KVM paravirt: Add async PF initialization to PV guest.

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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8b61c93609994dd91e36c25e1b29647ad084eaff..369580da1953ebc5a67c15158d1145524b0237ec 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1707,6 +1707,9 @@ 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 8662ae0a035c1b30277052d138412d596c830a80..2315398230d1a3dd2f3b2052fe32cbea5667fcf5 100644 (file)
--- 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 e6db17976b8224a42cf2d66ae708e2adbe8a5d5e..032d03b6b54aaa01b0858a6d115c73ede759148a 100644 (file)
--- 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
 }