xen, pvh: fix unbootable VMs by inlining memset() in xen_prepare_pvh()

If this memset() is not inlined than PVH early boot code can call
into KASAN-instrumented memset() which results in unbootable VMs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Juergen Gross <jgross@suse.com>
Message-ID: <20240802154253.482658-3-adobriyan@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

diff --git a/arch/x86/platform/pvh/enlighten.c b/arch/x86/platform/pvh/enlighten.c
index 944e0290f2c001810a16a2eee3c2e87a31ba48e0..2263885d16badd18eaf1788d6d0b9e5af49bf632 100644 (file)
--- a/arch/x86/platform/pvh/enlighten.c
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -130,7 +130,11 @@ void __init xen_prepare_pvh(void)
                BUG();
        }
 
-       memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
+       /*
+        * This must not compile to "call memset" because memset() may be
+        * instrumented.
+        */
+       __builtin_memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
 
        hypervisor_specific_init(xen_guest);