Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-and-misc-080620-1' into staging

Various testing and misc fixes:

  - header cleanups for plugins
  - support wider watchpoints
  - tweaks for unreliable and broken CI
  - docker image fixes and verion bumps
  - linux-user guest_base fixes
  - remove flex/bison from various test images

# gpg: Signature made Mon 08 Jun 2020 17:16:19 BST
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-and-misc-080620-1:
  scripts/coverity-scan: Remove flex/bison packages
  cirrus-ci: Remove flex/bison packages
  tests/vm: Remove flex/bison packages
  tests/docker: Remove flex/bison packages
  linux-user: detect overflow of MAP_FIXED mmap
  tests/tcg: add simple commpage test case
  linux-user: deal with address wrap for ARM_COMMPAGE on 32 bit
  linux-user: provide fallback pgd_find_hole for bare chroots
  hw/virtio/vhost: re-factor vhost-section and allow DIRTY_MEMORY_CODE
  docker: update Ubuntu to 20.04
  tests/docker: fix pre-requisite for debian-tricore-cross
  .shippable: temporaily disable some cross builds
  .travis.yml: allow failure for unreliable hosts
  exec: flush the whole TLB if a watchpoint crosses a page boundary
  tests/plugin: correctly honour io_count
  scripts/clean-includes: Mark 'qemu/qemu-plugin.h' as special header
  qemu-plugin.h: add missing include <stddef.h> to define size_t

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 41 insertions, 16 deletions

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index aff98a0ede..e3e2181290 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -27,6 +27,7 @@
 #include "migration/blocker.h"
 #include "migration/qemu-file-types.h"
 #include "sysemu/dma.h"
+#include "sysemu/tcg.h"
 #include "trace.h"
 
 /* enabled until disconnected backend stabilizes */
@@ -403,26 +404,50 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
     return r;
 }
 
+/*
+ * vhost_section: identify sections needed for vhost access
+ *
+ * We only care about RAM sections here (where virtqueue and guest
+ * internals accessed by virtio might live). If we find one we still
+ * allow the backend to potentially filter it out of our list.
+ */
 static bool vhost_section(struct vhost_dev *dev, MemoryRegionSection *section)
 {
-    bool result;
-    bool log_dirty = memory_region_get_dirty_log_mask(section->mr) &
-                     ~(1 << DIRTY_MEMORY_MIGRATION);
-    result = memory_region_is_ram(section->mr) &&
-        !memory_region_is_rom(section->mr);
-
-    /* Vhost doesn't handle any block which is doing dirty-tracking other
-     * than migration; this typically fires on VGA areas.
-     */
-    result &= !log_dirty;
+    MemoryRegion *mr = section->mr;
+
+    if (memory_region_is_ram(mr) && !memory_region_is_rom(mr)) {
+        uint8_t dirty_mask = memory_region_get_dirty_log_mask(mr);
+        uint8_t handled_dirty;
+
+        /*
+         * Kernel based vhost doesn't handle any block which is doing
+         * dirty-tracking other than migration for which it has
+         * specific logging support. However for TCG the kernel never
+         * gets involved anyway so we can also ignore it's
+         * self-modiying code detection flags. However a vhost-user
+         * client could still confuse a TCG guest if it re-writes
+         * executable memory that has already been translated.
+         */
+        handled_dirty = (1 << DIRTY_MEMORY_MIGRATION) |
+            (1 << DIRTY_MEMORY_CODE);
 
-    if (result && dev->vhost_ops->vhost_backend_mem_section_filter) {
-        result &=
-            dev->vhost_ops->vhost_backend_mem_section_filter(dev, section);
-    }
+        if (dirty_mask & ~handled_dirty) {
+            trace_vhost_reject_section(mr->name, 1);
+            return false;
+        }
+
+        if (dev->vhost_ops->vhost_backend_mem_section_filter &&
+            !dev->vhost_ops->vhost_backend_mem_section_filter(dev, section)) {
+            trace_vhost_reject_section(mr->name, 2);
+            return false;
+        }
 
-    trace_vhost_section(section->mr->name, result);
-    return result;
+        trace_vhost_section(mr->name);
+        return true;
+    } else {
+        trace_vhost_reject_section(mr->name, 3);
+        return false;
+    }
 }
 
 static void vhost_begin(MemoryListener *listener)