Re: [Xen-devel] [PATCH v5 5/7] VT-d: Refactor iommu_ops .map_page() and unmap_page()

["Xu, Quan" <quan.xu@xxxxxxxxx>]

> On February 26, 2016 4:15pm,  <JBeulich@xxxxxxxx> wrote:
> >>> On 26.02.16 at 08:37, <quan.xu@xxxxxxxxx> wrote:
> > On February 25, 2016 8:24pm, <JBeulich@xxxxxxxx> wrote:
> >> >>> On 25.02.16 at 13:14, <quan.xu@xxxxxxxxx> wrote:
> >> > On February 25, 2016 4:59pm, <JBeulich@xxxxxxxx> wrote:


> Nevertheless I'd recommend not mixing things for the pcidevs one, as its uses
> are scattered around too much for it to be reasonably possible to prove
> correctness if done that way.


> Instead please make the lock a static variable in e.g.
> xen/drivers/pci/pci.c or xen/drivers/passthrough/pci.c, and force
> acquire/release to go through helper functions. That way we can ensure
> instance gets left. The only safe alternative to this would be to rename the 
> lock
> at once, or to make it read/write one (but then recursion would be allowed 
> only
> for the read cases, and aiui you'd need the write variant for your use).
> 

Jan, sorry, I don't follow this comment. Is it necessary for v6 patch set?

Quan

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