Re: [RFC v2 0/1] memory: Delete assertion in memory_region_unregister_iommu_notifier

[Paolo Bonzini]

On 26/06/20 08:41, Eugenio Pérez wrote:
> If we examinate *entry in frame 4 of backtrace:
> *entry = {target_as = 0x555556f6c050, iova = 0x0, translated_addr = 0x0,
> addr_mask = 0xffffffffffffffff, perm = 0x0}
> 
> Which (I think) tries to invalidate all the TLB registers of the device.
> 
> Just deleting that assert is enough for the VM to start and communicate
> using IOMMU, but maybe a better alternative is possible. We could move
> it to the caller functions in other cases than IOMMU invalidation, or
> make it conditional only if not invalidating.

Yes, I think moving it up in the call stack is better.  I cannot say
where because the backtrace was destroyed by git (due to lines starting
with "#").

Paolo

> Any comment would be appreciated. Thanks!
> 
> Guest kernel version: kernel-3.10.0-1151.el7.x86_64
> 
> Bug reference: https://bugs.launchpad.net/qemu/+bug/1885175
> 
> v2: Actually delete assertion instead of just commenting out using C99
> 
> Eugenio Pérez (1):
>   memory: Delete assertion in memory_region_unregister_iommu_notifier
> 
>  memory.c | 2 --
>  1 file changed, 2 deletions(-)
>