Re: Broken pci_block_user_cfg_access interface

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-08-29 17:58, Michael S. Tsirkin wrote:
> On Mon, Aug 29, 2011 at 05:42:16PM +0200, Jan Kiszka wrote:
>> I still don't get what prevents converting ipr to allow plain mutex
>> synchronization. My vision is:
>>  - push reset-on-error of ipr into workqueue (or threaded IRQ?)
>>  - require mutex synchronization for common config space access
> 
> Meaning pci_user_ read/write config?

And pci_dev_reset, yes.

> 
>>     and the
>>    full reset cycle
>>  - only exception: INTx status/masking access
>>     => use pci_lock + test for reset_in_progress, skip operation if
>>        that is the case
>>
>> That would allow to drop the whole block_user_cfg infrastructure.
>>
>> Jan
> 
> We still need to block userspace access while INTx does
> the status/masking access, right?

Yes, pci_lock would do that for us.

We should consider making the related bits for INTx test & mask/unmask
generic PCI services so that no user (uio_pci_generic, kvm, vfio) needs
to worry about the locking details.

Jan

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