From: Maxim Levitsky <mlevitsk@redhat.com>
To: Ilias Stamatis <ilstam@amazon.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com
Cc: 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
Subject: Re: [PATCH v3 10/12] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit
Date: Mon, 24 May 2021 20:54:45 +0300 [thread overview]
Message-ID: <6d8da1e886ebb84ac5168f485148473dc2e2a0b4.camel@redhat.com> (raw)
In-Reply-To: <20210521102449.21505-11-ilstam@amazon.com>
On Fri, 2021-05-21 at 11:24 +0100, Ilias Stamatis wrote:
> Calculate the nested TSC offset and multiplier on entering L2 using the
> corresponding functions. Restore the L1 values on L2's exit.
>
> Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
> ---
> arch/x86/kvm/vmx/nested.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 239154d3e4e7..f75c4174cbcf 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2532,6 +2532,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
> vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat);
> }
>
> + vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(
> + vcpu->arch.l1_tsc_offset,
> + vmx_get_l2_tsc_offset(vcpu),
> + vmx_get_l2_tsc_multiplier(vcpu));
> +
> + vcpu->arch.tsc_scaling_ratio = kvm_calc_nested_tsc_multiplier(
> + vcpu->arch.l1_tsc_scaling_ratio,
> + vmx_get_l2_tsc_multiplier(vcpu));
> +
This code can be in theory put to the common x86 code,
since it uses the vendor callbacks anyway, but this is
probably not worth it.
> vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset);
> if (kvm_has_tsc_control)
> vmcs_write64(TSC_MULTIPLIER, vcpu->arch.tsc_scaling_ratio);
> @@ -3353,8 +3362,6 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
> }
>
> enter_guest_mode(vcpu);
> - if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETTING)
> - vcpu->arch.tsc_offset += vmcs12->tsc_offset;
>
> if (prepare_vmcs02(vcpu, vmcs12, &entry_failure_code)) {
> exit_reason.basic = EXIT_REASON_INVALID_STATE;
> @@ -4462,8 +4469,11 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 vm_exit_reason,
> if (nested_cpu_has_preemption_timer(vmcs12))
> hrtimer_cancel(&to_vmx(vcpu)->nested.preemption_timer);
>
> - if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETTING)
> - vcpu->arch.tsc_offset -= vmcs12->tsc_offset;
> + if (nested_cpu_has(vmcs12, CPU_BASED_USE_TSC_OFFSETTING)) {
> + vcpu->arch.tsc_offset = vcpu->arch.l1_tsc_offset;
> + if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_TSC_SCALING))
> + vcpu->arch.tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio;
> + }
Same here.
>
> if (likely(!vmx->fail)) {
> sync_vmcs02_to_vmcs12(vcpu, vmcs12);
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Best regards,
Maxim Levitsky
next prev parent reply other threads:[~2021-05-24 17:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 10:24 [PATCH v3 00/12] KVM: Implement nested TSC scaling Ilias Stamatis
2021-05-21 10:24 ` [PATCH v3 01/12] math64.h: Add mul_s64_u64_shr() Ilias Stamatis
2021-05-24 17:49 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 02/12] KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch' Ilias Stamatis
2021-05-24 17:49 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 03/12] KVM: X86: Rename kvm_compute_tsc_offset() to kvm_compute_tsc_offset_l1() Ilias Stamatis
2021-05-24 14:21 ` Paolo Bonzini
2021-05-24 17:49 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 04/12] KVM: X86: Add a ratio parameter to kvm_scale_tsc() Ilias Stamatis
2021-05-24 14:23 ` Paolo Bonzini
2021-05-24 15:48 ` Sean Christopherson
2021-05-24 15:56 ` Paolo Bonzini
2021-05-24 17:50 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 05/12] KVM: VMX: Add a TSC multiplier field in VMCS12 Ilias Stamatis
2021-05-21 10:24 ` [PATCH v3 06/12] KVM: X86: Add functions for retrieving L2 TSC fields from common code Ilias Stamatis
2021-05-24 17:50 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 07/12] KVM: X86: Add functions that calculate L2's TSC offset and multiplier Ilias Stamatis
2021-05-24 17:51 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 08/12] KVM: X86: Move write_l1_tsc_offset() logic to common code and rename it Ilias Stamatis
2021-05-24 17:51 ` Maxim Levitsky
2021-05-21 10:24 ` [PATCH v3 09/12] KVM: VMX: Remove vmx->current_tsc_ratio and decache_tsc_multiplier() Ilias Stamatis
2021-05-24 17:53 ` Maxim Levitsky
2021-05-24 18:44 ` Sean Christopherson
2021-05-25 10:41 ` Stamatis, Ilias
2021-05-25 15:58 ` Sean Christopherson
2021-05-25 16:15 ` Paolo Bonzini
2021-05-25 16:34 ` Sean Christopherson
2021-05-25 17:34 ` Paolo Bonzini
2021-05-25 18:21 ` Sean Christopherson
2021-05-25 18:52 ` Stamatis, Ilias
2021-05-25 19:25 ` Stamatis, Ilias
2021-05-25 23:35 ` Sean Christopherson
2021-05-21 10:24 ` [PATCH v3 10/12] KVM: VMX: Set the TSC offset and multiplier on nested entry and exit Ilias Stamatis
2021-05-24 17:54 ` Maxim Levitsky [this message]
2021-05-25 16:05 ` Sean Christopherson
2021-05-21 10:24 ` [PATCH v3 11/12] KVM: VMX: Expose TSC scaling to L2 Ilias Stamatis
2021-05-21 10:24 ` [PATCH v3 12/12] KVM: selftests: x86: Add vmx_nested_tsc_scaling_test Ilias Stamatis
2021-05-24 17:55 ` Maxim Levitsky
2021-05-24 15:37 ` [PATCH v3 00/12] KVM: Implement nested TSC scaling Paolo Bonzini
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