[PATCH V2 02/22] qemu_ram_volatile

From: Steve Sistare <steven.sistare@oracle.com>
To: qemu-devel@nongnu.org
Cc: "Daniel P. Berrange" <berrange@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Jason Zeng" <jason.zeng@linux.intel.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Juan Quintela" <quintela@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Steve Sistare" <steven.sistare@oracle.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: [PATCH V2 02/22] qemu_ram_volatile
Date: Tue,  5 Jan 2021 07:41:50 -0800	[thread overview]
Message-ID: <1609861330-129855-3-git-send-email-steven.sistare@oracle.com> (raw)
In-Reply-To: <1609861330-129855-1-git-send-email-steven.sistare@oracle.com>

Add a function that returns true if any ram_list block represents
volatile memory.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 exec.c                | 30 ++++++++++++++++++++++++++++++
 include/exec/memory.h |  8 ++++++++
 slirp                 |  2 +-
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/exec.c b/exec.c
index 6f381f9..d1f31b4 100644
--- a/exec.c
+++ b/exec.c
@@ -2726,6 +2726,36 @@ ram_addr_t qemu_ram_addr_from_host(void *ptr)
     return block->offset + offset;
 }
 
+/*
+ * Return true if any memory regions are writable and not backed by shared
+ * memory.
+ */
+bool qemu_ram_volatile(Error **errp)
+{
+    RAMBlock *block;
+    MemoryRegion *mr;
+    bool ret = false;
+
+    rcu_read_lock();
+    QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+        mr = block->mr;
+        if (mr &&
+            memory_region_is_ram(mr) &&
+            !memory_region_is_ram_device(mr) &&
+            !memory_region_is_rom(mr) &&
+            (block->fd == -1 || !qemu_ram_is_shared(block))) {
+
+            error_setg(errp, "Memory region %s is volatile",
+                       memory_region_name(mr));
+            ret = true;
+            break;
+        }
+    }
+
+    rcu_read_unlock();
+    return ret;
+}
+
 /* Generate a debug exception if a watchpoint has been hit.  */
 void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
                           MemTxAttrs attrs, int flags, uintptr_t ra)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 8dba065..6115a01 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2522,6 +2522,14 @@ bool ram_block_discard_is_disabled(void);
  */
 bool ram_block_discard_is_required(void);
 
+/**
+ * qemu_ram_volatile: return true if any memory regions are writable and not
+ * backed by shared memory.
+ *
+ * @errp: returned error message identifying the bad region.
+ */
+bool qemu_ram_volatile(Error **errp);
+
 #endif
 
 #endif
diff --git a/slirp b/slirp
index ce94eba..a62d367 160000
--- a/slirp
+++ b/slirp
@@ -1 +1 @@
-Subproject commit ce94eba2042d52a0ba3d9e252ebce86715e94275
+Subproject commit a62d36734ffe9828d0f70df1b3898a3b4fbda755
-- 
1.8.3.1


