From patchwork Mon Oct 19 12:30:53 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin O'Connor X-Patchwork-Id: 532284 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id BA56B1401F6 for ; Mon, 19 Oct 2015 23:32:02 +1100 (AEDT) Received: from localhost ([::1]:39173 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zo9bc-00064I-Jq for incoming@patchwork.ozlabs.org; Mon, 19 Oct 2015 08:32:00 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37636) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zo9b0-0005ee-EY for qemu-devel@nongnu.org; Mon, 19 Oct 2015 08:31:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zo9au-0003xY-8F for qemu-devel@nongnu.org; Mon, 19 Oct 2015 08:31:22 -0400 Received: from mail-qg0-f42.google.com ([209.85.192.42]:34837) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zo9au-0003xM-5Y for qemu-devel@nongnu.org; Mon, 19 Oct 2015 08:31:16 -0400 Received: by qgbb65 with SMTP id b65so49950647qgb.2 for ; Mon, 19 Oct 2015 05:31:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=smIolEfBbCB2b62okqEpVkjWaGWtB0U8mFAn7eQi7tg=; b=SmYYM6GZISHQd1S4LDEH/Di6oaa5tCoyZPhaI+skR1I8oqpRrCEuJ2+/SQ+7Xmlhh5 v0mrV2KK88WAboqC7xcsdu3DspczloEjNm2ZqY67k7/FSB8AL/iRz904/yUvSr3W6cQ2 Iks/U0+6IgNjd6aU9/QUHgqR5TeUccpeOB/+v3zFQ7q14FIuPPRj2VuuATr8xxsoXjJ5 jDCz+i2fAWZBSUVcp/6e3GFjw++9QJtGjGOO//e9kawo+VKebX3KuQmxjzmOWkelo064 nUGfcEa46kRbqID/GKYUeWREw8N+TJZojSu097sSiYF6udnqWOnZDsxBT/SDREbInmwm 2fvw== X-Gm-Message-State: ALoCoQn9aPHHS4RmxlBDovhJzB6seVq+Acnc7/9EfORowxdhCnLDMFUbh+zCE04sMqv7X6G5n1Q3 X-Received: by 10.140.40.239 with SMTP id x102mr14651570qgx.10.1445257875795; Mon, 19 Oct 2015 05:31:15 -0700 (PDT) Received: from localhost (209-122-232-221.c3-0.avec-ubr1.nyr-avec.ny.cable.rcn.com. [209.122.232.221]) by smtp.gmail.com with ESMTPSA id u3sm14246197qki.22.2015.10.19.05.31.14 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Oct 2015 05:31:15 -0700 (PDT) From: Kevin O'Connor To: qemu-devel@nongnu.org, =?UTF-8?q?Marc=20Mar=C3=AD?= , Gerd Hoffmann Date: Mon, 19 Oct 2015 08:30:53 -0400 Message-Id: <1445257853-16148-1-git-send-email-kevin@koconnor.net> X-Mailer: git-send-email 2.4.3 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.192.42 Cc: Peter Maydell , Laszlo Ersek , Stefan Hajnoczi Subject: [Qemu-devel] [PATCHv3] fw_cfg: Define a static signature to be returned on DMA port reads X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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 --- Gerd/Marc - if you respin the fw_cfg series, I believe this patch will avoid the Windows compile error. Changes since v2: - use /* */ comments instead of C++ comments - Use ULL on 64bit constants Changes since v1: - use extract64() - reword documentation to be more clear --- 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,