| /****************************************************************************** |
| * privcmd.c |
| * |
| * Interface to privileged domain-0 commands. |
| * |
| * Copyright (c) 2002-2004, K A Fraser, B Dragovic |
| */ |
| |
| #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.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 <linux/miscdevice.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> |
| #include <xen/balloon.h> |
| |
| #include "privcmd.h" |
| |
| MODULE_LICENSE("GPL"); |
| |
| #define PRIV_VMA_LOCKED ((void *)1) |
| |
| static int privcmd_vma_range_is_mapped( |
| struct vm_area_struct *vma, |
| unsigned long addr, |
| unsigned long nr_pages); |
| |
| 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, |
| const 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, NULL); |
| 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; |
| |
| /* We only support privcmd_ioctl_mmap_batch for auto translated. */ |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| return -ENOSYS; |
| |
| 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) || vma->vm_private_data) |
| goto out_up; |
| vma->vm_private_data = PRIV_VMA_LOCKED; |
| } |
| |
| 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 index; |
| /* A tristate: |
| * 0 for no errors |
| * 1 if at least one error has happened (and no |
| * -ENOENT errors have happened) |
| * -ENOENT if at least 1 -ENOENT has happened. |
| */ |
| int global_error; |
| int version; |
| |
| /* User-space mfn array to store errors in the second pass for V1. */ |
| xen_pfn_t __user *user_mfn; |
| /* User-space int array to store errors in the second pass for V2. */ |
| int __user *user_err; |
| }; |
| |
| /* auto translated dom0 note: if domU being created is PV, then mfn is |
| * mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP). |
| */ |
| static int mmap_batch_fn(void *data, void *state) |
| { |
| xen_pfn_t *mfnp = data; |
| struct mmap_batch_state *st = state; |
| struct vm_area_struct *vma = st->vma; |
| struct page **pages = vma->vm_private_data; |
| struct page *cur_page = NULL; |
| int ret; |
| |
| if (xen_feature(XENFEAT_auto_translated_physmap)) |
| cur_page = pages[st->index++]; |
| |
| ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1, |
| st->vma->vm_page_prot, st->domain, |
| &cur_page); |
| |
| /* Store error code for second pass. */ |
| if (st->version == 1) { |
| if (ret < 0) { |
| /* |
| * V1 encodes the error codes in the 32bit top nibble of the |
| * mfn (with its known limitations vis-a-vis 64 bit callers). |
| */ |
| *mfnp |= (ret == -ENOENT) ? |
| PRIVCMD_MMAPBATCH_PAGED_ERROR : |
| PRIVCMD_MMAPBATCH_MFN_ERROR; |
| } |
| } else { /* st->version == 2 */ |
| *((int *) mfnp) = ret; |
| } |
| |
| /* And see if it affects the global_error. */ |
| if (ret < 0) { |
| if (ret == -ENOENT) |
| st->global_error = -ENOENT; |
| else { |
| /* Record that at least one error has happened. */ |
| if (st->global_error == 0) |
| st->global_error = 1; |
| } |
| } |
| st->va += PAGE_SIZE; |
| |
| return 0; |
| } |
| |
| static int mmap_return_errors(void *data, void *state) |
| { |
| struct mmap_batch_state *st = state; |
| |
| if (st->version == 1) { |
| xen_pfn_t mfnp = *((xen_pfn_t *) data); |
| if (mfnp & PRIVCMD_MMAPBATCH_MFN_ERROR) |
| return __put_user(mfnp, st->user_mfn++); |
| else |
| st->user_mfn++; |
| } else { /* st->version == 2 */ |
| int err = *((int *) data); |
| if (err) |
| return __put_user(err, st->user_err++); |
| else |
| st->user_err++; |
| } |
| |
| return 0; |
| } |
| |
| /* Allocate pfns that are then mapped with gmfns from foreign domid. Update |
| * the vma with the page info to use later. |
| * Returns: 0 if success, otherwise -errno |
| */ |
| static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs) |
| { |
| int rc; |
| struct page **pages; |
| |
| pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL); |
| if (pages == NULL) |
| return -ENOMEM; |
| |
| rc = alloc_xenballooned_pages(numpgs, pages, 0); |
| if (rc != 0) { |
| pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__, |
| numpgs, rc); |
| kfree(pages); |
| return -ENOMEM; |
| } |
| BUG_ON(vma->vm_private_data != NULL); |
| vma->vm_private_data = pages; |
| |
| return 0; |
| } |
| |
| static struct vm_operations_struct privcmd_vm_ops; |
| |
| static long privcmd_ioctl_mmap_batch(void __user *udata, int version) |
| { |
| int ret; |
| struct privcmd_mmapbatch_v2 m; |
| struct mm_struct *mm = current->mm; |
| struct vm_area_struct *vma; |
| unsigned long nr_pages; |
| LIST_HEAD(pagelist); |
| struct mmap_batch_state state; |
| |
| switch (version) { |
| case 1: |
| if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch))) |
| return -EFAULT; |
| /* Returns per-frame error in m.arr. */ |
| m.err = NULL; |
| if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr))) |
| return -EFAULT; |
| break; |
| case 2: |
| if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2))) |
| return -EFAULT; |
| /* Returns per-frame error code in m.err. */ |
| if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err)))) |
| return -EFAULT; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| 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) |
| goto out; |
| if (list_empty(&pagelist)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (version == 2) { |
| /* Zero error array now to only copy back actual errors. */ |
| if (clear_user(m.err, sizeof(int) * m.num)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| } |
| |
| down_write(&mm->mmap_sem); |
| |
| vma = find_vma(mm, m.addr); |
| if (!vma || |
| vma->vm_ops != &privcmd_vm_ops) { |
| ret = -EINVAL; |
| goto out_unlock; |
| } |
| |
| /* |
| * Caller must either: |
| * |
| * Map the whole VMA range, which will also allocate all the |
| * pages required for the auto_translated_physmap case. |
| * |
| * Or |
| * |
| * Map unmapped holes left from a previous map attempt (e.g., |
| * because those foreign frames were previously paged out). |
| */ |
| if (vma->vm_private_data == NULL) { |
| if (m.addr != vma->vm_start || |
| m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) { |
| ret = -EINVAL; |
| goto out_unlock; |
| } |
| if (xen_feature(XENFEAT_auto_translated_physmap)) { |
| ret = alloc_empty_pages(vma, m.num); |
| if (ret < 0) |
| goto out_unlock; |
| } else |
| vma->vm_private_data = PRIV_VMA_LOCKED; |
| } else { |
| if (m.addr < vma->vm_start || |
| m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) { |
| ret = -EINVAL; |
| goto out_unlock; |
| } |
| if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) { |
| ret = -EINVAL; |
| goto out_unlock; |
| } |
| } |
| |
| state.domain = m.dom; |
| state.vma = vma; |
| state.va = m.addr; |
| state.index = 0; |
| state.global_error = 0; |
| state.version = version; |
| |
| /* mmap_batch_fn guarantees ret == 0 */ |
| BUG_ON(traverse_pages(m.num, sizeof(xen_pfn_t), |
| &pagelist, mmap_batch_fn, &state)); |
| |
| up_write(&mm->mmap_sem); |
| |
| if (state.global_error) { |
| /* Write back errors in second pass. */ |
| state.user_mfn = (xen_pfn_t *)m.arr; |
| state.user_err = m.err; |
| ret = traverse_pages(m.num, sizeof(xen_pfn_t), |
| &pagelist, mmap_return_errors, &state); |
| } else |
| ret = 0; |
| |
| /* If we have not had any EFAULT-like global errors then set the global |
| * error to -ENOENT if necessary. */ |
| if ((ret == 0) && (state.global_error == -ENOENT)) |
| ret = -ENOENT; |
| |
| out: |
| free_page_list(&pagelist); |
| return ret; |
| |
| out_unlock: |
| up_write(&mm->mmap_sem); |
| goto out; |
| } |
| |
| 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, 1); |
| break; |
| |
| case IOCTL_PRIVCMD_MMAPBATCH_V2: |
| ret = privcmd_ioctl_mmap_batch(udata, 2); |
| break; |
| |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static void privcmd_close(struct vm_area_struct *vma) |
| { |
| struct page **pages = vma->vm_private_data; |
| int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
| int rc; |
| |
| if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages) |
| return; |
| |
| rc = xen_unmap_domain_mfn_range(vma, numpgs, pages); |
| if (rc == 0) |
| free_xenballooned_pages(numpgs, pages); |
| else |
| pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n", |
| numpgs, rc); |
| kfree(pages); |
| } |
| |
| 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 = { |
| .close = privcmd_close, |
| .fault = privcmd_fault |
| }; |
| |
| static int privcmd_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| /* DONTCOPY is essential for Xen because copy_page_range doesn't know |
| * how to recreate these mappings */ |
| vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTCOPY | |
| VM_DONTEXPAND | VM_DONTDUMP; |
| vma->vm_ops = &privcmd_vm_ops; |
| vma->vm_private_data = NULL; |
| |
| return 0; |
| } |
| |
| /* |
| * For MMAPBATCH*. This allows asserting the singleshot mapping |
| * on a per pfn/pte basis. Mapping calls that fail with ENOENT |
| * can be then retried until success. |
| */ |
| static int is_mapped_fn(pte_t *pte, struct page *pmd_page, |
| unsigned long addr, void *data) |
| { |
| return pte_none(*pte) ? 0 : -EBUSY; |
| } |
| |
| static int privcmd_vma_range_is_mapped( |
| struct vm_area_struct *vma, |
| unsigned long addr, |
| unsigned long nr_pages) |
| { |
| return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT, |
| is_mapped_fn, NULL) != 0; |
| } |
| |
| const struct file_operations xen_privcmd_fops = { |
| .owner = THIS_MODULE, |
| .unlocked_ioctl = privcmd_ioctl, |
| .mmap = privcmd_mmap, |
| }; |
| EXPORT_SYMBOL_GPL(xen_privcmd_fops); |
| |
| static struct miscdevice privcmd_dev = { |
| .minor = MISC_DYNAMIC_MINOR, |
| .name = "xen/privcmd", |
| .fops = &xen_privcmd_fops, |
| }; |
| |
| static int __init privcmd_init(void) |
| { |
| int err; |
| |
| if (!xen_domain()) |
| return -ENODEV; |
| |
| err = misc_register(&privcmd_dev); |
| if (err != 0) { |
| pr_err("Could not register Xen privcmd device\n"); |
| return err; |
| } |
| return 0; |
| } |
| |
| static void __exit privcmd_exit(void) |
| { |
| misc_deregister(&privcmd_dev); |
| } |
| |
| module_init(privcmd_init); |
| module_exit(privcmd_exit); |