On Mon, Jan 15, 2018 at 07:39:05PM +0000, James Morse wrote: > We expect to have firmware-first handling of RAS SErrors, with errors > notified via an APEI method. For systems without firmware-first, add > some minimal handling to KVM. > > There are two ways KVM can take an SError due to a guest, either may be a > RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, > or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. > > The current SError from EL2 code unmasks SError and tries to fence any > pending SError into a single instruction window. It then leaves SError > unmasked. > > With the v8.2 RAS Extensions we may take an SError for a 'corrected' > error, but KVM is only able to handle SError from EL2 if they occur > during this single instruction window... > > The RAS Extensions give us a new instruction to synchronise and > consume SErrors. The RAS Extensions document (ARM DDI0587), > '2.4.1 ESB and Unrecoverable errors' describes ESB as synchronising > SError interrupts generated by 'instructions, translation table walks, > hardware updates to the translation tables, and instruction fetches on > the same PE'. This makes ESB equivalent to KVMs existing > 'dsb, mrs-daifclr, isb' sequence. > > Use the alternatives to synchronise and consume any SError using ESB > instead of unmasking and taking the SError. Set ARM_EXIT_WITH_SERROR_BIT > in the exit_code so that we can restart the vcpu if it turns out this > SError has no impact on the vcpu. > > Signed-off-by: James Morse <james.morse@xxxxxxx> > --- > Changes since v4: > * Moved the SError handling into handle_exit_early() > * Dropped Marc & Christoffer's Reviewed-by due to handle_exit_early(). > I realize this is queued, but for good measure, I'm still happy with this change after handle_exit_early(). Thanks, -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
