[Xen-devel] [PATCH v3 5/8] tools: arm: prepare for multiple banks of guest RAM

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Prepare for adding more banks of guest RAM by renaming a bunch of variables
and defines as RAM0 etc.

Also in preparation switch to using GUEST_RAM0_BASE explicitly instead of
implicitly via dom->rambase_pfn (while asserting that they must be the same).
This makes the multiple bank case cleaner (although it looks a bit odd for
now).

GUEST_RAM_BASE is defined as the address of the lowest RAM bank, it is used in
tools/libxl/libxl_dom.c to call xc_dom_rambase_init().

Lastly for now ramsize (total size) and ram0size (size of first bank) are the
same, but use the appropriate one for each context.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
v3: Mention why GUEST_RAM_BASE is still defined.
v2: New patch
---
 tools/libxc/xc_dom_arm.c      |   25 +++++++++++++++----------
 xen/include/public/arch-arm.h |    8 ++++++--
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 74917c3..b218e0f 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -18,6 +18,7 @@
  * Copyright (c) 2011, Citrix Systems
  */
 #include <inttypes.h>
+#include <assert.h>
 
 #include <xen/xen.h>
 #include <xen/io/protocols.h>
@@ -255,9 +256,11 @@ int arch_setup_meminit(struct xc_dom_image *dom)
     uint64_t modbase;
 
     /* Convenient */
-    const uint64_t rambase = dom->rambase_pfn << XC_PAGE_SHIFT;
     const uint64_t ramsize = dom->total_pages << XC_PAGE_SHIFT;
-    const uint64_t ramend = rambase + ramsize;
+
+    const uint64_t ram0size = ramsize;
+    const uint64_t ram0end = GUEST_RAM0_BASE + ram0size;
+
     const uint64_t kernbase = dom->kernel_seg.vstart;
     const uint64_t kernend = ROUNDUP(dom->kernel_seg.vend, 21/*2MB*/);
     const uint64_t kernsize = kernend - kernbase;
@@ -266,20 +269,22 @@ int arch_setup_meminit(struct xc_dom_image *dom)
     const uint64_t ramdisk_size = dom->ramdisk_blob ?
         ROUNDUP(dom->ramdisk_size, XC_PAGE_SHIFT) : 0;
     const uint64_t modsize = dtb_size + ramdisk_size;
-    const uint64_t ram128mb = rambase + (128<<20);
+    const uint64_t ram128mb = GUEST_RAM0_BASE + (128<<20);
+
+    assert(dom->rambase_pfn << XC_PAGE_SHIFT == GUEST_RAM0_BASE);
 
-    if ( modsize + kernsize > ramsize )
+    if ( modsize + kernsize > ram0size )
     {
         DOMPRINTF("%s: Not enough memory for the kernel+dtb+initrd",
                   __FUNCTION__);
         return -1;
     }
 
-    if ( ramsize > GUEST_RAM_SIZE )
+    if ( ramsize > GUEST_RAM_MAX )
     {
         DOMPRINTF("%s: ram size is too large for guest address space: "
                   "%"PRIx64" > %"PRIx64,
-                  __FUNCTION__, ramsize, GUEST_RAM_SIZE);
+                  __FUNCTION__, ramsize, GUEST_RAM_MAX);
         return -1;
     }
 
@@ -319,11 +324,11 @@ int arch_setup_meminit(struct xc_dom_image *dom)
      * If changing this then consider
      * xen/arch/arm/kernel.c:place_modules as well.
      */
-    if ( ramend >= ram128mb + modsize && kernend < ram128mb )
+    if ( ram0end >= ram128mb + modsize && kernend < ram128mb )
         modbase = ram128mb;
-    else if ( ramend - modsize > kernend )
-        modbase = ramend - modsize;
-    else if (kernbase - rambase > modsize )
+    else if ( ram0end - modsize > kernend )
+        modbase = ram0end - modsize;
+    else if (kernbase - GUEST_RAM0_BASE > modsize )
         modbase = kernbase - modsize;
     else
         return -1;
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index d5090fb..41944fe 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -375,8 +375,12 @@ typedef uint64_t xen_callback_t;
 #define GUEST_MAGIC_BASE  0x39000000ULL
 #define GUEST_MAGIC_SIZE  0x01000000ULL
 
-#define GUEST_RAM_BASE    0x40000000ULL /* 3GB of RAM @ 1GB */
-#define GUEST_RAM_SIZE    0xc0000000ULL
+#define GUEST_RAM0_BASE   0x40000000ULL /* 3GB of RAM @ 1GB */
+#define GUEST_RAM0_SIZE   0xc0000000ULL
+
+#define GUEST_RAM_BASE    GUEST_RAM0_BASE /* Lowest RAM address */
+/* Largest amount of actual RAM, not including holes */
+#define GUEST_RAM_MAX     (GUEST_RAM0_SIZE)
 
 /* Interrupts */
 #define GUEST_TIMER_VIRT_PPI    27
-- 
1.7.10.4


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