linux-kernel - Re: [RFC PATCH 03/24] KVM: SVM: Add helpers to set/clear ASID flush in VMCB

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Message-ID: <aFmE7-osX2rmdGL5@google.com>
Date: Mon, 23 Jun 2025 09:46:39 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Yosry Ahmed <yosry.ahmed@...ux.dev>
Cc: Paolo Bonzini <pbonzini@...hat.com>, Jim Mattson <jmattson@...gle.com>, 
	Maxim Levitsky <mlevitsk@...hat.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, 
	Rik van Riel <riel@...riel.com>, Tom Lendacky <thomas.lendacky@....com>, x86@...nel.org, 
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 03/24] KVM: SVM: Add helpers to set/clear ASID flush
 in VMCB

On Wed, Mar 26, 2025, Yosry Ahmed wrote:
> Incoming changes will add more code paths that set tlb_ctl to
> TLB_CONTROL_FLUSH_ASID, and will eliminate the use of
> TLB_CONTROL_FLUSH_ALL_ASID except as fallback when FLUSHBYASID is not
> available. Introduce set/clear helpers to set tlb_ctl to
> TLB_CONTROL_FLUSH_ASID or TLB_CONTROL_DO_NOTHING.
> 
> Opportunistically move the TLB_CONTROL_* definitions to
> arch/x86/kvm/svm/svm.h as they are not used outside of arch/x86/kvm/svm/.
> 
> Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
> ---
>  arch/x86/include/asm/svm.h |  5 -----
>  arch/x86/kvm/svm/nested.c  |  2 +-
>  arch/x86/kvm/svm/sev.c     |  2 +-
>  arch/x86/kvm/svm/svm.c     |  4 ++--
>  arch/x86/kvm/svm/svm.h     | 15 +++++++++++++++
>  5 files changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
> index 9b7fa99ae9513..a97da63562eb3 100644
> --- a/arch/x86/include/asm/svm.h
> +++ b/arch/x86/include/asm/svm.h
> @@ -171,11 +171,6 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
>  };
>  
>  
> -#define TLB_CONTROL_DO_NOTHING 0
> -#define TLB_CONTROL_FLUSH_ALL_ASID 1
> -#define TLB_CONTROL_FLUSH_ASID 3
> -#define TLB_CONTROL_FLUSH_ASID_LOCAL 7

These should stay in asm/svm.h as they are architectural definitions.  KVM's
headers are anything but organized, but my goal is to eventually have the asm/
headers hold most/all architectural definitions, while KVM's internal headers
hold KVM-internal stuff.