Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2014-08-21 Thread Richard Yao
I use it all the time, but I have not updated to a more recent kernel yet. I am at LinuxCon, so I am unlikely to try it until I get home. > On Aug 21, 2014, at 2:50 PM, Christopher Covington > wrote: > > Hi Richard, > >> On 11/25/2013 10:49 AM, Richard Yao wrote: >> I booted a Gentoo Linux in

Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2014-08-21 Thread Christopher Covington
Hi Richard, On 11/25/2013 10:49 AM, Richard Yao wrote: > I booted a Gentoo Linux installation in QEMU with a 9P rootfs as follows: > > sudo qemu-kvm -cpu host -m 1024 -kernel > /mnt/test/usr/src/linux-3.13-rc1/arch/x86/boot/bzImage -append > 'root=/dev/root rootfstype=9p rootflags=trans=virtio,ve

Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2013-11-26 Thread Richard Yao
I have this bad habit of not reviewing emails until after I send them. Anyway, Chris, thanks for your offer of help, but I can handle this on my own. The previous email was mostly to give you an early version of the patch and let you know what I plan to do to improve upon it before I propose some v

Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2013-11-26 Thread Richard Yao
Christopher, It sounds like you disabled zero-copy entirely, which is not necessary. As far as I recall, loading kernel modules is the only case in which valloc() allocated buffers are used. In the worst case, we only need to disable zero-copy on such buffers. I have been using a small patch to do

Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2013-11-26 Thread Christopher Covington
Hi Richard, On 11/25/2013 04:50 PM, Richard Yao wrote: > I figured out the problem. There is zerocopy IO is being done via DMA to > a buffer allocated with valloc(). Right now, I am running a hack-fix > locally so I can get some other stuff done first. I will propose a > proper fix to the list in

Re: [Qemu-devel] QEMU dies on any attempt to load a Linux kernel module when using a 9P rootfs

2013-11-25 Thread Richard Yao
I figured out the problem. There is zerocopy IO is being done via DMA to a buffer allocated with valloc(). Right now, I am running a hack-fix locally so I can get some other stuff done first. I will propose a proper fix to the list in a few days. On 11/25/2013 10:49 AM, Richard Yao wrote: > I boot