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Date:   Mon, 31 Jul 2023 14:50:07 -0700
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Subject: Re: [PATCH v7 02/12] KVM: arm64: Use kvm_arch_flush_remote_tlbs()
From:   Sean Christopherson <seanjc@google.com>
To:     Marc Zyngier <maz@kernel.org>
Cc:     Raghavendra Rao Ananta <rananta@google.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Anup Patel <anup@brainfault.org>,
        Atish Patra <atishp@atishpatra.org>,
        Jing Zhang <jingzhangos@google.com>,
        Reiji Watanabe <reijiw@google.com>,
        Colton Lewis <coltonlewis@google.com>,
        David Matlack <dmatlack@google.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
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On Thu, Jul 27, 2023, Marc Zyngier wrote:
> On Sat, 22 Jul 2023 03:22:41 +0100,
> Raghavendra Rao Ananta <rananta@google.com> wrote:
> > 
> > Stop depending on CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL and opt to
> > standardize on kvm_arch_flush_remote_tlbs() since it avoids
> > duplicating the generic TLB stats across architectures that implement
> > their own remote TLB flush.
> > 
> > This adds an extra function call to the ARM64 kvm_flush_remote_tlbs()
> > path, but that is a small cost in comparison to flushing remote TLBs.
> 
> Well, there is no such thing as a "remote TLB" anyway. We either have
> a non-shareable or inner-shareable invalidation. The notion of remote
> would imply that we track who potentially has a TLB, which we
> obviously don't.

Maybe kvm_arch_flush_vm_tlbs()?  The "remote" part is misleading even on x86 when
running on Hyper-V, as the flush may be done via a single hypercall and by kicking
"remote" vCPUs.