[Xen-devel] map_domain_page_global() and interrupts

[Andrew Gallagher <ajcg@xxxxxxxxxxx>]

In the file xen/arch/x86/x86_32/domain_page.c, the 
map_domain_page_global function has the following assertion:
ASSERT(!in_irq() && local_irq_is_enabled()).  This assertion is followed 
by use of a spin lock without disabling then reenabling irqs.
The assertion that the function is not called from an interrupted context 
seems to flag this function as not interrupt safe.  Why is this?  Is the 
use of the IOREMAP_VIRT not interrupt safe itself.  The only reason this 
seems to be not interrupt safe is becuase of the use of a spinlock without 
disabling and reenabling irqs.
My question is that, if interrupts are disabled then reenabled before and 
after acquiring and releasing the spinlock, is it then ok to call this 
function from the context of an interrupt?
Thanks,
Andrew

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