Re: powernv: Restore SPRs correctly upon wake up from hypervisor state loss
From: Michael Ellerman <hidden>
Date: 2016-09-12 22:09:04
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On Wed, 2016-07-09 at 05:16:30 UTC, "Gautham R. Shenoy" wrote:
From: "Gautham R. Shenoy" <redacted>
pnv_wakeup_tb_loss function currently expects the cr4 to be "eq" if
the CPU is waking up from a complete hypervisor state loss. Hence, it
currently restores the SPR contents only if cr4 is "eq".
However, after the commit bcef83a00dc4 ("powerpc/powernv: Add platform
support for stop instruction"), on ISA_V300 CPUs, the function
pnv_restore_hyp_resource sets cr4 to contain the result of the
comparison between state the CPU has woken up and the first deepest
stop state before calling pnv_wakeup_tb_loss.
Thus if the CPU woke up from a state that is deeper than the first
deepest stop state, cr4 have "gt" set and hence, pnv_wakeup_tb_loss
will fail to restore the SPRs on waking up from such a state.
Fix the code in pnv_wakeup_tb_loss to restore the SPR states when cr4 is
"eq" or "gt".
Fixes: Commit bcef83a00dc4 ("powerpc/powernv: Add platform support for stop instruction")
Signed-off-by: Gautham R. Shenoy <redacted>
Reviewed-by: Shreyas B. Prabhu <redacted>Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/bd00a240dc52e28706fbbe3ace cheers