On Mon, Aug 29, 2011 at 06:14:39PM +0200, Jan Kiszka wrote:

On 2011-08-29 17:58, Michael S. Tsirkin wrote:

quoted

On Mon, Aug 29, 2011 at 05:42:16PM +0200, Jan Kiszka wrote:

quoted

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.

quoted

quoted

    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.

Well this means block_user_cfg is not going away,
this is what it really is: pci_lock + a bit to lock out userspace.

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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