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charset="UTF-8" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Sean Christopherson Cc: kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , David Stevens , loongarch@lists.linux.dev, kvmarm@lists.linux.dev, linux-riscv@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Add a kvm_follow_pfn() wrapper, kvm_lookup_pfn(), to allow looking up a gfn=>pfn mapping without the caller getting a reference to any underlying page. The API will be used in flows that want to know if a gfn points at a valid pfn, but don't actually need to do anything with the pfn. Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 82ca0971c156..5a572cef4adc 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1212,6 +1212,8 @@ 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); +kvm_pfn_t kvm_lookup_pfn(struct kvm *kvm, gfn_t gfn); + kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn); kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault, bool *writable); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0b3c0bddaa07..ad84dab8c5dc 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3118,6 +3118,22 @@ kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn) } EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn); +kvm_pfn_t kvm_lookup_pfn(struct kvm *kvm, gfn_t gfn) +{ + struct page *refcounted_page = NULL; + struct kvm_follow_pfn kfp = { + .slot = gfn_to_memslot(kvm, gfn), + .gfn = gfn, + .flags = FOLL_WRITE, + .refcounted_page = &refcounted_page, + }; + kvm_pfn_t pfn; + + pfn = kvm_follow_pfn(&kfp); + kvm_release_page_unused(refcounted_page); + return pfn; +} + int kvm_prefetch_pages(struct kvm_memory_slot *slot, gfn_t gfn, struct page **pages, int nr_pages) { -- 2.46.0.rc1.232.g9752f9e123-goog