Prev: [PATCH v5 10/12] Handle async PF in non preemptable context
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From: Gleb Natapov on 19 Jul 2010 11:40
Enable async PF in a guest if async PF capability is discovered.

Signed-off-by: Gleb Natapov <gleb(a)redhat.com>
---
arch/x86/include/asm/kvm_para.h | 5 +++
arch/x86/kernel/kvm.c | 68 +++++++++++++++++++++++++++++++++++++++
2 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 5b05e9f..f1662d7 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -65,6 +65,11 @@ struct kvm_mmu_op_release_pt {
__u64 pt_phys;
};

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

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index e6db179..5177dd1 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -27,7 +27,10 @@
#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

@@ -37,6 +40,7 @@ struct kvm_para_state {
};

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 +235,72 @@ 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)) {
+ u64 pa = __pa(&__get_cpu_var(apf_reason));
+
+ if (native_write_msr_safe(MSR_KVM_ASYNC_PF_EN,
+ pa | KVM_ASYNC_PF_ENABLED, pa >> 32))
+ return;
+ __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 int __cpuinit kvm_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ kvm_guest_cpu_init();
+ 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 +309,11 @@ 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
}
--
1.7.1

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Next: [PATCH v5 09/12] Retry fault before vmentry