[PATCH v1 3/3] ARM: GICv3 ITS: flush all buffers, not just command queue

[Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>]

ITS manages Device Tables and Interrupt Translation Tables on its own,
so generally we are not interested which shareability and cacheability
attributes it uses. But there is one exception: ITS requires that DT
and ITT must be initialized with zeroes. If ITS belongs to the Inner
Cacheability domain there is no problem at all.

But in all other cases we need to do clean CPU caches manually, or
otherwise CPU can overwrite DT and ITT entries. From user perspective
this looks like interrupts are not delivered from a device.

Also, we will rename HOST_ITS_FLUSH_CMD_QUEUE flag to
HOST_ITS_FLUSH_BUFFERS because now this flag controls not only command
queue.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
---
 xen/arch/arm/gic-v3-its.c             | 7 +++++--
 xen/arch/arm/include/asm/gic_v3_its.h | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index 72cf318810..63e28a7706 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -107,7 +107,7 @@ static int its_send_command(struct host_its *hw_its, const 
void *its_cmd)
     }
 
     memcpy(hw_its->cmd_buf + writep, its_cmd, ITS_CMD_SIZE);
-    if ( hw_its->flags & HOST_ITS_FLUSH_CMD_QUEUE )
+    if ( hw_its->flags & HOST_ITS_FLUSH_BUFFERS )
         clean_dcache_va_range(hw_its->cmd_buf + writep, ITS_CMD_SIZE);
     else
         dsb(ishst);
@@ -335,7 +335,7 @@ static void *its_map_cbaser(struct host_its *its)
      */
     if ( !(reg & GITS_BASER_INNER_CACHEABILITY_MASK) )
     {
-        its->flags |= HOST_ITS_FLUSH_CMD_QUEUE;
+        its->flags |= HOST_ITS_FLUSH_BUFFERS;
         printk(XENLOG_WARNING "using non-cacheable ITS command queue\n");
     }
 
@@ -699,6 +699,9 @@ int gicv3_its_map_guest_device(struct domain *d,
     if ( !itt_addr )
         goto out_unlock;
 
+    if ( hw_its->flags & HOST_ITS_FLUSH_BUFFERS )
+        clean_dcache_va_range(itt_addr, nr_events * hw_its->itte_size);
+
     dev = xzalloc(struct its_device);
     if ( !dev )
         goto out_unlock;
diff --git a/xen/arch/arm/include/asm/gic_v3_its.h 
b/xen/arch/arm/include/asm/gic_v3_its.h
index c24d4752d0..460b008db5 100644
--- a/xen/arch/arm/include/asm/gic_v3_its.h
+++ b/xen/arch/arm/include/asm/gic_v3_its.h
@@ -107,7 +107,7 @@
 #include <xen/device_tree.h>
 #include <xen/rbtree.h>
 
-#define HOST_ITS_FLUSH_CMD_QUEUE        (1U << 0)
+#define HOST_ITS_FLUSH_BUFFERS          (1U << 0)
 #define HOST_ITS_USES_PTA               (1U << 1)
 
 /* We allocate LPIs on the hosts in chunks of 32 to reduce handling overhead. 
*/
-- 
2.42.0