| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 207/209] powerpc/time: Fix clockevent_decrementer initalisation for PR KVM | Date | Tue, 12 Nov 2019 20:50:23 -0500 |
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From: Michael Ellerman <mpe@ellerman.id.au>
[ Upstream commit b4d16ab58c41ff0125822464bdff074cebd0fe47 ]
In the recent commit 8b78fdb045de ("powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer") we changed the way we initialise the decrementer clockevent(s).
We no longer initialise the mult & shift values of decrementer_clockevent itself.
This has the effect of breaking PR KVM, because it uses those values in kvmppc_emulate_dec(). The symptom is guest kernels spin forever mid-way through boot.
For now fix it by assigning back to decrementer_clockevent the mult and shift values.
Fixes: 8b78fdb045de ("powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/powerpc/kernel/time.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 6a1f0a084ca35..7707990c4c169 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -988,6 +988,10 @@ static void register_decrementer_clockevent(int cpu) printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", dec->name, dec->mult, dec->shift, cpu); + + /* Set values for KVM, see kvm_emulate_dec() */ + decrementer_clockevent.mult = dec->mult; + decrementer_clockevent.shift = dec->shift; } static void enable_large_decrementer(void) -- 2.20.1
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