From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51197) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUff3-0001EZ-GR for qemu-devel@nongnu.org; Thu, 18 Sep 2014 13:38:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XUfew-0002oG-HM for qemu-devel@nongnu.org; Thu, 18 Sep 2014 13:38:29 -0400 Date: Thu, 18 Sep 2014 20:41:34 +0300 From: "Michael S. Tsirkin" Message-ID: <20140918174134.GA27528@redhat.com> References: <1411056346-22538-1-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1411056346-22538-1-git-send-email-pbonzini@redhat.com> Subject: Re: [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: Paolo Bonzini Cc: qemu-stable@nongnu.org, jsnow@redhat.com, qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com On Thu, Sep 18, 2014 at 06:05:46PM +0200, Paolo Bonzini wrote: > 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 I already queued a patch with some slightly better comments so I'll keep that. Will append your text to the commit log. Thanks! > --- > 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