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powerpc/powernv: Fixes for hypervisor doorbell handling

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Since we can now use hypervisor doorbells for host IPIs, this makes
sure we clear the host IPI flag when taking a doorbell interrupt, and
clears any pending doorbell IPI in pnv_smp_cpu_kill_self() (as we
already do for IPIs sent via the XICS interrupt controller).  Otherwise
if there did happen to be a leftover pending doorbell interrupt for
an offline CPU thread for any reason, it would prevent that thread from
going into a power-saving mode; it would instead keep waking up because
of the interrupt.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras
2015-03-19 19:29:01 +11:00
committed by Michael Ellerman
parent 06e5801b8c
commit 755563bc79
4 changed files with 20 additions and 2 deletions
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14
arch/powerpc/platforms/powernv/smp.c
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@@ -33,6 +33,8 @@
#include <asm/runlatch.h>
#include <asm/code-patching.h>
#include <asm/dbell.h>
#include <asm/kvm_ppc.h>
#include <asm/ppc-opcode.h>
#include "powernv.h"
@@ -149,7 +151,7 @@ static int pnv_smp_cpu_disable(void)
static void pnv_smp_cpu_kill_self(void)
{
unsigned int cpu;
unsigned long srr1;
unsigned long srr1, wmask;
u32 idle_states;
/* Standard hot unplug procedure */
@@ -161,6 +163,10 @@ static void pnv_smp_cpu_kill_self(void)
generic_set_cpu_dead(cpu);
smp_wmb();
wmask = SRR1_WAKEMASK;
if (cpu_has_feature(CPU_FTR_ARCH_207S))
wmask = SRR1_WAKEMASK_P8;
idle_states = pnv_get_supported_cpuidle_states();
/* We don't want to take decrementer interrupts while we are offline,
* so clear LPCR:PECE1. We keep PECE2 enabled.
@@ -191,10 +197,14 @@ static void pnv_smp_cpu_kill_self(void)
* having finished executing in a KVM guest, then srr1
* contains 0.
*/
if ((srr1 & SRR1_WAKEMASK) == SRR1_WAKEEE) {
if ((srr1 & wmask) == SRR1_WAKEEE) {
icp_native_flush_interrupt();
local_paca->irq_happened &= PACA_IRQ_HARD_DIS;
smp_mb();
} else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
kvmppc_set_host_ipi(cpu, 0);
}
if (cpu_core_split_required())