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authorZachary Amsden <zamsden@redhat.com>2010-08-19 22:07:17 -1000
committerAvi Kivity <avi@redhat.com>2010-10-24 10:51:22 +0200
commit99e3e30aee1a326a98bf3a5f47b8622219c685f3 (patch)
tree1b67fc70af33988080784d32725f72b5ce7c07d1 /arch/x86/kvm
parentf4e1b3c8bd2a044cd0ccf80595bfd088a49fe60b (diff)
downloadop-kernel-dev-99e3e30aee1a326a98bf3a5f47b8622219c685f3.zip
op-kernel-dev-99e3e30aee1a326a98bf3a5f47b8622219c685f3.tar.gz
KVM: x86: Move TSC offset writes to common code
Also, ensure that the storing of the offset and the reading of the TSC are never preempted by taking a spinlock. While the lock is overkill now, it is useful later in this patch series. Signed-off-by: Zachary Amsden <zamsden@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/svm.c6
-rw-r--r--arch/x86/kvm/vmx.c13
-rw-r--r--arch/x86/kvm/x86.c18
-rw-r--r--arch/x86/kvm/x86.h2
4 files changed, 30 insertions, 9 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e06f00d..ea41c55 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -915,7 +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_write_tsc_offset(&svm->vcpu, 0-native_read_tsc());
+ kvm_write_tsc(&svm->vcpu, 0);
err = fx_init(&svm->vcpu);
if (err)
@@ -2581,7 +2581,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
switch (ecx) {
case MSR_IA32_TSC:
- svm_write_tsc_offset(vcpu, data - native_read_tsc());
+ kvm_write_tsc(vcpu, data);
break;
case MSR_STAR:
svm->vmcb->save.star = data;
@@ -3551,6 +3551,8 @@ static struct kvm_x86_ops svm_x86_ops = {
.set_supported_cpuid = svm_set_supported_cpuid,
.has_wbinvd_exit = svm_has_wbinvd_exit,
+
+ .write_tsc_offset = svm_write_tsc_offset,
};
static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d9bec5e..138746d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1146,10 +1146,9 @@ 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
+ * writes 'offset' into guest's timestamp counter offset register
*/
-static void vmx_write_tsc_offset(u64 offset)
+static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
vmcs_write64(TSC_OFFSET, offset);
}
@@ -1224,7 +1223,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct shared_msr_entry *msr;
- u64 host_tsc;
int ret = 0;
switch (msr_index) {
@@ -1254,8 +1252,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
vmcs_writel(GUEST_SYSENTER_ESP, data);
break;
case MSR_IA32_TSC:
- rdtscll(host_tsc);
- vmx_write_tsc_offset(data - host_tsc);
+ kvm_write_tsc(vcpu, data);
break;
case MSR_IA32_CR_PAT:
if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
@@ -2653,7 +2650,7 @@ 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);
- vmx_write_tsc_offset(0-native_read_tsc());
+ kvm_write_tsc(&vmx->vcpu, 0);
return 0;
}
@@ -4348,6 +4345,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
.set_supported_cpuid = vmx_set_supported_cpuid,
.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
+
+ .write_tsc_offset = vmx_write_tsc_offset,
};
static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8b0c51a..886132b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -895,6 +895,22 @@ static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info *
static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
+void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
+{
+ struct kvm *kvm = vcpu->kvm;
+ u64 offset;
+ unsigned long flags;
+
+ spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
+ offset = data - native_read_tsc();
+ kvm_x86_ops->write_tsc_offset(vcpu, offset);
+ spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
+
+ /* Reset of TSC must disable overshoot protection below */
+ vcpu->arch.hv_clock.tsc_timestamp = 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_tsc);
+
static void kvm_write_guest_time(struct kvm_vcpu *v)
{
struct timespec ts;
@@ -5495,6 +5511,8 @@ struct kvm *kvm_arch_create_vm(void)
/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */
set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);
+ spin_lock_init(&kvm->arch.tsc_write_lock);
+
return kvm;
}
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index b7a4047..2d6385e 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -68,4 +68,6 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
+void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data);
+
#endif
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