From 1c7b627e930624dd64ee906df554c8f2bad628ff Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 10 Oct 2024 11:23:45 -0700 Subject: KVM: Add kvm_faultin_pfn() to specifically service guest page faults MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a new dedicated API, kvm_faultin_pfn(), for servicing guest page faults, i.e. for getting pages/pfns that will be mapped into the guest via an mmu_notifier-protected KVM MMU. Keep struct kvm_follow_pfn buried in internal code, as having __kvm_faultin_pfn() take "out" params is actually cleaner for several architectures, e.g. it allows the caller to have its own "page fault" structure without having to marshal data to/from kvm_follow_pfn. Long term, common KVM would ideally provide a kvm_page_fault structure, a la x86's struct of the same name. But all architectures need to be converted to a common API before that can happen. Tested-by: Alex Bennée Signed-off-by: Sean Christopherson Tested-by: Dmitry Osipenko Signed-off-by: Paolo Bonzini Message-ID: <20241010182427.1434605-44-seanjc@google.com> --- virt/kvm/kvm_main.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index becf640e369c..f79745d6500c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3092,6 +3092,28 @@ kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_pfn); +kvm_pfn_t __kvm_faultin_pfn(const struct kvm_memory_slot *slot, gfn_t gfn, + unsigned int foll, bool *writable, + struct page **refcounted_page) +{ + struct kvm_follow_pfn kfp = { + .slot = slot, + .gfn = gfn, + .flags = foll, + .map_writable = writable, + .refcounted_page = refcounted_page, + }; + + if (WARN_ON_ONCE(!writable || !refcounted_page)) + return KVM_PFN_ERR_FAULT; + + *writable = false; + *refcounted_page = NULL; + + return kvm_follow_pfn(&kfp); +} +EXPORT_SYMBOL_GPL(__kvm_faultin_pfn); + int kvm_prefetch_pages(struct kvm_memory_slot *slot, gfn_t gfn, struct page **pages, int nr_pages) { -- cgit v1.2.3