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authorAlexander Graf <agraf@suse.de>2009-11-02 12:02:31 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-11-05 16:51:05 +1100
commit544c6761bb05a1dd19a39cb9bed096273f9bdb36 (patch)
tree66fde2d24a61c3be4712ac2701263aca04f26ebb /arch
parentc8240bd6f0b4b1b21ffd36dd44114d05c7afe0c0 (diff)
Use hrtimers for the decrementer
Following S390's good example we should use hrtimers for the decrementer too! This patch converts the timer from the old mechanism to hrtimers. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/kvm_host.h6
-rw-r--r--arch/powerpc/kvm/emulate.c18
-rw-r--r--arch/powerpc/kvm/powerpc.c20
3 files changed, 33 insertions, 11 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 2cff5fe0cbe..1201f62d0d7 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -21,7 +21,8 @@
#define __POWERPC_KVM_HOST_H__
#include <linux/mutex.h>
-#include <linux/timer.h>
+#include <linux/hrtimer.h>
+#include <linux/interrupt.h>
#include <linux/types.h>
#include <linux/kvm_types.h>
#include <asm/kvm_asm.h>
@@ -250,7 +251,8 @@ struct kvm_vcpu_arch {
u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */
- struct timer_list dec_timer;
+ struct hrtimer dec_timer;
+ struct tasklet_struct tasklet;
u64 dec_jiffies;
unsigned long pending_exceptions;
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 1ec5e07b81e..4a9ac6640fa 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -18,7 +18,7 @@
*/
#include <linux/jiffies.h>
-#include <linux/timer.h>
+#include <linux/hrtimer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
@@ -79,12 +79,13 @@ static int kvmppc_dec_enabled(struct kvm_vcpu *vcpu)
void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
{
- unsigned long nr_jiffies;
+ unsigned long dec_nsec;
+ pr_debug("mtDEC: %x\n", vcpu->arch.dec);
#ifdef CONFIG_PPC64
/* POWER4+ triggers a dec interrupt if the value is < 0 */
if (vcpu->arch.dec & 0x80000000) {
- del_timer(&vcpu->arch.dec_timer);
+ hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
kvmppc_core_queue_dec(vcpu);
return;
}
@@ -94,12 +95,15 @@ void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
* that's how we convert the guest DEC value to the number of
* host ticks. */
+ hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
+ dec_nsec = vcpu->arch.dec;
+ dec_nsec *= 1000;
+ dec_nsec /= tb_ticks_per_usec;
+ hrtimer_start(&vcpu->arch.dec_timer, ktime_set(0, dec_nsec),
+ HRTIMER_MODE_REL);
vcpu->arch.dec_jiffies = get_tb();
- nr_jiffies = vcpu->arch.dec / tb_ticks_per_jiffy;
- mod_timer(&vcpu->arch.dec_timer,
- get_jiffies_64() + nr_jiffies);
} else {
- del_timer(&vcpu->arch.dec_timer);
+ hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
}
}
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index a06ecc3401f..692c3709011 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -23,6 +23,7 @@
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
+#include <linux/hrtimer.h>
#include <linux/fs.h>
#include <asm/cputable.h>
#include <asm/uaccess.h>
@@ -208,10 +209,25 @@ static void kvmppc_decrementer_func(unsigned long data)
}
}
+/*
+ * low level hrtimer wake routine. Because this runs in hardirq context
+ * we schedule a tasklet to do the real work.
+ */
+enum hrtimer_restart kvmppc_decrementer_wakeup(struct hrtimer *timer)
+{
+ struct kvm_vcpu *vcpu;
+
+ vcpu = container_of(timer, struct kvm_vcpu, arch.dec_timer);
+ tasklet_schedule(&vcpu->arch.tasklet);
+
+ return HRTIMER_NORESTART;
+}
+
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
- setup_timer(&vcpu->arch.dec_timer, kvmppc_decrementer_func,
- (unsigned long)vcpu);
+ hrtimer_init(&vcpu->arch.dec_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+ tasklet_init(&vcpu->arch.tasklet, kvmppc_decrementer_func, (ulong)vcpu);
+ vcpu->arch.dec_timer.function = kvmppc_decrementer_wakeup;
return 0;
}