From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50001) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoQ9C-0003Ax-4q for qemu-devel@nongnu.org; Tue, 20 Oct 2015 02:11:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZoQ9A-0003KW-NH for qemu-devel@nongnu.org; Tue, 20 Oct 2015 02:11:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35177) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoQ9A-0003Jn-Ik for qemu-devel@nongnu.org; Tue, 20 Oct 2015 02:11:44 -0400 From: Gerd Hoffmann Date: Tue, 20 Oct 2015 08:11:32 +0200 Message-Id: <1445321492-2902-8-git-send-email-kraxel@redhat.com> In-Reply-To: <1445321492-2902-1-git-send-email-kraxel@redhat.com> References: <1445321492-2902-1-git-send-email-kraxel@redhat.com> Subject: [Qemu-devel] [PULL v2 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: Kevin O'Connor , Gerd Hoffmann 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 Reviewed-by: Laszlo Ersek Reviewed-by: Stefan Hajnoczi Signed-off-by: Gerd Hoffmann --- docs/specs/fw_cfg.txt | 3 +++ hw/nvram/fw_cfg.c | 14 ++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 536909a..b8c794f 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -93,6 +93,9 @@ 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". +If the DMA interface is available, then reading the DMA Address +Register returns 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 91829d4..73b0a81 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 0x51454d5520434647ULL /* "QEMU CFG" */ + typedef struct FWCfgEntry { uint32_t len; uint8_t *data; @@ -397,6 +399,13 @@ 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 a signature value (and handle various read sizes) */ + return extract64(FW_CFG_DMA_SIGNATURE, (8 - addr - size) * 8, size * 8); +} + static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr, uint64_t value, unsigned size) { @@ -420,8 +429,8 @@ 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, @@ -492,6 +501,7 @@ 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, -- 1.8.3.1