hw/intc/arm_gicv3_its: Don't use data if reading command failed

In process_cmdq(), we read 64 bits of the command packet, which
contain the command identifier, which we then switch() on to dispatch
to an appropriate sub-function.  However, if address_space_ldq_le()
reports a memory transaction failure, we still read the command
identifier out of the data and switch() on it.  Restructure the code
so that we stop immediately (stalling the command queue) in this
case.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220111171048.3545974-5-peter.maydell@linaro.org

diff --git a/hw/intc/arm_gicv3_its.c b/hw/intc/arm_gicv3_its.c
index a6c2299a091f555dbaf361ace0cfbdec3aaaf628..c1f76682d04531c4f1c2e7e5064fc482cf3af669 100644 (file)
--- a/hw/intc/arm_gicv3_its.c
+++ b/hw/intc/arm_gicv3_its.c
@@ -672,8 +672,13 @@ static void process_cmdq(GICv3ITSState *s)
         data = address_space_ldq_le(as, s->cq.base_addr + cq_offset,
                                     MEMTXATTRS_UNSPECIFIED, &res);
         if (res != MEMTX_OK) {
-            result = false;
+            s->creadr = FIELD_DP64(s->creadr, GITS_CREADR, STALLED, 1);
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: could not read command at 0x%" PRIx64 "\n",
+                          __func__, s->cq.base_addr + cq_offset);
+            break;
         }
+
         cmd = (data & CMD_MASK);
 
         switch (cmd) {