Commit 544c6761 authored by Alexander Graf's avatar Alexander Graf Committed by Benjamin Herrenschmidt

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: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent c8240bd6
...@@ -21,7 +21,8 @@ ...@@ -21,7 +21,8 @@
#define __POWERPC_KVM_HOST_H__ #define __POWERPC_KVM_HOST_H__
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/timer.h> #include <linux/hrtimer.h>
#include <linux/interrupt.h>
#include <linux/types.h> #include <linux/types.h>
#include <linux/kvm_types.h> #include <linux/kvm_types.h>
#include <asm/kvm_asm.h> #include <asm/kvm_asm.h>
...@@ -250,7 +251,8 @@ struct kvm_vcpu_arch { ...@@ -250,7 +251,8 @@ struct kvm_vcpu_arch {
u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */ 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; u64 dec_jiffies;
unsigned long pending_exceptions; unsigned long pending_exceptions;
......
...@@ -18,7 +18,7 @@ ...@@ -18,7 +18,7 @@
*/ */
#include <linux/jiffies.h> #include <linux/jiffies.h>
#include <linux/timer.h> #include <linux/hrtimer.h>
#include <linux/types.h> #include <linux/types.h>
#include <linux/string.h> #include <linux/string.h>
#include <linux/kvm_host.h> #include <linux/kvm_host.h>
...@@ -79,12 +79,13 @@ static int kvmppc_dec_enabled(struct kvm_vcpu *vcpu) ...@@ -79,12 +79,13 @@ static int kvmppc_dec_enabled(struct kvm_vcpu *vcpu)
void kvmppc_emulate_dec(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 #ifdef CONFIG_PPC64
/* POWER4+ triggers a dec interrupt if the value is < 0 */ /* POWER4+ triggers a dec interrupt if the value is < 0 */
if (vcpu->arch.dec & 0x80000000) { if (vcpu->arch.dec & 0x80000000) {
del_timer(&vcpu->arch.dec_timer); hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
kvmppc_core_queue_dec(vcpu); kvmppc_core_queue_dec(vcpu);
return; return;
} }
...@@ -94,12 +95,15 @@ void kvmppc_emulate_dec(struct kvm_vcpu *vcpu) ...@@ -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 * that's how we convert the guest DEC value to the number of
* host ticks. */ * 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(); 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 { } else {
del_timer(&vcpu->arch.dec_timer); hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
} }
} }
......
...@@ -23,6 +23,7 @@ ...@@ -23,6 +23,7 @@
#include <linux/kvm_host.h> #include <linux/kvm_host.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/vmalloc.h> #include <linux/vmalloc.h>
#include <linux/hrtimer.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <asm/cputable.h> #include <asm/cputable.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
...@@ -208,10 +209,25 @@ static void kvmppc_decrementer_func(unsigned long data) ...@@ -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) int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{ {
setup_timer(&vcpu->arch.dec_timer, kvmppc_decrementer_func, hrtimer_init(&vcpu->arch.dec_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
(unsigned long)vcpu); tasklet_init(&vcpu->arch.tasklet, kvmppc_decrementer_func, (ulong)vcpu);
vcpu->arch.dec_timer.function = kvmppc_decrementer_wakeup;
return 0; return 0;
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment