From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45647) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZhcnY-0000tV-DG for qemu-devel@nongnu.org; Thu, 01 Oct 2015 08:17:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZhcnT-0003a0-KO for qemu-devel@nongnu.org; Thu, 01 Oct 2015 08:17:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49859) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZhcnT-0003Zo-EG for qemu-devel@nongnu.org; Thu, 01 Oct 2015 08:17:15 -0400 From: =?UTF-8?q?Marc=20Mar=C3=AD?= Date: Thu, 1 Oct 2015 14:16:59 +0200 Message-Id: <1443701819-13855-8-git-send-email-markmb@redhat.com> In-Reply-To: <1443701819-13855-1-git-send-email-markmb@redhat.com> References: <1443701677-13629-1-git-send-email-markmb@redhat.com> <1443701819-13855-1-git-send-email-markmb@redhat.com> Subject: [Qemu-devel] [PATCH v4 7/7] fw_cfg: Define a static signature to be returned on DMA port reads List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Drew , Stefan Hajnoczi , "Gabriel L. Somlo" , Kevin O'Connor , Gerd Hoffmann , Laszlo From: Kevin O'Connor Return a static signature ("QEMU CFG") if the guest does a read to the DMA address io register. Signed-off-by: Kevin O'Connor --- docs/specs/fw_cfg.txt | 4 ++++ hw/nvram/fw_cfg.c | 13 +++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 2d6b2da..249b99e 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -93,6 +93,10 @@ by selecting the "signature" item using key 0x0000 (FW_CFG_SIGNATURE), and reading four bytes from the data register. If the fw_cfg device is present, the four bytes read will contain the characters "QEMU". +Additionaly, if the DMA interface is available then a read to the DMA +Address will return 0x51454d5520434647 ("QEMU CFG" in big-endian +format). + === Revision / feature bitmap (Key 0x0001, FW_CFG_ID) === A 32-bit little-endian unsigned int, this item is used to check for enabled diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 59933b3..c6dcce4 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -53,6 +53,8 @@ #define FW_CFG_DMA_CTL_SKIP 0x04 #define FW_CFG_DMA_CTL_SELECT 0x08 +#define FW_CFG_DMA_SIGNATURE 0x51454d5520434647 /* "QEMU CFG" */ + typedef struct FWCfgEntry { uint32_t len; uint8_t *data; @@ -393,6 +395,12 @@ static void fw_cfg_dma_transfer(FWCfgState *s) trace_fw_cfg_read(s, 0); } +static uint64_t fw_cfg_dma_mem_read(void *opaque, hwaddr addr, + unsigned size) +{ + return FW_CFG_DMA_SIGNATURE >> ((8 - addr - size) * 8); +} + static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr, uint64_t value, unsigned size) { @@ -416,8 +424,8 @@ static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr, static bool fw_cfg_dma_mem_valid(void *opaque, hwaddr addr, unsigned size, bool is_write) { - return is_write && ((size == 4 && (addr == 0 || addr == 4)) || - (size == 8 && addr == 0)); + return !is_write || ((size == 4 && (addr == 0 || addr == 4)) || + (size == 8 && addr == 0)); } static bool fw_cfg_data_mem_valid(void *opaque, hwaddr addr, @@ -488,6 +496,7 @@ static const MemoryRegionOps fw_cfg_comb_mem_ops = { }; static const MemoryRegionOps fw_cfg_dma_mem_ops = { + .read = fw_cfg_dma_mem_read, .write = fw_cfg_dma_mem_write, .endianness = DEVICE_BIG_ENDIAN, .valid.accepts = fw_cfg_dma_mem_valid, -- 2.4.3