[PATCH v7 07/12] Add async PF initialization to PV guest.

Gleb Natapov
2010-10-14T09:22:51Z

Enable async PF in a guest if async PF capability is discovered.

Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
Documentation/kernel-parameters.txt | 3 +
arch/x86/include/asm/kvm_para.h | 6 ++
arch/x86/kernel/kvm.c | 92 +++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8dc2548..0bd2203 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1699,6 +1699,9 @@ and is between 256 and 4096 characters. It is defined in the file

no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver

+ no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
+ fault handling.
+
nolapic [X86-32,APIC] Do not enable or use the local APIC.

nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 8662ae0..2315398 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -65,6 +65,12 @@ struct kvm_mmu_op_release_pt {
__u64 pt_phys;
};

+struct kvm_vcpu_pv_apf_data {
+ __u32 reason;
+ __u8 pad[60];
+ __u32 enabled;
+};
+
#ifdef __KERNEL__
#include <asm/processor.h>

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index e6db179..032d03b 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -27,16 +27,30 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/hardirq.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
#include <asm/timer.h>
+#include <asm/cpu.h>

#define MMU_QUEUE_SIZE 1024

+static int kvmapf = 1;
+
+static int parse_no_kvmapf(char *arg)
+{
+ kvmapf = 0;
+ return 0;
+}
+
+early_param("no-kvmapf", parse_no_kvmapf);
+
struct kvm_para_state {
u8 mmu_queue[MMU_QUEUE_SIZE];
int mmu_queue_len;
};

static DEFINE_PER_CPU(struct kvm_para_state, para_state);
+static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);

static struct kvm_para_state *kvm_para_state(void)
{
@@ -231,12 +245,86 @@ static void __init paravirt_ops_setup(void)
#endif
}

+void __cpuinit kvm_guest_cpu_init(void)
+{
+ if (!kvm_para_available())
+ return;
+
+ if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
+ u64 pa = __pa(&__get_cpu_var(apf_reason));
+
+ wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
+ __get_cpu_var(apf_reason).enabled = 1;
+ printk(KERN_INFO"KVM setup async PF for cpu %d\n",
+ smp_processor_id());
+ }
+}
+
+static void kvm_pv_disable_apf(void *unused)
+{
+ if (!__get_cpu_var(apf_reason).enabled)
+ return;
+
+ wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
+ __get_cpu_var(apf_reason).enabled = 0;
+
+ printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
+ smp_processor_id());
+}
+
+static int kvm_pv_reboot_notify(struct notifier_block *nb,
+ unsigned long code, void *unused)
+{
+ if (code == SYS_RESTART)
+ on_each_cpu(kvm_pv_disable_apf, NULL, 1);
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kvm_pv_reboot_nb = {
+ .notifier_call = kvm_pv_reboot_notify,
+};
+
#ifdef CONFIG_SMP
static void __init kvm_smp_prepare_boot_cpu(void)
{
WARN_ON(kvm_register_clock("primary cpu clock"));
+ kvm_guest_cpu_init();
native_smp_prepare_boot_cpu();
}
+
+static void kvm_guest_cpu_online(void *dummy)
+{
+ kvm_guest_cpu_init();
+}
+
+static void kvm_guest_cpu_offline(void *dummy)
+{
+ kvm_pv_disable_apf(NULL);
+}
+
+static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ int cpu = (unsigned long)hcpu;
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_DOWN_FAILED:
+ case CPU_ONLINE_FROZEN:
+ smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
+ break;
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
+ .notifier_call = kvm_cpu_notify,
+};
#endif

void __init kvm_guest_init(void)
@@ -245,7 +333,11 @@ void __init kvm_guest_init(void)
return;

paravirt_ops_setup();
+ register_reboot_notifier(&kvm_pv_reboot_nb);
#ifdef CONFIG_SMP
smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
+ register_cpu_notifier(&kvm_cpu_notifier);
+#else
+ kvm_guest_cpu_init();
#endif