From 4c2155ce81c193788082d4b8cdbc26d79edebc58 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 16 Sep 2008 20:54:47 -0300 Subject: KVM: switch to get_user_pages_fast Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7% faster on VMX. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- virt/kvm/kvm_main.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2907d05cfcc..cd34f73513d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -723,9 +723,6 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_hva); -/* - * Requires current->mm->mmap_sem to be held - */ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) { struct page *page[1]; @@ -741,20 +738,23 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) return page_to_pfn(bad_page); } - npages = get_user_pages(current, current->mm, addr, 1, 1, 0, page, - NULL); + npages = get_user_pages_fast(addr, 1, 1, page); if (unlikely(npages != 1)) { struct vm_area_struct *vma; + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, addr); + if (vma == NULL || addr < vma->vm_start || !(vma->vm_flags & VM_PFNMAP)) { + up_read(¤t->mm->mmap_sem); get_page(bad_page); return page_to_pfn(bad_page); } pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; + up_read(¤t->mm->mmap_sem); BUG_ON(!is_mmio_pfn(pfn)); } else pfn = page_to_pfn(page[0]); -- cgit v1.2.3