From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53310) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8ytX-0006nu-W7 for qemu-devel@nongnu.org; Mon, 12 Aug 2013 16:39:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8ytS-0007m4-LI for qemu-devel@nongnu.org; Mon, 12 Aug 2013 16:39:15 -0400 Received: from v220110690675601.yourvserver.net ([78.47.199.172]:45749) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8ytS-0007ln-An for qemu-devel@nongnu.org; Mon, 12 Aug 2013 16:39:10 -0400 Message-ID: <520947DE.9080306@weilnetz.de> Date: Mon, 12 Aug 2013 22:38:54 +0200 From: Stefan Weil MIME-Version: 1.0 References: <1376336660-11927-1-git-send-email-aurelien@aurel32.net> In-Reply-To: <1376336660-11927-1-git-send-email-aurelien@aurel32.net> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-1.6] mips_malta: do not raise exceptions when accessing invalid memory List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: qemu-devel@nongnu.org, =?ISO-8859-15?Q?Andreas_F=E4rber?= , Peter Jovanovic Am 12.08.2013 21:44, schrieb Aurelien Jarno: > Since commit c658b94f6e8c206c59d02aa6fbac285b86b53d2c, MIPS raises > exceptions when accessing invalid memory. This is not the correct > behaviour for MIPS Malta Core LV, as the GT-64120A system controller > just ignore undecoded access. This feature is used by the Linux kernel > to probe for some devices. > > Emulate the correct behaviour in QEMU by adding an empty slot covering > the entire memory space decoded by the GT-64120A. > > Signed-off-by: Aurelien Jarno > --- > default-configs/mips-softmmu.mak | 1 + > default-configs/mips64-softmmu.mak | 1 + > default-configs/mips64el-softmmu.mak | 1 + > default-configs/mipsel-softmmu.mak | 1 + > hw/mips/mips_malta.c | 6 ++++++ > 5 files changed, 10 insertions(+) > > diff --git a/default-configs/mips-softmmu.mak b/default-configs/mips-softmmu.mak > index 926709a..71177ef 100644 > --- a/default-configs/mips-softmmu.mak > +++ b/default-configs/mips-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mips64-softmmu.mak b/default-configs/mips64-softmmu.mak > index 0ef3f09..617301b 100644 > --- a/default-configs/mips64-softmmu.mak > +++ b/default-configs/mips64-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mips64el-softmmu.mak b/default-configs/mips64el-softmmu.mak > index 6089318..317b151 100644 > --- a/default-configs/mips64el-softmmu.mak > +++ b/default-configs/mips64el-softmmu.mak > @@ -36,3 +36,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/default-configs/mipsel-softmmu.mak b/default-configs/mipsel-softmmu.mak > index cd59e24..532a9ae 100644 > --- a/default-configs/mipsel-softmmu.mak > +++ b/default-configs/mipsel-softmmu.mak > @@ -34,3 +34,4 @@ CONFIG_JAZZ_LED=y > CONFIG_MC146818RTC=y > CONFIG_VT82C686=y > CONFIG_ISA_TESTDEV=y > +CONFIG_EMPTY_SLOT=y > diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c > index 0f5de33..61cb3e4 100644 > --- a/hw/mips/mips_malta.c > +++ b/hw/mips/mips_malta.c > @@ -50,6 +50,7 @@ > #include "qemu/host-utils.h" > #include "sysemu/qtest.h" > #include "qemu/error-report.h" > +#include "hw/empty_slot.h" > > //#define DEBUG_BOARD_INIT > > @@ -908,6 +909,11 @@ void mips_malta_init(QEMUMachineInitArgs *args) > DeviceState *dev = qdev_create(NULL, TYPE_MIPS_MALTA); > MaltaState *s = MIPS_MALTA(dev); > > + /* The whole address space decoded by the GT-64120A doesn't generate > + exception when accessing invalid memory. Create an empty slot to > + emulate this feature. */ > + empty_slot_init(0, 0x1fffffff); > + > qdev_init_nofail(dev); > > /* Make sure the first 3 serial ports are associated with a device. */ Hello Aurelien, the patch fixes Linux boot with Malta, therefore Tested-by: Stefan Weil The 2nd parameter of empty_slot_init is not the end address but the length, so I think it should be 0x20000000. With this modification, the patch is good for 1.6. I did not find a hint in the GT-64120A documentation about handling of addresses without connected devices. It is still strange that the exception handler throws a secondary exception with the current code. Regards, Stefan