KVM: ia64: Create inline function kvm_get_itc() to centralize ITC reading.

Move all reading of special register 'AR_ITC' into two functions, one
in the kernel and one in the VMM module. When running on SN2, base the
result on the RTC rather the system ITC, as the ITC isn't
synchronized.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 18 insertions, 2 deletions

diff --git a/arch/ia64/kvm/vcpu.c b/arch/ia64/kvm/vcpu.c
index a18ee17b9192..a2c6c15e4761 100644
--- a/arch/ia64/kvm/vcpu.c
+++ b/arch/ia64/kvm/vcpu.c
@@ -788,13 +788,29 @@ void vcpu_set_fpreg(struct kvm_vcpu *vcpu, unsigned long reg,
                 setfpreg(reg, val, regs);   /* FIXME: handle NATs later*/
 }
 
+/*
+ * The Altix RTC is mapped specially here for the vmm module
+ */
+#define SN_RTC_BASE     (u64 *)(KVM_VMM_BASE+(1UL<<KVM_VMM_SHIFT))
+static long kvm_get_itc(struct kvm_vcpu *vcpu)
+{
+#if defined(CONFIG_IA64_SGI_SN2) || defined(CONFIG_IA64_GENERIC)
+        struct kvm *kvm = (struct kvm *)KVM_VM_BASE;
+
+        if (kvm->arch.is_sn2)
+                return (*SN_RTC_BASE);
+        else
+#endif
+                return ia64_getreg(_IA64_REG_AR_ITC);
+}
+
 /************************************************************************
  * lsapic timer
  ***********************************************************************/
 u64 vcpu_get_itc(struct kvm_vcpu *vcpu)
 {
         unsigned long guest_itc;
-        guest_itc = VMX(vcpu, itc_offset) + ia64_getreg(_IA64_REG_AR_ITC);
+        guest_itc = VMX(vcpu, itc_offset) + kvm_get_itc(vcpu);
 
         if (guest_itc >= VMX(vcpu, last_itc)) {
                 VMX(vcpu, last_itc) = guest_itc;
@@ -809,7 +825,7 @@ static void vcpu_set_itc(struct kvm_vcpu *vcpu, u64 val)
         struct kvm_vcpu *v;
         struct kvm *kvm;
         int i;
-        long itc_offset = val - ia64_getreg(_IA64_REG_AR_ITC);
+        long itc_offset = val - kvm_get_itc(vcpu);
         unsigned long vitv = VCPU(vcpu, itv);
 
         kvm = (struct kvm *)KVM_VM_BASE;