From 887c08ac191efb103e33e589aacbc2ce1a3f131e Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Sun, 22 Aug 2010 19:10:28 +0800 Subject: [PATCH] KVM: MMU: introduce hva_to_pfn_atomic function Introduce hva_to_pfn_atomic(), it's the fast path and can used in atomic context, the later patch will use it Signed-off-by: Xiao Guangrong Signed-off-by: Marcelo Tosatti --- include/linux/kvm_host.h | 7 +++++++ virt/kvm/kvm_main.c | 30 +++++++++++++++++++----------- 2 files changed, 26 insertions(+), 11 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c13cc48697aa..307d0e2c0f59 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -296,6 +296,7 @@ void kvm_release_page_dirty(struct page *page); void kvm_set_page_dirty(struct page *page); void kvm_set_page_accessed(struct page *page); +pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr); pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn); pfn_t gfn_to_pfn_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn); @@ -518,6 +519,12 @@ static inline void kvm_guest_exit(void) current->flags &= ~PF_VCPU; } +static inline unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, + gfn_t gfn) +{ + return slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE; +} + static inline gpa_t gfn_to_gpa(gfn_t gfn) { return (gpa_t)gfn << PAGE_SHIFT; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index da117a6b1e2e..08bd304f8bc7 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -927,11 +927,6 @@ int memslot_id(struct kvm *kvm, gfn_t gfn) return memslot - slots->memslots; } -static unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot, gfn_t gfn) -{ - return slot->userspace_addr + (gfn - slot->base_gfn) * PAGE_SIZE; -} - unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) { struct kvm_memory_slot *slot; @@ -943,19 +938,25 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_hva); -static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr) +static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic) { struct page *page[1]; int npages; pfn_t pfn; - might_sleep(); - - npages = get_user_pages_fast(addr, 1, 1, page); + if (atomic) + npages = __get_user_pages_fast(addr, 1, 1, page); + else { + might_sleep(); + npages = get_user_pages_fast(addr, 1, 1, page); + } if (unlikely(npages != 1)) { struct vm_area_struct *vma; + if (atomic) + goto return_fault_page; + down_read(¤t->mm->mmap_sem); if (is_hwpoison_address(addr)) { up_read(¤t->mm->mmap_sem); @@ -968,6 +969,7 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr) if (vma == NULL || addr < vma->vm_start || !(vma->vm_flags & VM_PFNMAP)) { up_read(¤t->mm->mmap_sem); +return_fault_page: get_page(fault_page); return page_to_pfn(fault_page); } @@ -981,6 +983,12 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr) return pfn; } +pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr) +{ + return hva_to_pfn(kvm, addr, true); +} +EXPORT_SYMBOL_GPL(hva_to_pfn_atomic); + pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) { unsigned long addr; @@ -991,7 +999,7 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) return page_to_pfn(bad_page); } - return hva_to_pfn(kvm, addr); + return hva_to_pfn(kvm, addr, false); } EXPORT_SYMBOL_GPL(gfn_to_pfn); @@ -999,7 +1007,7 @@ pfn_t gfn_to_pfn_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn) { unsigned long addr = gfn_to_hva_memslot(slot, gfn); - return hva_to_pfn(kvm, addr); + return hva_to_pfn(kvm, addr, false); } struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)