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authorMarcelo Tosatti <mtosatti@redhat.com>2008-09-16 20:54:47 -0300
committerAvi Kivity <avi@redhat.com>2008-10-15 14:25:06 +0200
commit4c2155ce81c193788082d4b8cdbc26d79edebc58 (patch)
tree5c028fe4a18c55b5c0e9c4e80be459dad3f96da7 /virt
parent777b3f49d297e387866604093b635e5bc9b9d2a6 (diff)
downloadlinux-linaro-stable-4c2155ce81c193788082d4b8cdbc26d79edebc58.tar.gz
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 <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2907d05cfcc3..cd34f73513d3 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(&current->mm->mmap_sem);
vma = find_vma(current->mm, addr);
+
if (vma == NULL || addr < vma->vm_start ||
!(vma->vm_flags & VM_PFNMAP)) {
+ up_read(&current->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(&current->mm->mmap_sem);
BUG_ON(!is_mmio_pfn(pfn));
} else
pfn = page_to_pfn(page[0]);