Messages in this thread Patch in this message | | | Date | Tue, 07 Aug 2012 17:50:26 +0800 | From | Xiao Guangrong <> | Subject | [PATCH v5 04/12] KVM: introduce gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic |
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This set of functions is only used to read data from host space, in the later patch, we will only get a readonly hva in gfn_to_hva_read, and the function name is a good hint to let gfn_to_hva_read to pair with kvm_read_hva()/kvm_read_hva_atomic()
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> --- virt/kvm/kvm_main.c | 29 +++++++++++++++++++++++++---- 1 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 543f9b7..26ffc87 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1002,6 +1002,27 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_hva);
+/* + * The hva returned by this function is only allowed to be read. + * It should pair with kvm_read_hva() or kvm_read_hva_atomic(). + */ +static unsigned long gfn_to_hva_read(struct kvm *kvm, gfn_t gfn) +{ + return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL); +} + +static int kvm_read_hva(void *data, void __user *hva, int len) +{ + return __copy_from_user(data, hva, len); + +} + +static int kvm_read_hva_atomic(void *data, void __user *hva, int len) +{ + return __copy_from_user_inatomic(data, hva, len); + +} + int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int write, struct page **page) { @@ -1274,10 +1295,10 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset, int r; unsigned long addr;
- addr = gfn_to_hva(kvm, gfn); + addr = gfn_to_hva_read(kvm, gfn); if (kvm_is_error_hva(addr)) return -EFAULT; - r = __copy_from_user(data, (void __user *)addr + offset, len); + r = kvm_read_hva(data, (void __user *)addr + offset, len); if (r) return -EFAULT; return 0; @@ -1312,11 +1333,11 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data, gfn_t gfn = gpa >> PAGE_SHIFT; int offset = offset_in_page(gpa);
- addr = gfn_to_hva(kvm, gfn); + addr = gfn_to_hva_read(kvm, gfn); if (kvm_is_error_hva(addr)) return -EFAULT; pagefault_disable(); - r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len); + r = kvm_read_hva_atomic(data, (void __user *)addr + offset, len); pagefault_enable(); if (r) return -EFAULT; -- 1.7.7.6
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