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AJvYcCV6hfapwTplAYXgPay8XVe7tuJFH9JmdGkXoBM7Dj7atwmXpXAqmWS1hcJk8fyBqKzQ4X+YMtFZwVSg+eDtjy7ldSo= X-Gm-Message-State: AOJu0YzxpxNkjtmaAoBaYi0mC88SmI8XY0rNeVEF+mpINM0t/BZB6JPX FUfkIvM843zo0Ob27fXTT6DMPg9OZgROxBdbiJIFvt++buMgdTuvoR+NLWVX69Q9VoniQRXzsPG hwg== X-Google-Smtp-Source: AGHT+IGomtDJcb51lvQMFTT5YaGoxW/vZTzkUSuhiTLoa8vZxcxiKEVXH4dmB1G1pZ9i7NSp+ryn6A1areA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:ad8d:0:b0:dc6:e5d3:5f03 with SMTP id z13-20020a25ad8d000000b00dc6e5d35f03mr543024ybi.4.1713535088599; Fri, 19 Apr 2024 06:58:08 -0700 (PDT) Date: Fri, 19 Apr 2024 06:58:06 -0700 In-Reply-To: <20240419112432.GB2972@willie-the-truck> Mime-Version: 1.0 References: <20240405115815.3226315-1-pbonzini@redhat.com> <20240405115815.3226315-2-pbonzini@redhat.com> <20240412104408.GA27645@willie-the-truck> <86jzl2sovz.wl-maz@kernel.org> <86h6g5si0m.wl-maz@kernel.org> <20240418141932.GA1855@willie-the-truck> <20240419112432.GB2972@willie-the-truck> Message-ID: Subject: Re: [PATCH 1/4] KVM: delete .change_pte MMU notifier callback From: Sean Christopherson To: Will Deacon Cc: Marc Zyngier , Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Oliver Upton , Tianrui Zhao , Bibo Mao , Thomas Bogendoerfer , Nicholas Piggin , Anup Patel , Atish Patra , Andrew Morton , David Hildenbrand , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="us-ascii" X-Rspamd-Queue-Id: AF55B40023 X-Stat-Signature: gwpijbhzbp7jdttz6sjzzfjp8sfuoizi X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1713535089-737318 X-HE-Meta: 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 WRCCWzd4 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000922, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Apr 19, 2024, Will Deacon wrote: > > @@ -663,10 +669,22 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm, > > break; > > } > > r.ret |= range->handler(kvm, &gfn_range); > > + > > + /* > > + * Use a precise gfn-based TLB flush when possible, as > > + * most mmu_notifier events affect a small-ish range. > > + * Fall back to a full TLB flush if the gfn-based flush > > + * fails, and don't bother trying the gfn-based flush > > + * if a full flush is already pending. > > + */ > > + if (range->flush_on_ret && !need_flush && r.ret && > > + kvm_arch_flush_remote_tlbs_range(kvm, gfn_range.start, > > + gfn_range.end - gfn_range.start + 1)) > > What's that '+ 1' needed for here? (a) To see if you're paying attention. (b) Because more is always better. (c) Because math is hard. (d) Because I haven't tested this. (e) Both (c) and (d).