From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60389) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fzxaj-0003jq-M1 for qemu-devel@nongnu.org; Wed, 12 Sep 2018 01:21:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fzxXA-0007dg-Nn for qemu-devel@nongnu.org; Wed, 12 Sep 2018 01:17:52 -0400 Received: from mail-pg1-x541.google.com ([2607:f8b0:4864:20::541]:37806) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fzxXA-0007dU-HR for qemu-devel@nongnu.org; Wed, 12 Sep 2018 01:17:48 -0400 Received: by mail-pg1-x541.google.com with SMTP id 2-v6so414743pgo.4 for ; Tue, 11 Sep 2018 22:17:48 -0700 (PDT) From: Li Qiang Date: Tue, 11 Sep 2018 22:17:41 -0700 Message-Id: <1536729461-2692-1-git-send-email-liq3ea@gmail.com> Subject: [Qemu-devel] [PATCH] fw_cfg_mem: add read memory region callback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mst@redhat.com, ehabkost@redhat.com, lersek@redhat.com, peter.maydell@linaro.org, richard.henderson@linaro.org Cc: qemu-devel@nongnu.org, Li Qiang The write/read should be paired, this can avoid the NULL-deref while the guest reads the fw_cfg port. Signed-off-by: Li Qiang --- hw/nvram/fw_cfg.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index d79a568f54..6de7809f1a 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -434,6 +434,11 @@ static bool fw_cfg_data_mem_valid(void *opaque, hwaddr addr, return addr == 0; } +static uint64_t fw_cfg_ctl_mem_read(void *opaque, hwaddr addr, unsigned size) +{ + return 0; +} + static void fw_cfg_ctl_mem_write(void *opaque, hwaddr addr, uint64_t value, unsigned size) { @@ -468,6 +473,7 @@ static bool fw_cfg_comb_valid(void *opaque, hwaddr addr, } static const MemoryRegionOps fw_cfg_ctl_mem_ops = { + .read = fw_cfg_ctl_mem_read, .write = fw_cfg_ctl_mem_write, .endianness = DEVICE_BIG_ENDIAN, .valid.accepts = fw_cfg_ctl_mem_valid, -- 2.11.0