When L2 is entered we need to "merge" the TSC multiplier and TSC offset
values of 01 and 12 together.
The merging is done using the following equations:
offset_02 = ((offset_01 * mult_12) >> shift_bits) + offset_12
mult_02 = (mult_01 * mult_12) >> shift_bits
Where shift_bits is kvm_tsc_scaling_ratio_frac_bits.
Signed-off-by: Ilias Stamatis <ilstam@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/x86.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4c4a3fefff57..57a25d8e8b0f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1793,6 +1793,8 @@ static inline bool kvm_is_supported_user_return_msr(u32 msr)
u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);
u64 kvm_scale_tsc_l1(struct kvm_vcpu *vcpu, u64 tsc);
u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc);
+void kvm_set_02_tsc_offset(struct kvm_vcpu *vcpu);
+void kvm_set_02_tsc_multiplier(struct kvm_vcpu *vcpu);
unsigned long kvm_get_linear_rip(struct kvm_vcpu *vcpu);
bool kvm_is_linear_rip(struct kvm_vcpu *vcpu, unsigned long linear_rip);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 84af1af7a2cc..1db6cfc2079f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2346,6 +2346,35 @@ u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
}
EXPORT_SYMBOL_GPL(kvm_read_l1_tsc);
+void kvm_set_02_tsc_offset(struct kvm_vcpu *vcpu)
+{
+ u64 l2_offset = static_call(kvm_x86_get_l2_tsc_offset)(vcpu);
+ u64 l2_multiplier = static_call(kvm_x86_get_l2_tsc_multiplier)(vcpu);
+
+ if (l2_multiplier != kvm_default_tsc_scaling_ratio) {
+ vcpu->arch.tsc_offset = mul_s64_u64_shr(
+ (s64) vcpu->arch.l1_tsc_offset,
+ l2_multiplier,
+ kvm_tsc_scaling_ratio_frac_bits);
+ }
+
+ vcpu->arch.tsc_offset += l2_offset;
+}
+EXPORT_SYMBOL_GPL(kvm_set_02_tsc_offset);
+
+void kvm_set_02_tsc_multiplier(struct kvm_vcpu *vcpu)
+{
+ u64 l2_multiplier = static_call(kvm_x86_get_l2_tsc_multiplier)(vcpu);
+
+ if (l2_multiplier != kvm_default_tsc_scaling_ratio) {
+ vcpu->arch.tsc_scaling_ratio = mul_u64_u64_shr(
+ vcpu->arch.l1_tsc_scaling_ratio,
+ l2_multiplier,
+ kvm_tsc_scaling_ratio_frac_bits);
+ }
+}
+EXPORT_SYMBOL_GPL(kvm_set_02_tsc_multiplier);
+
static void kvm_vcpu_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
vcpu->arch.l1_tsc_offset = offset;
--
2.17.1
