linux-kernel - [PATCH v4 3/4] kexec_file: Don't place kexec images on IORESOURCE_MEM_DRIVER

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Date:   Fri,  8 May 2020 10:42:16 +0200
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, linux-nvdimm@...ts.01.org,
        kexec@...ts.infradead.org, Vishal Verma <vishal.l.verma@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Pavel Tatashin <pasha.tatashin@...een.com>,
        David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>,
        Pankaj Gupta <pankaj.gupta.linux@...il.com>,
        Wei Yang <richard.weiyang@...il.com>,
        Baoquan He <bhe@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Eric Biederman <ebiederm@...ssion.com>,
        Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH v4 3/4] kexec_file: Don't place kexec images on IORESOURCE_MEM_DRIVER_MANAGED

Memory flagged with IORESOURCE_MEM_DRIVER_MANAGED is special - it won't be
part of the initial memmap of the kexec kernel and not all memory might be
accessible. Don't place any kexec images onto it.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@...il.com>
Cc: Wei Yang <richard.weiyang@...il.com>
Cc: Baoquan He <bhe@...hat.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Eric Biederman <ebiederm@...ssion.com>
Cc: Pavel Tatashin <pasha.tatashin@...een.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 kernel/kexec_file.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index faa74d5f6941..bb05fd52de85 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -540,6 +540,11 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
 	unsigned long sz = end - start + 1;
 
 	/* Returning 0 will take to next memory range */
+
+	/* Don't use memory that will be detected and handled by a driver. */
+	if (res->flags & IORESOURCE_MEM_DRIVER_MANAGED)
+		return 0;
+
 	if (sz < kbuf->memsz)
 		return 0;
 
-- 
2.25.4