From: Ilias Stamatis <ilstam@amazon.com>
To: <kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<pbonzini@redhat.com>
Cc: <mlevitsk@redhat.com>, <seanjc@google.com>, <vkuznets@redhat.com>,
<wanpengli@tencent.com>, <jmattson@google.com>, <joro@8bytes.org>,
<zamsden@gmail.com>, <mtosatti@redhat.com>, <dwmw@amazon.co.uk>,
<ilstam@amazon.com>
Subject: [PATCH v2 06/10] KVM: X86: Add functions that calculate the 02 TSC offset and multiplier
Date: Wed, 12 May 2021 16:09:41 +0100 [thread overview]
Message-ID: <20210512150945.4591-7-ilstam@amazon.com> (raw)
In-Reply-To: <20210512150945.4591-1-ilstam@amazon.com>
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@amazon.com>
---
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
next prev parent reply other threads:[~2021-05-12 15:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 15:09 [PATCH v2 00/10] KVM: Implement nested TSC scaling Ilias Stamatis
2021-05-12 15:09 ` [PATCH v2 01/10] math64.h: Add mul_s64_u64_shr() Ilias Stamatis
2021-05-18 22:36 ` Sean Christopherson
2021-05-12 15:09 ` [PATCH v2 02/10] KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch' Ilias Stamatis
2021-05-18 22:52 ` Sean Christopherson
2021-05-19 8:54 ` Stamatis, Ilias
2021-05-12 15:09 ` [PATCH v2 03/10] KVM: X86: Add kvm_scale_tsc_l1() and kvm_compute_tsc_offset_l1() Ilias Stamatis
2021-05-18 23:04 ` Sean Christopherson
2021-05-19 9:02 ` Stamatis, Ilias
2021-05-19 15:40 ` Sean Christopherson
2021-05-20 18:27 ` Stamatis, Ilias
2021-05-12 15:09 ` [PATCH v2 04/10] KVM: VMX: Add a TSC multiplier field in VMCS12 Ilias Stamatis
2021-05-12 15:09 ` [PATCH v2 05/10] KVM: X86: Add functions for retrieving L2 TSC fields from common code Ilias Stamatis
2021-05-12 15:09 ` Ilias Stamatis [this message]
2021-05-18 23:21 ` [PATCH v2 06/10] KVM: X86: Add functions that calculate the 02 TSC offset and multiplier Sean Christopherson
2021-05-19 10:15 ` Stamatis, Ilias
2021-05-12 15:09 ` [PATCH v2 07/10] KVM: X86: Move write_l1_tsc_offset() logic to common code and rename it Ilias Stamatis
2021-05-19 0:05 ` Sean Christopherson
2021-05-19 11:45 ` Stamatis, Ilias
2021-05-19 15:49 ` Sean Christopherson
2021-05-12 15:09 ` [PATCH v2 08/10] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit Ilias Stamatis
2021-05-19 0:07 ` Sean Christopherson
2021-05-19 11:55 ` Stamatis, Ilias
2021-05-12 15:09 ` [PATCH v2 09/10] KVM: VMX: Expose TSC scaling to L2 Ilias Stamatis
2021-05-12 15:09 ` [PATCH v2 10/10] KVM: selftests: x86: Add vmx_nested_tsc_scaling_test Ilias Stamatis
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