From 7715635d018351e0a5c4c25aec2c71a2fe3b9e69 Mon Sep 17 00:00:00 2001
From: Jon Maloy <jmaloy@redhat.com>
Date: Tue, 9 May 2023 10:29:03 -0400
Subject: [PATCH 06/15] bcm2835_property: disable reentrancy detection for
 iomem

RH-Author: Jon Maloy <jmaloy@redhat.com>
RH-MergeRequest: 277: memory: prevent dma-reentracy issues
RH-Bugzilla: 1999236
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [6/12] 4d6187430ca1c4309a36824c0c6815d2a763db1a (redhat/rhel/src/qemu-kvm/jons-qemu-kvm-2)

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1999236
Upstream: Merged
CVE: CVE-2021-3750

commit 985c4a4e547afb9573b6bd6843d20eb2c3d1d1cd
Author: Alexander Bulekov <alxndr@bu.edu>
Date:   Thu Apr 27 17:10:11 2023 -0400

    bcm2835_property: disable reentrancy detection for iomem

    As the code is designed for re-entrant calls from bcm2835_property to
    bcm2835_mbox and back into bcm2835_property, mark iomem as
    reentrancy-safe.

    Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
    Reviewed-by: Thomas Huth <thuth@redhat.com>
    Message-Id: <20230427211013.2994127-7-alxndr@bu.edu>
    Signed-off-by: Thomas Huth <thuth@redhat.com>

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
---
 hw/misc/bcm2835_property.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c
index 73941bdae9..022b5a849c 100644
--- a/hw/misc/bcm2835_property.c
+++ b/hw/misc/bcm2835_property.c
@@ -377,6 +377,13 @@ static void bcm2835_property_init(Object *obj)
 
     memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_property_ops, s,
                           TYPE_BCM2835_PROPERTY, 0x10);
+
+    /*
+     * bcm2835_property_ops call into bcm2835_mbox, which in-turn reads from
+     * iomem. As such, mark iomem as re-entracy safe.
+     */
+    s->iomem.disable_reentrancy_guard = true;
+
     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
     sysbus_init_irq(SYS_BUS_DEVICE(s), &s->mbox_irq);
 }
-- 
2.37.3