OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-dev message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: RE: [Qemu-devel] [PATCH v9 00/12] virtio-crypto: introduce framework and device emulation

> From: Halil Pasic [mailto:pasic@linux.vnet.ibm.com]
> Sent: Monday, October 31, 2016 4:00 AM
> Subject: Re: [Qemu-devel] [PATCH v9 00/12] virtio-crypto: introduce framework
> and device emulation
> On 10/20/2016 01:45 PM, Gonglei wrote:
> > The front-end linux kernel driver (Experimental at present) is publicly
> accessible from:
> >
> >    https://github.com/gongleiarei/virtio-crypto-linux-driver.git
> Hi!
> I'm very interested in making sure this work for the s390x architecture
> too.  So to familiarize with the stuff I wanted to give it a spin on
> x86_64 and then transit to s390x and look for possible issues.

> Unfortunately I encountered a problem already on x86_64, more precisely
> the guest hangs in virtio_crypto_alg_ablkcipher_init_session after the
> kick. But before I start explaining in detail let me ask you: what are
> your plans for the linux kernel driver? I used the most current version
> from your github, but also tried to look for patches on mailing lists
> and I have found none. 

I haven't submit the virtio-crypto driver to the mailing list yet cause
I wanted to the patches on the QEMU side can be merged firstly,
and then focus to the frontend driver.

> IMHO the problem causing my hang is in the kernel
> module. But I do not know here am I supposed to comment on it -- so I'm
> commenting here. Furthermore your kernel module currently do not seem to
> care about endianness which is bad for s390x.
That's true.

> The hangs  basically boils down to the following: after the kick in
> virtio_crypto_alg_ablkcipher_init_session we reach the point (in QEMU)
> where we want to translate the address for the third descriptor, the one
> which designates a buffer for the virtio_crypto_session_input. My
> backtrace looks like this:
> #0  address_space_translate (as=<optimized out>,
> as@entry=0x55555607d700 <address_space_memory>,
> addr=addr@entry=71468256835928, xlat=xlat@entry=0x7fffef4dc1a0,
> plen=plen@entry=0x7fffef4dc198, is_write=is_write@entry=true)
>     at /home/pasic/devel/qemu/exec.c:481
> #1  0x000055555575ef19 in address_space_map (as=0x55555607d700
> <address_space_memory>, addr=71468256835928, plen=<optimized out>,
> is_write=<optimized out>) at /home/pasic/devel/qemu/exec.c:2927
> #2  0x00005555557e5d00 in virtqueue_map_desc (vdev=0x555557d80de0,
> p_num_sg=0x7fffef4dc2bc, addr=0x7fffef4dc2f0, iov=0x7fffef4de300,
> max_num_sg=1022, is_write=true, pa=71468256835928, sz=16)
>     at /home/pasic/devel/qemu/hw/virtio/virtio.c:558
> #3  0x00005555557e5f86 in virtqueue_pop (vq=0x7fffef4dc2c0,
> sz=93825003936576) at /home/pasic/devel/qemu/hw/virtio/virtio.c:717
> #4  0x00005555557ed80b in virtio_crypto_handle_ctrl (vdev=<optimized out>,
> vq=0x7fffeec3e090) at /home/pasic/devel/qemu/hw/virtio/virtio-crypto.c:218
> Now the first suspicious thing I see is that address_space_translate
> returns a pointer to the memory region io_mem_unassigned. Next thing
> happening is that we take the !memory_access_is_direct(mr, is_write)
> branch in address_space_map and return NULL at line 2932 which however
> makes  virtqueue_map_desc report "qemu-system-x86_64: virtio: bogus
> descriptor or out of resources" and return with false. Then pop returns
> null too and spins virtio_crypto_alg_ablkcipher_init_session till the
> end of time waiting for the answer.
It seems that the frontend driver passed a invalid gpa to the QEMU side,
The Qemu side will invokes virtio_error() to notify the guest to reset the

> Now if I change the code so that the virtio_crypto_session_input
> instance's backing memory is allocated with  kzalloc(sizeof(*input),
> GFP_DMA|GFP_NOIO) of allocating the on the stack things start working
> for me. I'm not too deep into this yet, so please forgive me if
> I'm a bit vague.
Good, maybe you find a bug of the frontend driver. Using stack memory
might not be a good idea ;)

> I was testing with tcrypt mode=500 instead of cryptodev-linux but I
> guess that should be irrelevant.
I think so as well.

> Looking forward to your answer.
> Halil


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]