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Fri, 26 Jul 2024 16:54:16 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 26 Jul 2024 16:51:57 -0700 In-Reply-To: <20240726235234.228822-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240726235234.228822-1-seanjc@google.com> X-Mailer: git-send-email 2.46.0.rc1.232.g9752f9e123-goog Message-ID: <20240726235234.228822-49-seanjc@google.com> Subject: [PATCH v12 48/84] KVM: Move x86's API to release a faultin page to common KVM From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson Cc: kvm@vger.kernel.org, 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-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , David Stevens Move KVM x86's helper that "finishes" the faultin process to common KVM so that the logic can be shared across all architectures. Note, not all architectures implement a fast page fault path, but the gist of the comment applies to all architectures. Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 24 ++---------------------- include/linux/kvm_host.h | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 95beb50748fc..2a0cfa225c8d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4323,28 +4323,8 @@ static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn, static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, int r) { - lockdep_assert_once(lockdep_is_held(&vcpu->kvm->mmu_lock) || - r == RET_PF_RETRY); - - if (!fault->refcounted_page) - return; - - /* - * If the page that KVM got from the *primary MMU* is writable, and KVM - * installed or reused a SPTE, mark the page/folio dirty. Note, this - * may mark a folio dirty even if KVM created a read-only SPTE, e.g. if - * the GFN is write-protected. Folios can't be safely marked dirty - * outside of mmu_lock as doing so could race with writeback on the - * folio. As a result, KVM can't mark folios dirty in the fast page - * fault handler, and so KVM must (somewhat) speculatively mark the - * folio dirty if KVM could locklessly make the SPTE writable. - */ - if (r == RET_PF_RETRY) - kvm_release_page_unused(fault->refcounted_page); - else if (!fault->map_writable) - kvm_release_page_clean(fault->refcounted_page); - else - kvm_release_page_dirty(fault->refcounted_page); + kvm_release_faultin_page(vcpu->kvm, fault->refcounted_page, + r == RET_PF_RETRY, fault->map_writable); } static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9d2a97eb30e4..91341cdc6562 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1216,6 +1216,32 @@ static inline void kvm_release_page_unused(struct page *page) void kvm_release_page_clean(struct page *page); void kvm_release_page_dirty(struct page *page); +static inline void kvm_release_faultin_page(struct kvm *kvm, struct page *page, + bool unused, bool dirty) +{ + lockdep_assert_once(lockdep_is_held(&kvm->mmu_lock) || unused); + + if (!page) + return; + + /* + * If the page that KVM got from the *primary MMU* is writable, and KVM + * installed or reused a SPTE, mark the page/folio dirty. Note, this + * may mark a folio dirty even if KVM created a read-only SPTE, e.g. if + * the GFN is write-protected. Folios can't be safely marked dirty + * outside of mmu_lock as doing so could race with writeback on the + * folio. As a result, KVM can't mark folios dirty in the fast page + * fault handler, and so KVM must (somewhat) speculatively mark the + * folio dirty if KVM could locklessly make the SPTE writable. + */ + if (unused) + kvm_release_page_unused(page); + else if (dirty) + kvm_release_page_dirty(page); + else + kvm_release_page_clean(page); +} + kvm_pfn_t kvm_lookup_pfn(struct kvm *kvm, gfn_t gfn); kvm_pfn_t __kvm_faultin_pfn(const struct kvm_memory_slot *slot, gfn_t gfn, unsigned int foll, bool *writable,