> Yes, this is a bug. How about moving the last
>
> spin_unlock_irqrestore(&iommu->lock, flags);
>
> outside of the if-statement?
That looks good to me :-)
Cheers,
Mark
> Allen
>
> >-----Original Message-----
> >From: M.A. Williamson [mailto:maw48@xxxxxxxxxxxxxxxx] On
> >Behalf Of Mark Williamson
> >Sent: Wednesday, May 30, 2007 6:38 PM
> >To: xen-devel@xxxxxxxxxxxxxxxxxxx
> >Cc: Kay, Allen M
> >Subject: Re: [Xen-devel] [VTD][patch 1/5] HVM device
> >assignment using vt-d
> >
> >On Wednesday 30 May 2007, Kay, Allen M wrote:
> >> vtd1.patch:
> >> - vt-d specific code
> >> - low risk changes in common code
> >>
> >> Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>
> >> Signed-off-by: Xiaohui Xin <xiaohui.xin@xxxxxxxxx>
> >
> >iommu_set_root_entry can exit with locking. Is this
> >unintentional behaviour?
> >
> >/* iommu handling */
> >static int iommu_set_root_entry(struct iommu *iommu)
> >{
> > void *addr;
> > u32 cmd, sts;
> > struct root_entry *root;
> > unsigned long flags;
> >
> > if (iommu == NULL)
> > gdprintk(XENLOG_ERR VTDPREFIX,
> > "iommu_set_root_entry: iommu == NULL\n");
> >
> > spin_lock_irqsave(&iommu->lock, flags);
> >
> >MAW: if iommu->root_entry is already set at this point
> >
> > if (!iommu->root_entry) {
> > spin_unlock_irqrestore(&iommu->lock, flags);
> > root = (struct root_entry *)alloc_xenheap_page();
> > memset((u8*)root, 0, PAGE_SIZE);
> > iommu_flush_cache_page(iommu, root);
> > spin_lock_irqsave(&iommu->lock, flags);
> >
> > if (!root && !iommu->root_entry) {
> > spin_unlock_irqrestore(&iommu->lock, flags);
> > return -ENOMEM;
> > }
> >
> > if (!iommu->root_entry)
> > iommu->root_entry = root;
> > else /* somebody is fast */
> > free_xenheap_page((void *)root);
> > spin_unlock_irqrestore(&iommu->lock, flags);
> > }
> >
> >MAW: then we never unlock iommu->lock. In all other cases
> >it's released
> >before we return.
> >
> >Cheers,
> >Mark
> >
> >--
> >Dave: Just a question. What use is a unicyle with no seat?
> >And no pedals!
> >Mark: To answer a question with a question: What use is a skateboard?
> >Dave: Skateboards have wheels.
> >Mark: My wheel has a wheel!
--
Dave: Just a question. What use is a unicyle with no seat? And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!
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