From 7ec54588210df29ea637e6054489bc942c0ef371 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Thu, 20 Dec 2007 19:18:23 -0500 Subject: KVM: Add kvm_read_guest_atomic() In preparation for a mmu spinlock, add kvm_read_guest_atomic() and use it in fetch() and prefetch_page(). Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- virt/kvm/kvm_main.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'virt/kvm') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 678e80561b7..8d0b7c16c2f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -541,6 +541,26 @@ int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len) } EXPORT_SYMBOL_GPL(kvm_read_guest); +int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data, + unsigned long len) +{ + int r; + unsigned long addr; + gfn_t gfn = gpa >> PAGE_SHIFT; + int offset = offset_in_page(gpa); + + addr = gfn_to_hva(kvm, gfn); + if (kvm_is_error_hva(addr)) + return -EFAULT; + pagefault_disable(); + r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len); + pagefault_enable(); + if (r) + return -EFAULT; + return 0; +} +EXPORT_SYMBOL(kvm_read_guest_atomic); + int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data, int offset, int len) { -- cgit v1.2.2