From 2bed4683942626b8e3bcf2721710d6f26322a470 Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Thu, 2 Feb 2017 18:19:32 +0100
Subject: [PATCH 3/9] vhost: skip ROM sections
RH-Author: Laurent Vivier <lvivier@redhat.com>
Message-id: <20170202181932.551-4-lvivier@redhat.com>
Patchwork-id: 73520
O-Subject: [RHEV-7.3.z qemu-kvm-rhev PATCH 3/3] vhost: skip ROM sections
Bugzilla: 1420456
RH-Acked-by: David Gibson <dgibson@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
From: "Michael S. Tsirkin" <mst@redhat.com>
vhost does not support RO protections on memory at the moment - adding
ROMs would mean that e.g. a buggy guest might change them in-memory - a
condition from which guest reset does not recover. Not nice.
We also definitely don't want to try logging writes into ROMs -
in particular guests set very high addresses for ROM BARs
so logging these writes would waste a lot of memory.
Maybe ROMs could be supported with the iotlb variant -
not sure, but there seems to be no good reason for virtio
to try to do DMA from ROM. So let's just skip ROM memory.
Suggested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
(cherry picked from commit d56ec1e98c0005933fe677d633484297f422691a)
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1404673
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
hw/virtio/vhost.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 3b4db14..b8f1d3f 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -542,7 +542,8 @@ static void vhost_set_memory(MemoryListener *listener,
static bool vhost_section(MemoryRegionSection *section)
{
- return memory_region_is_ram(section->mr);
+ return memory_region_is_ram(section->mr) &&
+ !memory_region_is_rom(section->mr);
}
static void vhost_begin(MemoryListener *listener)
--
1.8.3.1