hw/intc/arm_gicv3: Make reserved register addresses RAZ/WI

The GICv3 specification says that reserved register addresses
should RAZ/WI. This means we need to return MEMTX_OK, not MEMTX_ERROR,
because now that we support generating external aborts the
latter will cause an abort on new board models.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1513183941-24300-2-git-send-email-peter.maydell@linaro.org
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/hw/intc/arm_gicv3_redist.c b/hw/intc/arm_gicv3_redist.c
index 77e5cfa327..8a8684d76e 100644
--- a/hw/intc/arm_gicv3_redist.c
+++ b/hw/intc/arm_gicv3_redist.c
@@ -455,6 +455,13 @@ MemTxResult gicv3_redist_read(void *opaque, hwaddr offset, uint64_t *data,
                       "size %u\n", __func__, offset, size);
         trace_gicv3_redist_badread(gicv3_redist_affid(cs), offset,
                                    size, attrs.secure);
+        /* The spec requires that reserved registers are RAZ/WI;
+         * so use MEMTX_ERROR returns from leaf functions as a way to
+         * trigger the guest-error logging but don't return it to
+         * the caller, or we'll cause a spurious guest data abort.
+         */
+        r = MEMTX_OK;
+        *data = 0;
     } else {
         trace_gicv3_redist_read(gicv3_redist_affid(cs), offset, *data,
                                 size, attrs.secure);
@@ -505,6 +512,12 @@ MemTxResult gicv3_redist_write(void *opaque, hwaddr offset, uint64_t data,
                       "size %u\n", __func__, offset, size);
         trace_gicv3_redist_badwrite(gicv3_redist_affid(cs), offset, data,
                                     size, attrs.secure);
+        /* The spec requires that reserved registers are RAZ/WI;
+         * so use MEMTX_ERROR returns from leaf functions as a way to
+         * trigger the guest-error logging but don't return it to
+         * the caller, or we'll cause a spurious guest data abort.
+         */
+        r = MEMTX_OK;
     } else {
         trace_gicv3_redist_write(gicv3_redist_affid(cs), offset, data,
                                  size, attrs.secure);