Re: [Xen-devel] kmap_atomic issue with SLES11SP1 32bit XEN driver code

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.12.11 at 22:34, Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx> wrote:
> I don't know much about the SLES kernels, but if it uses lazy page
> updating it might be hitting:
> 
> 2cd1c8d x86/paravirt: PTE updates in k(un)map_atomic need to be
> synchronous, regardless of lazy_mmu mode

We use lazy mode, but only in non-IRQ (and theoretically
preemption-enabled; theoretically because PREEMPT isn't a
permitted config option in the forward ported kernels) context.
That is, we'd be susceptible to this problem only if within a
lazy-mode enabled section k{,un}map_atomic were used
synchronously (which I'd consider a coding mistake).

Jan


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