xen: Add privcmd device driver

Access to arbitrary hypercalls is currently provided via xenfs. This
adds a standard character device to handle this. The support in xenfs
remains for backward compatibility and uses the device driver code.

Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

4 files changed, 3 insertions, 403 deletions

diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
index 4fde9440fe1f..5d45ff13cc01 100644
--- a/drivers/xen/xenfs/Makefile
+++ b/drivers/xen/xenfs/Makefile
@@ -1,4 +1,4 @@
 obj-$(CONFIG_XENFS) += xenfs.o
 
-xenfs-y			  = super.o xenbus.o privcmd.o
+xenfs-y			  = super.o xenbus.o
 xenfs-$(CONFIG_XEN_DOM0) += xenstored.o
diff --git a/drivers/xen/xenfs/privcmd.c b/drivers/xen/xenfs/privcmd.c
deleted file mode 100644
index dbd3b16fd131..000000000000
--- a/drivers/xen/xenfs/privcmd.c
+++ /dev/null
@@ -1,400 +0,0 @@
-/******************************************************************************
- * privcmd.c
- *
- * Interface to privileged domain-0 commands.
- *
- * Copyright (c) 2002-2004, K A Fraser, B Dragovic
- */
-
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/string.h>
-#include <linux/errno.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/uaccess.h>
-#include <linux/swap.h>
-#include <linux/highmem.h>
-#include <linux/pagemap.h>
-#include <linux/seq_file.h>
-
-#include <asm/pgalloc.h>
-#include <asm/pgtable.h>
-#include <asm/tlb.h>
-#include <asm/xen/hypervisor.h>
-#include <asm/xen/hypercall.h>
-
-#include <xen/xen.h>
-#include <xen/privcmd.h>
-#include <xen/interface/xen.h>
-#include <xen/features.h>
-#include <xen/page.h>
-#include <xen/xen-ops.h>
-
-#ifndef HAVE_ARCH_PRIVCMD_MMAP
-static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma);
-#endif
-
-static long privcmd_ioctl_hypercall(void __user *udata)
-{
-	struct privcmd_hypercall hypercall;
-	long ret;
-
-	if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
-		return -EFAULT;
-
-	ret = privcmd_call(hypercall.op,
-			   hypercall.arg[0], hypercall.arg[1],
-			   hypercall.arg[2], hypercall.arg[3],
-			   hypercall.arg[4]);
-
-	return ret;
-}
-
-static void free_page_list(struct list_head *pages)
-{
-	struct page *p, *n;
-
-	list_for_each_entry_safe(p, n, pages, lru)
-		__free_page(p);
-
-	INIT_LIST_HEAD(pages);
-}
-
-/*
- * Given an array of items in userspace, return a list of pages
- * containing the data.  If copying fails, either because of memory
- * allocation failure or a problem reading user memory, return an
- * error code; its up to the caller to dispose of any partial list.
- */
-static int gather_array(struct list_head *pagelist,
-			unsigned nelem, size_t size,
-			void __user *data)
-{
-	unsigned pageidx;
-	void *pagedata;
-	int ret;
-
-	if (size > PAGE_SIZE)
-		return 0;
-
-	pageidx = PAGE_SIZE;
-	pagedata = NULL;	/* quiet, gcc */
-	while (nelem--) {
-		if (pageidx > PAGE_SIZE-size) {
-			struct page *page = alloc_page(GFP_KERNEL);
-
-			ret = -ENOMEM;
-			if (page == NULL)
-				goto fail;
-
-			pagedata = page_address(page);
-
-			list_add_tail(&page->lru, pagelist);
-			pageidx = 0;
-		}
-
-		ret = -EFAULT;
-		if (copy_from_user(pagedata + pageidx, data, size))
-			goto fail;
-
-		data += size;
-		pageidx += size;
-	}
-
-	ret = 0;
-
-fail:
-	return ret;
-}
-
-/*
- * Call function "fn" on each element of the array fragmented
- * over a list of pages.
- */
-static int traverse_pages(unsigned nelem, size_t size,
-			  struct list_head *pos,
-			  int (*fn)(void *data, void *state),
-			  void *state)
-{
-	void *pagedata;
-	unsigned pageidx;
-	int ret = 0;
-
-	BUG_ON(size > PAGE_SIZE);
-
-	pageidx = PAGE_SIZE;
-	pagedata = NULL;	/* hush, gcc */
-
-	while (nelem--) {
-		if (pageidx > PAGE_SIZE-size) {
-			struct page *page;
-			pos = pos->next;
-			page = list_entry(pos, struct page, lru);
-			pagedata = page_address(page);
-			pageidx = 0;
-		}
-
-		ret = (*fn)(pagedata + pageidx, state);
-		if (ret)
-			break;
-		pageidx += size;
-	}
-
-	return ret;
-}
-
-struct mmap_mfn_state {
-	unsigned long va;
-	struct vm_area_struct *vma;
-	domid_t domain;
-};
-
-static int mmap_mfn_range(void *data, void *state)
-{
-	struct privcmd_mmap_entry *msg = data;
-	struct mmap_mfn_state *st = state;
-	struct vm_area_struct *vma = st->vma;
-	int rc;
-
-	/* Do not allow range to wrap the address space. */
-	if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
-	    ((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
-		return -EINVAL;
-
-	/* Range chunks must be contiguous in va space. */
-	if ((msg->va != st->va) ||
-	    ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
-		return -EINVAL;
-
-	rc = xen_remap_domain_mfn_range(vma,
-					msg->va & PAGE_MASK,
-					msg->mfn, msg->npages,
-					vma->vm_page_prot,
-					st->domain);
-	if (rc < 0)
-		return rc;
-
-	st->va += msg->npages << PAGE_SHIFT;
-
-	return 0;
-}
-
-static long privcmd_ioctl_mmap(void __user *udata)
-{
-	struct privcmd_mmap mmapcmd;
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
-	int rc;
-	LIST_HEAD(pagelist);
-	struct mmap_mfn_state state;
-
-	if (!xen_initial_domain())
-		return -EPERM;
-
-	if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
-		return -EFAULT;
-
-	rc = gather_array(&pagelist,
-			  mmapcmd.num, sizeof(struct privcmd_mmap_entry),
-			  mmapcmd.entry);
-
-	if (rc || list_empty(&pagelist))
-		goto out;
-
-	down_write(&mm->mmap_sem);
-
-	{
-		struct page *page = list_first_entry(&pagelist,
-						     struct page, lru);
-		struct privcmd_mmap_entry *msg = page_address(page);
-
-		vma = find_vma(mm, msg->va);
-		rc = -EINVAL;
-
-		if (!vma || (msg->va != vma->vm_start) ||
-		    !privcmd_enforce_singleshot_mapping(vma))
-			goto out_up;
-	}
-
-	state.va = vma->vm_start;
-	state.vma = vma;
-	state.domain = mmapcmd.dom;
-
-	rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
-			    &pagelist,
-			    mmap_mfn_range, &state);
-
-
-out_up:
-	up_write(&mm->mmap_sem);
-
-out:
-	free_page_list(&pagelist);
-
-	return rc;
-}
-
-struct mmap_batch_state {
-	domid_t domain;
-	unsigned long va;
-	struct vm_area_struct *vma;
-	int err;
-
-	xen_pfn_t __user *user;
-};
-
-static int mmap_batch_fn(void *data, void *state)
-{
-	xen_pfn_t *mfnp = data;
-	struct mmap_batch_state *st = state;
-
-	if (xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
-				       st->vma->vm_page_prot, st->domain) < 0) {
-		*mfnp |= 0xf0000000U;
-		st->err++;
-	}
-	st->va += PAGE_SIZE;
-
-	return 0;
-}
-
-static int mmap_return_errors(void *data, void *state)
-{
-	xen_pfn_t *mfnp = data;
-	struct mmap_batch_state *st = state;
-
-	return put_user(*mfnp, st->user++);
-}
-
-static struct vm_operations_struct privcmd_vm_ops;
-
-static long privcmd_ioctl_mmap_batch(void __user *udata)
-{
-	int ret;
-	struct privcmd_mmapbatch m;
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma;
-	unsigned long nr_pages;
-	LIST_HEAD(pagelist);
-	struct mmap_batch_state state;
-
-	if (!xen_initial_domain())
-		return -EPERM;
-
-	if (copy_from_user(&m, udata, sizeof(m)))
-		return -EFAULT;
-
-	nr_pages = m.num;
-	if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
-		return -EINVAL;
-
-	ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t),
-			   m.arr);
-
-	if (ret || list_empty(&pagelist))
-		goto out;
-
-	down_write(&mm->mmap_sem);
-
-	vma = find_vma(mm, m.addr);
-	ret = -EINVAL;
-	if (!vma ||
-	    vma->vm_ops != &privcmd_vm_ops ||
-	    (m.addr != vma->vm_start) ||
-	    ((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) ||
-	    !privcmd_enforce_singleshot_mapping(vma)) {
-		up_write(&mm->mmap_sem);
-		goto out;
-	}
-
-	state.domain = m.dom;
-	state.vma = vma;
-	state.va = m.addr;
-	state.err = 0;
-
-	ret = traverse_pages(m.num, sizeof(xen_pfn_t),
-			     &pagelist, mmap_batch_fn, &state);
-
-	up_write(&mm->mmap_sem);
-
-	if (state.err > 0) {
-		state.user = m.arr;
-		ret = traverse_pages(m.num, sizeof(xen_pfn_t),
-			       &pagelist,
-			       mmap_return_errors, &state);
-	}
-
-out:
-	free_page_list(&pagelist);
-
-	return ret;
-}
-
-static long privcmd_ioctl(struct file *file,
-			  unsigned int cmd, unsigned long data)
-{
-	int ret = -ENOSYS;
-	void __user *udata = (void __user *) data;
-
-	switch (cmd) {
-	case IOCTL_PRIVCMD_HYPERCALL:
-		ret = privcmd_ioctl_hypercall(udata);
-		break;
-
-	case IOCTL_PRIVCMD_MMAP:
-		ret = privcmd_ioctl_mmap(udata);
-		break;
-
-	case IOCTL_PRIVCMD_MMAPBATCH:
-		ret = privcmd_ioctl_mmap_batch(udata);
-		break;
-
-	default:
-		ret = -EINVAL;
-		break;
-	}
-
-	return ret;
-}
-
-#ifndef HAVE_ARCH_PRIVCMD_MMAP
-static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
-	printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
-	       vma, vma->vm_start, vma->vm_end,
-	       vmf->pgoff, vmf->virtual_address);
-
-	return VM_FAULT_SIGBUS;
-}
-
-static struct vm_operations_struct privcmd_vm_ops = {
-	.fault = privcmd_fault
-};
-
-static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	/* Unsupported for auto-translate guests. */
-	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return -ENOSYS;
-
-	/* DONTCOPY is essential for Xen because copy_page_range doesn't know
-	 * how to recreate these mappings */
-	vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY | VM_PFNMAP;
-	vma->vm_ops = &privcmd_vm_ops;
-	vma->vm_private_data = NULL;
-
-	return 0;
-}
-
-static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma)
-{
-	return (xchg(&vma->vm_private_data, (void *)1) == NULL);
-}
-#endif
-
-const struct file_operations privcmd_file_ops = {
-	.unlocked_ioctl = privcmd_ioctl,
-	.mmap = privcmd_mmap,
-};
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 1aa389719846..a55fbf9a1519 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -16,6 +16,7 @@
 #include <xen/xen.h>
 
 #include "xenfs.h"
+#include "../privcmd.h"
 
 #include <asm/xen/hypervisor.h>
 
@@ -84,7 +85,7 @@ static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
 		[1] = {},
 		{ "xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR },
 		{ "capabilities", &capabilities_file_ops, S_IRUGO },
-		{ "privcmd", &privcmd_file_ops, S_IRUSR|S_IWUSR },
+		{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
 		{""},
 	};
 	int rc;
diff --git a/drivers/xen/xenfs/xenfs.h b/drivers/xen/xenfs/xenfs.h
index b68aa6200003..5056306e7aa8 100644
--- a/drivers/xen/xenfs/xenfs.h
+++ b/drivers/xen/xenfs/xenfs.h
@@ -2,7 +2,6 @@
 #define _XENFS_XENBUS_H
 
 extern const struct file_operations xenbus_file_ops;
-extern const struct file_operations privcmd_file_ops;
 extern const struct file_operations xsd_kva_file_ops;
 extern const struct file_operations xsd_port_file_ops;