From: Paolo Bonzini <pbonzini@redhat.com>
To: Ilias Stamatis <ilstam@amazon.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
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
Subject: Re: [PATCH v3 00/12] KVM: Implement nested TSC scaling
Date: Mon, 24 May 2021 17:37:25 +0200 [thread overview]
Message-ID: <92071380-a81f-7db2-6954-6abd4e390905@redhat.com> (raw)
In-Reply-To: <20210521102449.21505-1-ilstam@amazon.com>
On 21/05/21 12:24, Ilias Stamatis wrote:
> KVM currently supports hardware-assisted TSC scaling but only for L1;
> the feature is not exposed to nested guests. This patch series adds
> support for nested TSC scaling and allows both L1 and L2 to be scaled
> with different scaling factors. That is achieved by "merging" the 01 and
> 02 values together.
>
> Most of the logic in this series is implemented in common code (by doing
> the necessary restructurings), however the patches add support for VMX
> only. Adding support for SVM should be easy at this point and Maxim
> Levitsky has volunteered to do this (thanks!).
>
> Changelog:
> v3:
> - Applied Sean's feedback
> - Refactored patches 7 to 10
>
> v2:
> - Applied all of Maxim's feedback
> - Added a mul_s64_u64_shr function in math64.h
> - Added a separate kvm_scale_tsc_l1 function instead of passing an
> argument to kvm_scale_tsc
> - Implemented the 02 fields calculations in common code
> - Moved all of write_l1_tsc_offset's logic to common code
> - Added a check for whether the TSC is stable in patch 10
> - Used a random L1 factor and a negative offset in patch 10
>
> Ilias Stamatis (12):
> math64.h: Add mul_s64_u64_shr()
> KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch'
> KVM: X86: Rename kvm_compute_tsc_offset() to
> kvm_compute_tsc_offset_l1()
> KVM: X86: Add a ratio parameter to kvm_scale_tsc()
> KVM: VMX: Add a TSC multiplier field in VMCS12
> KVM: X86: Add functions for retrieving L2 TSC fields from common code
> KVM: X86: Add functions that calculate L2's TSC offset and multiplier
> KVM: X86: Move write_l1_tsc_offset() logic to common code and rename
> it
> KVM: VMX: Remove vmx->current_tsc_ratio and decache_tsc_multiplier()
> KVM: VMX: Set the TSC offset and multiplier on nested entry and exit
> KVM: VMX: Expose TSC scaling to L2
> KVM: selftests: x86: Add vmx_nested_tsc_scaling_test
>
> arch/x86/include/asm/kvm-x86-ops.h | 4 +-
> arch/x86/include/asm/kvm_host.h | 14 +-
> arch/x86/kvm/svm/svm.c | 29 ++-
> arch/x86/kvm/vmx/nested.c | 33 ++-
> arch/x86/kvm/vmx/vmcs12.c | 1 +
> arch/x86/kvm/vmx/vmcs12.h | 4 +-
> arch/x86/kvm/vmx/vmx.c | 49 ++--
> arch/x86/kvm/vmx/vmx.h | 11 +-
> arch/x86/kvm/x86.c | 91 +++++--
> include/linux/math64.h | 19 ++
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 1 +
> .../kvm/x86_64/vmx_nested_tsc_scaling_test.c | 242 ++++++++++++++++++
> 13 files changed, 417 insertions(+), 82 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/x86_64/vmx_nested_tsc_scaling_test.c
>
> --
> 2.17.1
>
Queued, thanks.
The new kvm_x86_ops should go in kvm_x86_ops.nested, but those are not
yet static_calls so we can leave that for later.
Paolo
prev parent reply other threads:[~2021-05-24 15:42 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
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 ` Paolo Bonzini [this message]
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