shared memory banks don't have a type, so for them disable
+         * the exact match check.
+         */
+        if (mem_banks[i] == bootinfo_get_shmem())
+            type = MEMBANK_NONE;
+#endif
+        if ( meminfo_overlap_check(mem_banks[i], region_start, region_size,
+                                   type) )
             return true;
+    }
 
     /* Check if input region is overlapping with bootmodules */
     if ( bootmodules_overlap_check(&bootinfo.modules,
@@ -216,7 +239,12 @@ struct bootmodule __init *add_boot_module(bootmodule_kind 
kind,
         return NULL;
     }
 
-    if ( check_reserved_regions_overlap(start, size) )
+    /*
+     * u-boot adds boot module such as ramdisk to the /memreserve/, since these
+     * ranges are saved in reserved_mem at this stage, allow an eventual exact
+     * match with MEMBANK_FDT_RESVMEM banks.
+     */
+    if ( check_reserved_regions_overlap(start, size, MEMBANK_FDT_RESVMEM) )
         return NULL;
 
     for ( i = 0 ; i < mods->nr_mods ; i++ )
diff --git a/xen/include/xen/bootfdt.h b/xen/include/xen/bootfdt.h
index 16fa05f38f38..8f8a7ad882a4 100644
--- a/xen/include/xen/bootfdt.h
+++ b/xen/include/xen/bootfdt.h
@@ -23,6 +23,12 @@ typedef enum {
 }  bootmodule_kind;
 
 enum membank_type {
+    /*
+     * The MEMBANK_NONE type is a special placeholder that should not be 
applied
+     * to a memory bank, it is used as a special value in some function in 
order
+     * to disable some feature.
+     */
+    MEMBANK_NONE = -1,
     /*
      * The MEMBANK_DEFAULT type refers to either reserved memory for the
      * device/firmware (when the bank is in 'reserved_mem') or any RAM (when
@@ -158,7 +164,8 @@ struct bootinfo {
 extern struct bootinfo bootinfo;
 
 bool check_reserved_regions_overlap(paddr_t region_start,
-                                    paddr_t region_size);
+                                    paddr_t region_size,
+                                    enum membank_type allow_match_type);
 
 struct bootmodule *add_boot_module(bootmodule_kind kind,
                                    paddr_t start, paddr_t size, bool domU);
-- 
2.34.1




 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.