[xen staging] tools/libxg: Drop stale p2m logic from ARM's meminit()

[patchbot@xxxxxxx]

commit 928bffb6dd3f1b8a2355418f4c763a6fff714aa7
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Feb 11 17:45:21 2021 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Feb 17 12:37:08 2021 +0000

    tools/libxg: Drop stale p2m logic from ARM's meminit()
    
    Various version of gcc, when compiling with -Og, complain:
    
      xg_dom_arm.c: In function 'meminit':
      xg_dom_arm.c:420:19: error: 'p2m_size' may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
        420 |     dom->p2m_size = p2m_size;
            |     ~~~~~~~~~~~~~~^~~~~~~~~~
    
    This is actually entirely stale code since ee21f10d70^..97e34ad22d which
    removed the 1:1 identity p2m for translated domains.
    
    Drop the write of d->p2m_size, and the p2m_size local variable.  Reposition
    the p2m_size field in struct xc_dom_image and correct some stale
    documentation.
    
    This change really ought to have been part of the original cleanup series.
    
    No actual change to how ARM domains are constructed.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
    Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
---
 tools/include/xenguest.h      | 5 ++---
 tools/libs/guest/xg_dom_arm.c | 5 -----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/tools/include/xenguest.h b/tools/include/xenguest.h
index 775cf34c04..217022b6e7 100644
--- a/tools/include/xenguest.h
+++ b/tools/include/xenguest.h
@@ -145,6 +145,7 @@ struct xc_dom_image {
      * eventually copied into guest context.
      */
     xen_pfn_t *pv_p2m;
+    xen_pfn_t p2m_size;         /* number of pfns covered by pv_p2m */
 
     /* physical memory
      *
@@ -154,12 +155,10 @@ struct xc_dom_image {
      *
      * An ARM guest has GUEST_RAM_BANKS regions of RAM, with
      * rambank_size[i] pages in each. The lowest RAM address
-     * (corresponding to the base of the p2m arrays above) is stored
-     * in rambase_pfn.
+     * is stored in rambase_pfn.
      */
     xen_pfn_t rambase_pfn;
     xen_pfn_t total_pages;
-    xen_pfn_t p2m_size;         /* number of pfns covered by p2m */
     struct xc_dom_phys *phys_pages;
 #if defined (__arm__) || defined(__aarch64__)
     xen_pfn_t rambank_size[GUEST_RAM_BANKS];
diff --git a/tools/libs/guest/xg_dom_arm.c b/tools/libs/guest/xg_dom_arm.c
index 94948d2b20..b4c24f15fb 100644
--- a/tools/libs/guest/xg_dom_arm.c
+++ b/tools/libs/guest/xg_dom_arm.c
@@ -373,7 +373,6 @@ static int meminit(struct xc_dom_image *dom)
     const uint64_t modsize = dtb_size + ramdisk_size;
     const uint64_t ram128mb = bankbase[0] + (128<<20);
 
-    xen_pfn_t p2m_size;
     uint64_t bank0end;
 
     assert(dom->rambase_pfn << XC_PAGE_SHIFT == bankbase[0]);
@@ -409,16 +408,12 @@ static int meminit(struct xc_dom_image *dom)
 
         ramsize -= banksize;
 
-        p2m_size = ( bankbase[i] + banksize - bankbase[0] ) >> XC_PAGE_SHIFT;
-
         dom->rambank_size[i] = banksize >> XC_PAGE_SHIFT;
     }
 
     assert(dom->rambank_size[0] != 0);
     assert(ramsize == 0); /* Too much RAM is rejected above */
 
-    dom->p2m_size = p2m_size;
-
     /* setup initial p2m and allocate guest memory */
     for ( i = 0; i < GUEST_RAM_BANKS && dom->rambank_size[i]; i++ )
     {
--
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