On Tue, Sep 29, 2020 at 06:30:20PM +0200, Greg Kurz wrote:
> This series addresses some misuse around vring addresses provided by
> userspace when using an IOTLB device. The misuse cause failures of
> the VHOST_SET_VRING_ADDR ioctl on POWER, which in turn causes QEMU
> to crash at migration time.
>
> While digging some more I realized that log_access_ok() can also be
> passed a GIOVA (vq->log_addr) even though log_used() will never log
> anything at that address. I could observe addresses beyond the end
> of the log bitmap being passed to access_ok(), but it didn't have any
> impact because the addresses were still acceptable from an access_ok()
> standpoint. Adding a second patch to fix that anyway.
>
> Note that I've also posted a patch for QEMU so that it skips the used
> structure GIOVA when allocating the log bitmap. Otherwise QEMU fails to
> allocate it because POWER puts GIOVAs very high in the address space (ie.
> over 0x800000000000000ULL).
>
> https://patchwork.ozlabs.org/project/qemu-devel/patch/160105498386.68108.2145229309875282336.stgit@bahia.lan/
I queued this. Jason, can you ack please?
> v2:
> - patch 1: move the (vq->ioltb) check from vhost_vq_access_ok() to
> vq_access_ok() as suggested by MST
> - patch 2: new patch
>
> ---
>
> Greg Kurz (2):
> vhost: Don't call access_ok() when using IOTLB
> vhost: Don't call log_access_ok() when using IOTLB
>
>
> drivers/vhost/vhost.c | 32 ++++++++++++++++++++++++--------
> 1 file changed, 24 insertions(+), 8 deletions(-)
>
> --
> Greg