From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34799) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uzq7G-0003Aj-Ef for qemu-devel@nongnu.org; Thu, 18 Jul 2013 11:27:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uzq7B-0004on-Ad for qemu-devel@nongnu.org; Thu, 18 Jul 2013 11:27:38 -0400 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:56043) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uzq7A-0004nu-M2 for qemu-devel@nongnu.org; Thu, 18 Jul 2013 11:27:33 -0400 Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 18 Jul 2013 20:48:39 +0530 Message-ID: <51E80954.1030708@linux.vnet.ibm.com> Date: Thu, 18 Jul 2013 23:27:16 +0800 From: Mike Qiu MIME-Version: 1.0 References: <1373946643-10609-1-git-send-email-qiudayu@linux.vnet.ibm.com> In-Reply-To: <1373946643-10609-1-git-send-email-qiudayu@linux.vnet.ibm.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] Bug Fix:Segmentation fault when use usb-ehci device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aik@ozlabs.ru, Mike Qiu , qemu-ppc@nongnu.org, agraf@suse.de, xiaoguangrong@linux.vnet.ibm.com Hi all Any comments ? Thanks Mike 2013/7/16 11:50, Mike Qiu wrote: > For usb-ehci in qemu, its caps just has read() operation, > the write() operation does not exist. > > This cause a Segmentation fault when use usb-ehci device in ppc64 > platform. > > here is gdb output: > > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0x3fffa7fcef20 (LWP 6793)] > 0x00000000103f5244 in memory_region_oldmmio_write_accessor > (opaque=0x113e9e78, addr=9, value=0x3fffa7fce088, > size=1, shift=0, mask=255) at /home/Mike/qemu-impreza/memory.c:384 > 384 mr->ops->old_mmio.write[ctz32(size)](mr->opaque, addr, tmp); > (gdb) p *mr->ops > $1 = {read = @0x10716f68: 0x1020699c , write = 0, > endianness = DEVICE_LITTLE_ENDIAN, valid = {min_access_size = 1, > max_access_size = 4, unaligned = false, accepts = 0}, impl = > {min_access_size = 1, max_access_size = 1, unaligned = false}, > old_mmio = {read = {0, 0, 0}, write = {0, 0, 0}}} > > Becasue function write() of mr->ops has not been implement, in > function memory_region_dispatch_write(), it call > oldmmio write accessor, but at the same time old_mmio still not > been implement by default. > > That is the root cause of the Segmentation fault. > > To solve this problem, add empty function: ehci_caps_write() > > Signed-off-by: Mike Qiu > --- > hw/usb/hcd-ehci.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c > index 67e4b24..6c8a439 100644 > --- a/hw/usb/hcd-ehci.c > +++ b/hw/usb/hcd-ehci.c > @@ -1072,6 +1072,12 @@ static void ehci_port_write(void *ptr, hwaddr addr, > trace_usb_ehci_portsc_change(addr + s->portscbase, addr >> 2, *portsc, old); > } > > +static void ehci_caps_write(void *ptr, hwaddr addr, uint64_t val, > + unsigned size) > +{ > + /* nothing */ > +} > + > static void ehci_opreg_write(void *ptr, hwaddr addr, > uint64_t val, unsigned size) > { > @@ -2380,6 +2386,7 @@ static void ehci_frame_timer(void *opaque) > > static const MemoryRegionOps ehci_mmio_caps_ops = { > .read = ehci_caps_read, > + .write = ehci_caps_write, > .valid.min_access_size = 1, > .valid.max_access_size = 4, > .impl.min_access_size = 1,