On Tue, Oct 27, 2015 at 04:13:56PM +1100, Paul Mackerras wrote: > When handling a hypervisor data or instruction storage interrupt (HDSI > or HISI), we look up the SLB entry for the address being accessed in > order to translate the effective address to a virtual address which can > be looked up in the guest HPT. This lookup can occasionally fail due > to the guest replacing an SLB entry without invalidating the evicted > SLB entry. In this situation an ERAT (effective to real address > translation cache) entry can persist and be used by the hardware even > though there is no longer a corresponding SLB entry. > > Previously we would just deliver a data or instruction storage interrupt > (DSI or ISI) to the guest in this case. However, this is not correct > and has been observed to cause guests to crash, typically with a > data storage protection interrupt on a store to the vmemmap area. > > Instead, what we do now is to synthesize a data or instruction segment > interrupt. That should cause the guest to reload an appropriate entry > into the SLB and retry the faulting instruction. If it still faults, > we should find an appropriate SLB entry next time and be able to handle > the fault. > > Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx> Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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