[Xen-devel] [PATCH 13/16] vmx: nest: L2 tsc

[Qing He <qing.he@xxxxxxxxx>]

L2 TSC needs special handling, either rdtsc exiting is
turned on or off

Signed-off-by: Qing He <qing.he@xxxxxxxxx>
Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>

---

diff -r 0f6400481299 xen/arch/x86/hvm/vmx/nest.c
--- a/xen/arch/x86/hvm/vmx/nest.c       Wed Sep 08 18:43:13 2010 +0800
+++ b/xen/arch/x86/hvm/vmx/nest.c       Wed Sep 08 18:52:00 2010 +0800
@@ -647,6 +647,18 @@
  * Nested VMX context switch
  */
 
+u64 vmx_nest_get_tsc_offset(struct vcpu *v)
+{
+    u64 offset = 0;
+    struct vmx_nest_struct *nest = &v->arch.hvm_vmx.nest;
+
+    if ( __get_vvmcs(nest->vvmcs, CPU_BASED_VM_EXEC_CONTROL) &
+         CPU_BASED_USE_TSC_OFFSETING )
+        offset = __get_vvmcs(nest->vvmcs, TSC_OFFSET);
+
+    return offset;
+}
+
 static unsigned long vmcs_gstate_field[] = {
     /* 16 BITS */
     GUEST_ES_SELECTOR,
@@ -818,6 +830,7 @@
 
 static void load_vvmcs_guest_state(struct vmx_nest_struct *nest)
 {
+    struct vcpu *v = current;
     int i;
 
     /* vvmcs.gstate to svmcs.gstate */
@@ -828,6 +841,8 @@
     hvm_set_cr4(__get_vvmcs(nest->vvmcs, GUEST_CR4));
     hvm_set_cr3(__get_vvmcs(nest->vvmcs, GUEST_CR3));
 
+    hvm_funcs.set_tsc_offset(v, v->arch.hvm_vcpu.cache_tsc_offset);
+
     vvmcs_to_shadow(nest->vvmcs, VM_ENTRY_INTR_INFO);
     vvmcs_to_shadow(nest->vvmcs, VM_ENTRY_EXCEPTION_ERROR_CODE);
     vvmcs_to_shadow(nest->vvmcs, VM_ENTRY_INSTRUCTION_LEN);
@@ -936,6 +951,7 @@
 
 static void load_vvmcs_host_state(struct vmx_nest_struct *nest)
 {
+    struct vcpu *v = current;
     int i;
     u64 r;
 
@@ -949,6 +965,8 @@
     hvm_set_cr4(__get_vvmcs(nest->vvmcs, HOST_CR4));
     hvm_set_cr3(__get_vvmcs(nest->vvmcs, HOST_CR3));
 
+    hvm_funcs.set_tsc_offset(v, v->arch.hvm_vcpu.cache_tsc_offset);
+
     __set_vvmcs(nest->vvmcs, VM_ENTRY_INTR_INFO, 0);
 }
 
@@ -1205,6 +1223,21 @@
 
         if ( ctrl & CPU_BASED_RDTSC_EXITING )
             nest->vmexit_pending = 1;
+        else
+        {
+            uint64_t tsc;
+
+            /*
+             * special handler is needed if L1 doesn't intercept rdtsc,
+             * avoiding changing guest_tsc and messing up timekeeping in L1
+             */
+            tsc = hvm_get_guest_tsc(v);
+            tsc += __get_vvmcs(nest->vvmcs, TSC_OFFSET);
+            regs->eax = (uint32_t)tsc;
+            regs->edx = (uint32_t)(tsc >> 32);
+
+            bypass_l0 = 1;
+        }
 
         break;
     }
diff -r 0f6400481299 xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Wed Sep 08 18:43:13 2010 +0800
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Wed Sep 08 18:52:00 2010 +0800
@@ -969,6 +969,10 @@
 static void vmx_set_tsc_offset(struct vcpu *v, u64 offset)
 {
     vmx_vmcs_enter(v);
+
+    if ( v->arch.hvm_vcpu.in_nesting )
+        offset += vmx_nest_get_tsc_offset(v);
+
     __vmwrite(TSC_OFFSET, offset);
 #if defined (__i386__)
     __vmwrite(TSC_OFFSET_HIGH, offset >> 32);
diff -r 0f6400481299 xen/include/asm-x86/hvm/vmx/nest.h
--- a/xen/include/asm-x86/hvm/vmx/nest.h        Wed Sep 08 18:43:13 2010 +0800
+++ b/xen/include/asm-x86/hvm/vmx/nest.h        Wed Sep 08 18:52:00 2010 +0800
@@ -69,6 +69,8 @@
                                             unsigned long value);
 void vmx_nest_update_exception_bitmap(struct vcpu *v, unsigned long value);
 
+u64 vmx_nest_get_tsc_offset(struct vcpu *v);
+
 void vmx_nest_idtv_handling(void);
 
 int vmx_nest_l2_vmexit_handler(struct cpu_user_regs *regs,

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