[xen staging] revert "tools/libs/guest: fix max_pfn setting in map_p2m()"

[patchbot@xxxxxxx]

commit 60d82f4bb0a22eb8765d33f87207afab25bc2396
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Mon Jun 14 14:39:52 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jun 14 14:39:52 2021 +0200

    revert "tools/libs/guest: fix max_pfn setting in map_p2m()"
    
    The reasoning for commit 7bd8989ab77b6a ("tools/libs/guest: fix max_pfn
    setting in map_p2m()") was wrong.
    
    The max_pfn field in shared_info is misnamed, it has the semantics of
    num_pfns, which is hidden at least partially in Linux, as the kernel is
    (wrongly) treating it like the highest used pfn in some places.
    
    So revert above commit.
    
    Fixes: 7bd8989ab77b6a ("tools/libs/guest: fix max_pfn setting in map_p2m()")
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/libs/guest/xg_sr_save_x86_pv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/libs/guest/xg_sr_save_x86_pv.c 
b/tools/libs/guest/xg_sr_save_x86_pv.c
index dae7f2817f..4964f1f7b8 100644
--- a/tools/libs/guest/xg_sr_save_x86_pv.c
+++ b/tools/libs/guest/xg_sr_save_x86_pv.c
@@ -468,7 +468,7 @@ static int map_p2m(struct xc_sr_context *ctx)
 
     ctx->x86.pv.p2m_generation = ~0ULL;
     ctx->x86.pv.max_pfn = GET_FIELD(ctx->x86.pv.shinfo, arch.max_pfn,
-                                    ctx->x86.pv.width);
+                                    ctx->x86.pv.width) - 1;
     p2m_cr3 = GET_FIELD(ctx->x86.pv.shinfo, arch.p2m_cr3, ctx->x86.pv.width);
 
     return p2m_cr3 ? map_p2m_list(ctx, p2m_cr3) : map_p2m_tree(ctx);
--
generated by git-patchbot for /home/xen/git/xen.git#staging