[Xen-changelog] [xen master] tools: arm: report an error if the guest RAM is too large

[patchbot@xxxxxxx]

commit 5a959f44ed03398870b6ec0dfebb59dcd5981f94
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Thu May 22 10:46:37 2014 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Mon Jun 2 14:56:20 2014 +0100

    tools: arm: report an error if the guest RAM is too large
    
    Due to the layout of the guest physical address space we cannot support more
    than 768M of RAM before overrunning the area set aside for the grant table. 
Due
    to the presence of the magic pages at the end of the RAM region guests are
    actually limited to 767M.
    
    Catch this case during domain build and fail gracefully instead of obscurely
    later on.
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>
    Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 tools/libxc/xc_dom_arm.c      |    9 +++++++++
 xen/include/public/arch-arm.h |    3 ++-
 2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 60ac51a..d5831a2 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -272,6 +272,15 @@ int arch_setup_meminit(struct xc_dom_image *dom)
         return -1;
     }
 
+    if ( ramsize > GUEST_RAM_SIZE - NR_MAGIC_PAGES*XC_PAGE_SIZE )
+    {
+        DOMPRINTF("%s: ram size is too large for guest address space: "
+                  "%"PRIx64" > %llx",
+                  __FUNCTION__, ramsize,
+                  GUEST_RAM_SIZE - NR_MAGIC_PAGES*XC_PAGE_SIZE);
+        return -1;
+    }
+
     rc = set_mode(dom->xch, dom->guest_domid, dom->guest_type);
     if ( rc )
         return rc;
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index 7496556..dd53c94 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -369,7 +369,8 @@ typedef uint64_t xen_callback_t;
 #define GUEST_GICC_BASE   0x2c002000ULL
 #define GUEST_GICC_SIZE   0x100ULL
 
-#define GUEST_RAM_BASE    0x80000000ULL
+#define GUEST_RAM_BASE    0x80000000ULL /* 768M @ 2GB */
+#define GUEST_RAM_SIZE    0x30000000ULL
 
 #define GUEST_GNTTAB_BASE 0xb0000000ULL
 #define GUEST_GNTTAB_SIZE 0x00020000ULL
--
generated by git-patchbot for /home/xen/git/xen.git#master

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