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[35.185.214.157]) by smtp.gmail.com with ESMTPSA id x25sm25440480pfu.113.2021.12.30.11.45.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Dec 2021 11:45:59 -0800 (PST) Date: Thu, 30 Dec 2021 19:45:56 +0000 From: Sean Christopherson To: David Stevens Cc: Marc Zyngier , Paolo Bonzini , James Morse , Alexandru Elisei , Suzuki K Poulose , Will Deacon , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v5 3/4] KVM: arm64/mmu: use gfn_to_pfn_page Message-ID: References: <20211129034317.2964790-1-stevensd@google.com> <20211129034317.2964790-4-stevensd@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211129034317.2964790-4-stevensd@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 29, 2021, David Stevens wrote: > @@ -1142,14 +1146,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > > /* Mark the page dirty only if the fault is handled successfully */ > if (writable && !ret) { > - kvm_set_pfn_dirty(pfn); > + if (page) > + kvm_set_pfn_dirty(pfn); If kvm_set_page_dirty() is changed to be less dumb: if (page) kvm_set_page_dirty(page); > mark_page_dirty_in_slot(kvm, memslot, gfn); > } > > out_unlock: > spin_unlock(&kvm->mmu_lock); > - kvm_set_pfn_accessed(pfn); > - kvm_release_pfn_clean(pfn); > + if (page) { > + kvm_set_pfn_accessed(pfn); > + put_page(page); Oof, KVM's helpers are stupid. Take a page, convert it to a pfn, then convert it back to a page, just to mark it dirty or put a ref. Can you fold the below (completely untested) patch in before the x86/arm64 patches? That way this code can be: if (page) kvm_release_page_accessed(page); and x86 can do: if (fault->page) kvm_release_page_clean(page); instead of open-coding put_page(). >From a8af0c60d7f6e77bbc7310d898211c43ae075cf8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 30 Dec 2021 11:40:58 -0800 Subject: [PATCH] KVM: Clean up and enhance helpers for releasing pages/pfns Tweak kvm_release_page_clean() and kvm_release_page_dirty() to avoid pointlessly converting to a pfn and back to a page, and add an "accessed" variant that will be used in a future arm64 patch. No functional change intended. Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8eb0f762a82c..f75129f641e9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2876,29 +2876,37 @@ void kvm_release_page_clean(struct page *page) { WARN_ON(is_error_page(page)); - kvm_release_pfn_clean(page_to_pfn(page)); + put_page(page); } EXPORT_SYMBOL_GPL(kvm_release_page_clean); void kvm_release_pfn_clean(kvm_pfn_t pfn) { if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn)) - put_page(pfn_to_page(pfn)); + kvm_release_page_clean(page); } EXPORT_SYMBOL_GPL(kvm_release_pfn_clean); +void kvm_release_page_accessed(struct page *page) +{ + mark_page_accessed(page); + + kvm_release_page_clean(page); +} +EXPORT_SYMBOL_GPL(kvm_release_page_accessed); + void kvm_release_page_dirty(struct page *page) { - WARN_ON(is_error_page(page)); + SetPageDirty(page); - kvm_release_pfn_dirty(page_to_pfn(page)); + kvm_release_page_clean(page); } EXPORT_SYMBOL_GPL(kvm_release_page_dirty); void kvm_release_pfn_dirty(kvm_pfn_t pfn) { - kvm_set_pfn_dirty(pfn); - kvm_release_pfn_clean(pfn); + if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_pfn(pfn)) + kvm_release_page_dirty(pfn_to_page(pfn)); } EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty); -- 2.34.1.448.ga2b2bfdf31-goog