From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: "Stamatis, Ilias" <ilstam@amazon.com>,
"mlevitsk@redhat.com" <mlevitsk@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jmattson@google.com" <jmattson@google.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"mtosatti@redhat.com" <mtosatti@redhat.com>,
"zamsden@gmail.com" <zamsden@gmail.com>,
"wanpengli@tencent.com" <wanpengli@tencent.com>
Subject: Re: [PATCH v3 09/12] KVM: VMX: Remove vmx->current_tsc_ratio and decache_tsc_multiplier()
Date: Tue, 25 May 2021 19:34:03 +0200 [thread overview]
Message-ID: <204c0b60-5e39-eb61-da85-705c56604cde@redhat.com> (raw)
In-Reply-To: <YK0nGozm4PRPv6D7@google.com>
On 25/05/21 18:34, Sean Christopherson wrote:
>> I actually like the idea of storing the expected value in kvm_vcpu and the
>> current value in loaded_vmcs. We might use it for other things such as
>> reload_vmcs01_apic_access_page perhaps.
> I'm not necessarily opposed to aggressively shadowing the VMCS, but if we go
> that route then it should be a standalone series that implements a framework
> that can be easily extended to arbitrary fields. Adding fields to loaded_vmcs
> one at a time will be tedious and error prone. E.g. what makes TSC_MULTIPLIER
> more special than TSC_OFFSET, GUEST_IA32_PAT, GUEST_IA32_DEBUGCTL, GUEST_BNDCFGS,
> and other number of fields that are likely to persist for a given vmcs02?
That it can be changed via ioctls in a way that affects both vmcs01 and
vmcs02. So TSC_MULTIPLIER is in the same boat as TSC_OFFSET, which I
agree we should shadow more aggressively, but the others are different.
Paolo
next prev parent reply other threads:[~2021-05-25 17:34 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 [this message]
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
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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