Re: [PATCH/RFC 4/4, second shot]KVM uses "account_guest_time()"

[Laurent Vivier]

KVM updates vtime in task_struct to allow account_guest_time() to modify user,
system and guest time in cpustat accordingly.

Index: kvm/drivers/kvm/Kconfig
===================================================================
--- kvm.orig/drivers/kvm/Kconfig        2007-08-17 10:24:46.000000000 +0200
+++ kvm/drivers/kvm/Kconfig     2007-08-17 10:25:25.000000000 +0200
@@ -41,4 +41,10 @@
          Provides support for KVM on AMD processors equipped with the AMD-V
          (SVM) extensions.
 
+config GUEST_ACCOUNTING
+       bool "Virtual Machine accounting support"
+       depends on KVM
+       ---help---
+         Allows to account CPU time used by the Virtual Machines.
+
 endif # VIRTUALIZATION
Index: kvm/drivers/kvm/kvm.h
===================================================================
--- kvm.orig/drivers/kvm/kvm.h  2007-08-17 10:19:30.000000000 +0200
+++ kvm/drivers/kvm/kvm.h       2007-08-17 10:21:56.000000000 +0200
@@ -589,6 +589,19 @@
 
 int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run);
 
+#ifdef CONFIG_GUEST_ACCOUNTING
+static inline ktime_t kvm_guest_enter(void)
+{
+        return ktime_get();
+}
+
+static inline void kvm_guest_exit(ktime_t enter)
+{
+        ktime_t delta = ktime_sub(ktime_get(), enter);
+        current->vtime = ktime_add(current->vtime, delta);
+}
+#endif
+
 static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
                                     u32 error_code)
 {
Index: kvm/drivers/kvm/svm.c
===================================================================
--- kvm.orig/drivers/kvm/svm.c  2007-08-17 10:22:07.000000000 +0200
+++ kvm/drivers/kvm/svm.c       2007-08-17 10:23:32.000000000 +0200
@@ -1392,6 +1392,9 @@
        u16 gs_selector;
        u16 ldt_selector;
        int r;
+#ifdef CONFIG_GUEST_ACCOUNTING
+       ktime_t now;
+#endif
 
 again:
        r = kvm_mmu_reload(vcpu);
@@ -1404,6 +1407,9 @@
        clgi();
 
        vcpu->guest_mode = 1;
+#ifdef CONFIG_GUEST_ACCOUNTING
+       now = kvm_guest_enter();
+#endif
        if (vcpu->requests)
                if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
                    svm_flush_tlb(vcpu);
@@ -1536,6 +1542,9 @@
 #endif
                : "cc", "memory" );
 
+#ifdef CONFIG_GUEST_ACCOUNTING
+       kvm_guest_exit(now);
+#endif
        vcpu->guest_mode = 0;
 
        if (vcpu->fpu_active) {
Index: kvm/drivers/kvm/vmx.c
===================================================================
--- kvm.orig/drivers/kvm/vmx.c  2007-08-17 10:23:36.000000000 +0200
+++ kvm/drivers/kvm/vmx.c       2007-08-17 10:24:37.000000000 +0200
@@ -2052,6 +2052,9 @@
        struct vcpu_vmx *vmx = to_vmx(vcpu);
        u8 fail;
        int r;
+#ifdef CONFIG_GUEST_ACCOUNTING
+       ktime_t now;
+#endif
 
 preempted:
        if (vcpu->guest_debug.enabled)
@@ -2078,6 +2081,9 @@
        local_irq_disable();
 
        vcpu->guest_mode = 1;
+#ifdef CONFIG_GUEST_ACCOUNTING
+       now = kvm_guest_enter();
+#endif
        if (vcpu->requests)
                if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
                    vmx_flush_tlb(vcpu);
@@ -2198,6 +2204,9 @@
                [cr2]"i"(offsetof(struct kvm_vcpu, cr2))
              : "cc", "memory" );
 
+#ifdef CONFIG_GUEST_ACCOUNTING
+       kvm_guest_exit(now);
+#endif
        vcpu->guest_mode = 0;
        local_irq_enable();