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KVM: x86: Move TSC offset writes to common code

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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>
This commit is contained in:
Zachary Amsden
2010-08-19 22:07:17 -10:00
committed by Avi Kivity
parent f4e1b3c8bd
commit 99e3e30aee
5 changed files with 33 additions and 9 deletions
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13
arch/x86/kvm/vmx.c
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@@ -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)