From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55415) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUeDl-0000ce-3z for qemu-devel@nongnu.org; Thu, 18 Sep 2014 12:06:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XUeDa-0002Qm-C0 for qemu-devel@nongnu.org; Thu, 18 Sep 2014 12:06:13 -0400 From: Paolo Bonzini Date: Thu, 18 Sep 2014 18:05:46 +0200 Message-Id: <1411056346-22538-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH for-2.1.2] pc: add more padding between the end of the initrd and the end of memory List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, jsnow@redhat.com, mdroth@linux.vnet.ibm.com, mst@redhat.com Besides ACPI tables, there are a few other uses of high memory in SeaBIOS: SMBIOS tables and USB drivers use it in particular. These uses allocate a very small amount of memory. Malloc metadata also lives there. So we need _some_ extra padding there to avoid initrd breakage, but not much. John Snow found a case where RHEL5 was broken by the recent change to ACPI_TABLE_SIZE; in his case 4KB of extra padding are fine, but just to be safe I am adding 32KB, which is roughly the same amount of padding that was left by QEMU 2.0 and earlier. Signed-off-by: Paolo Bonzini --- hw/i386/pc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 77b6782..b9d4be7 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -73,7 +73,7 @@ #endif /* Leave a chunk of memory at the top of RAM for the BIOS ACPI tables. */ -unsigned acpi_data_size = 0x20000; +unsigned acpi_data_size = 0x28000; void pc_set_legacy_acpi_data_size(void) { acpi_data_size = 0x10000; -- 1.8.3.1