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Commit 86ab8cff authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity
Browse files

KVM: introduce gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic 



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: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 037d92dc

virt/kvm/kvm_main.c

+23 −4
Original line number Diff line number Diff line
@@ -1002,6 +1002,25 @@ 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 +1293,10 @@ 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 +1331,11 @@ 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;