Re: [Xen-devel] [PATCH] Fixfor xen bug 1306: Dom0 hangs when destoryingone guest with MSI NIC assigned

[Espen Skoglund <espen.skoglund@xxxxxxxxxxxxx>]

Sorry for non-responsiveness (holidays, off-line).

You're absolutely right on these problems.  Screwup on my part.
\me feels reeally stupid now.

        eSk



[Haitao Shan]
> Hi, Keir,
> Since I have got no response from Espen, I try to fix the bug
> myself. Please see the attached patch.  Description: This patch will
> fix bug 1306. The reason is explained in my former mail. This patch
> also removes hard tabs in msi.c.

> Signed-off-by: Shan Haitao <Haitao.shan@xxxxxxxxx>

> Best Regards
> Shan Haitao

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Shan, Haitao
> Sent: 2008$BG/(J7$B7n(J29$BF|(J 15:22
> To: Espen Skoglund; Keir Fraser
> Cc: Jiang, Yunhong; xen-devel@xxxxxxxxxxxxxxxxxxx; Li, Xin B; Li, Susie
> Subject: [Xen-devel] Root cause of xen bug 1306: Dom0 hangs when 
> destoryingone guest with MSI NIC assigned

> Hi, Espen,

> Some recent changsets break the MSI function. Please see my comments embedded 
> in the following code snippet.
> Another problem is the following function is invoked by pci_release_devices, 
> which is executed before iommu_domain_destroy. However, the following 
> function must be executed after unbinding all guest pirqs. The unbinding code 
> is located in iommu_domain_destroy.

> I am not familiar with recent IOMMU code. Could you please have a look?

> static void msi_free_vectors(struct pci_dev* dev)
> {
>     struct msi_desc *entry, *tmp;
>     irq_desc_t *desc;
>     unsigned long flags;

> retry:
>     list_for_each_entry_safe( entry, tmp, &dev->msi_list, list )
>     {
>         desc = &irq_desc[entry->vector];

>     local_irq_save(flags);
>     if ( !spin_trylock(&desc->lock) )
>     {
>         local_irq_restore(flags);
>         goto retry;
>     }

>         spin_lock_irqsave(&desc->lock, flags);
> -----$B"*(Jthe above line should be removed, otherwise dead lock will occur 
> by acquiring a lock already acquired.
>         if ( desc->handler == &pci_msi_type )
>         {
>             /* MSI is not shared, so should be released already */
>             BUG_ON(desc->status & IRQ_GUEST);
desc-> handler = &no_irq_type;
>         }

>         msi_free_vector(entry->vector);
>         spin_unlock_irqrestore(&desc->lock, flags);
>     }
> }

> Best Regards
> Shan Haitao

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