From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60644) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gUjIN-00058n-W2 for qemu-devel@nongnu.org; Wed, 05 Dec 2018 21:21:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gUjIJ-0008SI-IM for qemu-devel@nongnu.org; Wed, 05 Dec 2018 21:21:43 -0500 Received: from mga04.intel.com ([192.55.52.120]:31853) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gUjIJ-0008Et-7O for qemu-devel@nongnu.org; Wed, 05 Dec 2018 21:21:39 -0500 From: Li Zhijian Date: Thu, 6 Dec 2018 10:32:13 +0800 Message-Id: <1544063533-10139-5-git-send-email-lizhijian@cn.fujitsu.com> In-Reply-To: <1544063533-10139-1-git-send-email-lizhijian@cn.fujitsu.com> References: <1544063533-10139-1-git-send-email-lizhijian@cn.fujitsu.com> Subject: [Qemu-devel] [PATCH for-4.0 v4 4/4] i386: allow to load initrd below 4G for recent linux List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, mst@redhat.com, peter.maydell@linaro.org Cc: philip.li@intel.com, zhijianx.li@intel.com, philmd@redhat.com, Li Zhijian , Paolo Bonzini , Richard Henderson , Eduardo Habkost , Marcel Apfelbaum a new field xloadflags was added to recent x86 linux, and BIT 1: XLF_CAN_BE_LOADED_ABOVE_4G is used to tell bootload that where initrd can be loaded safely. Current QEMU/BIOS always loads initrd below below_4g_mem_size which is always less than 4G, so here limiting initrd_max to 4G - 1 simply is enough if this bit is set. CC: Paolo Bonzini CC: Richard Henderson CC: Eduardo Habkost CC: "Michael S. Tsirkin" CC: Marcel Apfelbaum Signed-off-by: Li Zhijian --- V3: correct grammar and check XLF_CAN_BE_LOADED_ABOVE_4G first (Michael S. Tsirkin) Signed-off-by: Li Zhijian --- hw/i386/pc.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 3b10726..baa99c0 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -904,7 +904,15 @@ static void load_linux(PCMachineState *pcms, #endif /* highest address for loading the initrd */ - if (protocol >= 0x203) { + if (protocol >= 0x20c && + lduw_p(header+0x236) & XLF_CAN_BE_LOADED_ABOVE_4G) { + /* + * Although kernel allows initrd loading to above 4G, + * it just makes it as large as possible while still staying below 4G + * since current BIOS always loads initrd below pcms->below_4g_mem_size + */ + initrd_max = UINT32_MAX; + } else if (protocol >= 0x203) { initrd_max = ldl_p(header+0x22c); } else { initrd_max = 0x37ffffff; -- 2.7.4