Blame SOURCES/kvm-address_space_write-address_space_to_flatview-needs-.patch

37e7a1
From 2f3881255e6a50d9821f390972b07c1e9d9de626 Mon Sep 17 00:00:00 2001
37e7a1
From: Paolo Bonzini <pbonzini@redhat.com>
37e7a1
Date: Thu, 8 Mar 2018 15:58:15 +0100
37e7a1
Subject: [PATCH 02/17] address_space_write: address_space_to_flatview needs
37e7a1
 RCU lock
37e7a1
37e7a1
RH-Author: Paolo Bonzini <pbonzini@redhat.com>
37e7a1
Message-id: <20180308155819.20598-3-pbonzini@redhat.com>
37e7a1
Patchwork-id: 79191
37e7a1
O-Subject: [RHEL7.5 qemu-kvm-rhev PATCH 2/6] address_space_write: address_space_to_flatview needs RCU lock
37e7a1
Bugzilla: 1554930
37e7a1
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
37e7a1
RH-Acked-by: Thomas Huth <thuth@redhat.com>
37e7a1
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
37e7a1
37e7a1
address_space_write is calling address_space_to_flatview but it can
37e7a1
be called outside the RCU lock.  To fix it, push the rcu_read_lock/unlock
37e7a1
pair up from flatview_write to address_space_write.
37e7a1
37e7a1
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
37e7a1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
37e7a1
(cherry pick from commit 4c6ebbb364aa6f42c5d8e83e932e967eb83f0e44)
37e7a1
37e7a1
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
37e7a1
---
37e7a1
 exec.c | 37 ++++++++++++++++++++++---------------
37e7a1
 1 file changed, 22 insertions(+), 15 deletions(-)
37e7a1
37e7a1
diff --git a/exec.c b/exec.c
37e7a1
index 5a12e55..8b50133 100644
37e7a1
--- a/exec.c
37e7a1
+++ b/exec.c
37e7a1
@@ -2942,6 +2942,7 @@ static MemTxResult flatview_write_continue(FlatView *fv, hwaddr addr,
37e7a1
     return result;
37e7a1
 }
37e7a1
 
37e7a1
+/* Called from RCU critical section.  */
37e7a1
 static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
37e7a1
                                   const uint8_t *buf, int len)
37e7a1
 {
37e7a1
@@ -2950,25 +2951,14 @@ static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
37e7a1
     MemoryRegion *mr;
37e7a1
     MemTxResult result = MEMTX_OK;
37e7a1
 
37e7a1
-    if (len > 0) {
37e7a1
-        rcu_read_lock();
37e7a1
-        l = len;
37e7a1
-        mr = flatview_translate(fv, addr, &addr1, &l, true);
37e7a1
-        result = flatview_write_continue(fv, addr, attrs, buf, len,
37e7a1
-                                         addr1, l, mr);
37e7a1
-        rcu_read_unlock();
37e7a1
-    }
37e7a1
+    l = len;
37e7a1
+    mr = flatview_translate(fv, addr, &addr1, &l, true);
37e7a1
+    result = flatview_write_continue(fv, addr, attrs, buf, len,
37e7a1
+                                     addr1, l, mr);
37e7a1
 
37e7a1
     return result;
37e7a1
 }
37e7a1
 
37e7a1
-MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
37e7a1
-                                              MemTxAttrs attrs,
37e7a1
-                                              const uint8_t *buf, int len)
37e7a1
-{
37e7a1
-    return flatview_write(address_space_to_flatview(as), addr, attrs, buf, len);
37e7a1
-}
37e7a1
-
37e7a1
 /* Called within RCU critical section.  */
37e7a1
 MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr,
37e7a1
                                    MemTxAttrs attrs, uint8_t *buf,
37e7a1
@@ -3077,6 +3067,23 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr,
37e7a1
                        addr, attrs, buf, len, is_write);
37e7a1
 }
37e7a1
 
37e7a1
+MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
37e7a1
+                                MemTxAttrs attrs,
37e7a1
+                                const uint8_t *buf, int len)
37e7a1
+{
37e7a1
+    MemTxResult result = MEMTX_OK;
37e7a1
+    FlatView *fv;
37e7a1
+
37e7a1
+    if (len > 0) {
37e7a1
+        rcu_read_lock();
37e7a1
+        fv = address_space_to_flatview(as);
37e7a1
+        result = flatview_write(fv, addr, attrs, buf, len);
37e7a1
+        rcu_read_unlock();
37e7a1
+    }
37e7a1
+
37e7a1
+    return result;
37e7a1
+}
37e7a1
+
37e7a1
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
37e7a1
                             int len, int is_write)
37e7a1
 {
37e7a1
-- 
37e7a1
1.8.3.1
37e7a1