KVM: x86: Convert TSC writes to TSC offset writes

Change svm / vmx to be the same internally and write TSC offset
instead of bare TSC in helper functions.  Isolated as a single
patch to contain code movement.

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

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index af5b9ea..e06f00d 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -701,6 +701,20 @@ static void init_sys_seg(struct vmcb_seg *seg, uint32_t type)
        seg->base = 0;
 }
 
+static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
+{
+       struct vcpu_svm *svm = to_svm(vcpu);
+       u64 g_tsc_offset = 0;
+
+       if (is_nested(svm)) {
+               g_tsc_offset = svm->vmcb->control.tsc_offset -
+                              svm->nested.hsave->control.tsc_offset;
+               svm->nested.hsave->control.tsc_offset = offset;
+       }
+
+       svm->vmcb->control.tsc_offset = offset + g_tsc_offset;
+}
+
 static void init_vmcb(struct vcpu_svm *svm)
 {
        struct vmcb_control_area *control = &svm->vmcb->control;
@@ -901,7 +915,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
        svm->vmcb_pa = page_to_pfn(page) << PAGE_SHIFT;
        svm->asid_generation = 0;
        init_vmcb(svm);
-       svm->vmcb->control.tsc_offset = 0-native_read_tsc();
+       svm_write_tsc_offset(&svm->vcpu, 0-native_read_tsc());
 
        err = fx_init(&svm->vcpu);
        if (err)
@@ -2566,20 +2580,9 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
        struct vcpu_svm *svm = to_svm(vcpu);
 
        switch (ecx) {
-       case MSR_IA32_TSC: {
-               u64 tsc_offset = data - native_read_tsc();
-               u64 g_tsc_offset = 0;
-
-               if (is_nested(svm)) {
-                       g_tsc_offset = svm->vmcb->control.tsc_offset -
-                                      svm->nested.hsave->control.tsc_offset;
-                       svm->nested.hsave->control.tsc_offset = tsc_offset;
-               }
-
-               svm->vmcb->control.tsc_offset = tsc_offset + g_tsc_offset;
-
+       case MSR_IA32_TSC:
+               svm_write_tsc_offset(vcpu, data - native_read_tsc());
                break;
-       }
        case MSR_STAR:
                svm->vmcb->save.star = data;
                break;

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4fbab24..d9bec5e 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1149,9 +1149,9 @@ static u64 guest_read_tsc(void)
  * writes 'guest_tsc' into guest's timestamp counter "register"
  * guest_tsc = host_tsc + tsc_offset ==> tsc_offset = guest_tsc - host_tsc
  */
-static void guest_write_tsc(u64 guest_tsc, u64 host_tsc)
+static void vmx_write_tsc_offset(u64 offset)
 {
-       vmcs_write64(TSC_OFFSET, guest_tsc - host_tsc);
+       vmcs_write64(TSC_OFFSET, offset);
 }
 
 /*
@@ -1255,7 +1255,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
                break;
        case MSR_IA32_TSC:
                rdtscll(host_tsc);
-               guest_write_tsc(data, host_tsc);
+               vmx_write_tsc_offset(data - host_tsc);
                break;
        case MSR_IA32_CR_PAT:
                if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
@@ -2512,7 +2512,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 {
        u32 host_sysenter_cs, msr_low, msr_high;
        u32 junk;
-       u64 host_pat, tsc_this;
+       u64 host_pat;
        unsigned long a;
        struct desc_ptr dt;
        int i;
@@ -2653,8 +2653,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
                vmx->vcpu.arch.cr4_guest_owned_bits |= X86_CR4_PGE;
        vmcs_writel(CR4_GUEST_HOST_MASK, ~vmx->vcpu.arch.cr4_guest_owned_bits);
 
-       tsc_this = native_read_tsc();
-       guest_write_tsc(0, tsc_this);
+       vmx_write_tsc_offset(0-native_read_tsc());
 
        return 0;
 }