From: Sean Christopherson <seanjc@google.com>
To: Ilias Stamatis <ilstam@amazon.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, mlevitsk@redhat.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 v2 02/10] KVM: X86: Store L1's TSC scaling ratio in 'struct kvm_vcpu_arch'
Date: Tue, 18 May 2021 22:52:57 +0000 [thread overview]
Message-ID: <YKRFSaktB4+tgFUH@google.com> (raw)
In-Reply-To: <20210512150945.4591-3-ilstam@amazon.com>
On Wed, May 12, 2021, Ilias Stamatis wrote:
> Store L1's scaling ratio in that struct like we already do for L1's TSC
s/that struct/kvm_vcpu_arch. Forcing the reader to look at the subject to
understand the changelog is annoying, especially when it saves all of a handful
of characters. E.g. I often read patches without the subject in scope.
> offset. This allows for easy save/restore when we enter and then exit
> the nested guest.
>
> Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
...
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9b6bca616929..07cf5d7ece38 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2185,6 +2185,7 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
>
> /* Guest TSC same frequency as host TSC? */
> if (!scale) {
> + vcpu->arch.l1_tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
> vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
Looks like these are always set as a pair, maybe add a helper, e.g.
static void kvm_set_l1_tsc_scaling_ratio(u64 ratio)
{
vcpu->arch.l1_tsc_scaling_ratio = ratio;
vcpu->arch.tsc_scaling_ratio = ratio;
}
> return 0;
> }
> @@ -2211,7 +2212,7 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
> return -1;
> }
>
> - vcpu->arch.tsc_scaling_ratio = ratio;
> + vcpu->arch.l1_tsc_scaling_ratio = vcpu->arch.tsc_scaling_ratio = ratio;
> return 0;
> }
>
> @@ -2223,6 +2224,7 @@ static int kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
> /* tsc_khz can be zero if TSC calibration fails */
> if (user_tsc_khz == 0) {
> /* set tsc_scaling_ratio to a safe value */
> + vcpu->arch.l1_tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
> vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
> return -1;
> }
> @@ -2459,7 +2461,7 @@ static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
>
> static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment)
> {
> - if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio)
> + if (vcpu->arch.l1_tsc_scaling_ratio != kvm_default_tsc_scaling_ratio)
> WARN_ON(adjustment < 0);
> adjustment = kvm_scale_tsc(vcpu, (u64) adjustment);
> adjust_tsc_offset_guest(vcpu, adjustment);
> --
> 2.17.1
>
next prev parent reply other threads:[~2021-05-18 22:53 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 [this message]
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 ` [PATCH v2 06/10] KVM: X86: Add functions that calculate the 02 TSC offset and multiplier Ilias Stamatis
2021-05-18 23:21 ` 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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