The following patch allows to activate a partition reference
time enlightenment that is based on the host platform's support
for an Invariant Time Stamp Counter (iTSC).
v2 -> v3
Handle TSC sequence, scale, and offest changing during migration.
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 29 +++++++++++++++++++++++++++--
2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2fd0753..81fdff0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -607,6 +607,7 @@ struct kvm_arch {
u64 hv_hypercall;
u64 hv_ref_count;
u64 hv_tsc_page;
+ u64 hv_ref_time;
#ifdef CONFIG_KVM_MMU_AUDIT
int audit_point;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5e4e495a..cb6766a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1882,14 +1882,19 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32
msr, u64 data)
break;
}
gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
- addr = gfn_to_hva(kvm, data >>
- HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT);
+ addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr))
return 1;
+ tsc_ref.tsc_sequence =
+ boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ? 1 : 0;
+ tsc_ref.tsc_scale =
+ ((10000LL << 32) / vcpu->arch.virtual_tsc_khz) << 32;
+ tsc_ref.tsc_offset = 0;
if (__copy_to_user((void __user *)addr, &tsc_ref,
sizeof(tsc_ref)))
return 1;
mark_page_dirty(kvm, gfn);
kvm->arch.hv_tsc_page = data;
+ kvm->arch.hv_ref_count = 0;
break;
}
default:
@@ -3879,6 +3884,19 @@ long kvm_arch_vm_ioctl(struct file *filp,
local_irq_enable();
kvm->arch.kvmclock_offset = delta;
kvm_gen_update_masterclock(kvm);
+
+ if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
+ HV_REFERENCE_TSC_PAGE* tsc_ref;
+ u64 curr_time;
+ tsc_ref = (HV_REFERENCE_TSC_PAGE*)gfn_to_hva(kvm,
+ kvm->arch.hv_tsc_page >>
HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT);
+ tsc_ref->tsc_sequence =
+ boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ?
tsc_ref->tsc_sequence + 1 : 0;
+ tsc_ref->tsc_scale = ((10000LL << 32) /
__get_cpu_var(cpu_tsc_khz)) << 32;
+ curr_time = (((tsc_ref->tsc_scale >> 32) *
native_read_tsc()) >> 32) +
+ tsc_ref->tsc_offset;
+ tsc_ref->tsc_offset = kvm->arch.hv_ref_time - curr_time;
+ }
break;
}
case KVM_GET_CLOCK: {
@@ -3896,6 +3914,13 @@ long kvm_arch_vm_ioctl(struct file *filp,
if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
goto out;
r = 0;
+ if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
+ HV_REFERENCE_TSC_PAGE* tsc_ref;
+ tsc_ref = (HV_REFERENCE_TSC_PAGE*)gfn_to_hva(kvm,
+ kvm->arch.hv_tsc_page >>
HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT);
+ kvm->arch.hv_ref_time = (((tsc_ref->tsc_scale >> 32) *
+ native_read_tsc()) >> 32) + tsc_ref->tsc_offset;
+ }
break;
}
--
1.8.1.4
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