tools/libs/guest: fix max_pfn setting in map_p2m()

When setting the highest pfn used in the guest, don't subtract 1 from
the value read from the shared_info data. The value read already is
the correct pfn.

Fixes: 91e204d37f ("libxc: try to find last used pfn when migrating")
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>

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) - 1;
+                                    ctx->x86.pv.width);
     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);