mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 02:56:44 +07:00
a5deabe0e6
When a foreign mapper attempts to map guest frames that are paged out, the mapper receives an ENOENT response and will have to try again while a helper process pages the target frame back in. Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries of mapping calls. Permit subsequent calls to update a sub-range of the VMA, iff nothing is yet mapped in that range. Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only set vma->vm_private_data if the parameters are valid and (if necessary) the pages for the auto_translated_physmap case have been allocated. This prevents subsequent calls from incorrectly entering the 'retry' path when there are no pages allocated etc. Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
626 lines
14 KiB
C
626 lines
14 KiB
C
/******************************************************************************
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* privcmd.c
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*
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* Interface to privileged domain-0 commands.
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*
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* Copyright (c) 2002-2004, K A Fraser, B Dragovic
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*/
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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/uaccess.h>
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#include <linux/swap.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/seq_file.h>
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#include <linux/miscdevice.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include <xen/xen.h>
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#include <xen/privcmd.h>
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#include <xen/interface/xen.h>
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#include <xen/features.h>
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#include <xen/page.h>
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#include <xen/xen-ops.h>
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#include <xen/balloon.h>
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#include "privcmd.h"
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MODULE_LICENSE("GPL");
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#define PRIV_VMA_LOCKED ((void *)1)
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static int privcmd_vma_range_is_mapped(
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struct vm_area_struct *vma,
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unsigned long addr,
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unsigned long nr_pages);
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static long privcmd_ioctl_hypercall(void __user *udata)
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{
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struct privcmd_hypercall hypercall;
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long ret;
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if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
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return -EFAULT;
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ret = privcmd_call(hypercall.op,
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hypercall.arg[0], hypercall.arg[1],
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hypercall.arg[2], hypercall.arg[3],
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hypercall.arg[4]);
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return ret;
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}
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static void free_page_list(struct list_head *pages)
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{
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struct page *p, *n;
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list_for_each_entry_safe(p, n, pages, lru)
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__free_page(p);
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INIT_LIST_HEAD(pages);
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}
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/*
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* Given an array of items in userspace, return a list of pages
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* containing the data. If copying fails, either because of memory
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* allocation failure or a problem reading user memory, return an
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* error code; its up to the caller to dispose of any partial list.
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*/
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static int gather_array(struct list_head *pagelist,
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unsigned nelem, size_t size,
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const void __user *data)
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{
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unsigned pageidx;
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void *pagedata;
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int ret;
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if (size > PAGE_SIZE)
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return 0;
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pageidx = PAGE_SIZE;
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pagedata = NULL; /* quiet, gcc */
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while (nelem--) {
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if (pageidx > PAGE_SIZE-size) {
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struct page *page = alloc_page(GFP_KERNEL);
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ret = -ENOMEM;
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if (page == NULL)
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goto fail;
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pagedata = page_address(page);
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list_add_tail(&page->lru, pagelist);
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pageidx = 0;
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}
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ret = -EFAULT;
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if (copy_from_user(pagedata + pageidx, data, size))
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goto fail;
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data += size;
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pageidx += size;
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}
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ret = 0;
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fail:
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return ret;
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}
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/*
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* Call function "fn" on each element of the array fragmented
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* over a list of pages.
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*/
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static int traverse_pages(unsigned nelem, size_t size,
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struct list_head *pos,
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int (*fn)(void *data, void *state),
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void *state)
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{
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void *pagedata;
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unsigned pageidx;
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int ret = 0;
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BUG_ON(size > PAGE_SIZE);
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pageidx = PAGE_SIZE;
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pagedata = NULL; /* hush, gcc */
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while (nelem--) {
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if (pageidx > PAGE_SIZE-size) {
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struct page *page;
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pos = pos->next;
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page = list_entry(pos, struct page, lru);
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pagedata = page_address(page);
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pageidx = 0;
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}
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ret = (*fn)(pagedata + pageidx, state);
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if (ret)
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break;
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pageidx += size;
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}
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return ret;
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}
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struct mmap_mfn_state {
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unsigned long va;
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struct vm_area_struct *vma;
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domid_t domain;
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};
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static int mmap_mfn_range(void *data, void *state)
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{
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struct privcmd_mmap_entry *msg = data;
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struct mmap_mfn_state *st = state;
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struct vm_area_struct *vma = st->vma;
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int rc;
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/* Do not allow range to wrap the address space. */
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if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
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((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
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return -EINVAL;
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/* Range chunks must be contiguous in va space. */
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if ((msg->va != st->va) ||
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((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
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return -EINVAL;
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rc = xen_remap_domain_mfn_range(vma,
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msg->va & PAGE_MASK,
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msg->mfn, msg->npages,
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vma->vm_page_prot,
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st->domain, NULL);
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if (rc < 0)
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return rc;
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st->va += msg->npages << PAGE_SHIFT;
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return 0;
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}
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static long privcmd_ioctl_mmap(void __user *udata)
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{
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struct privcmd_mmap mmapcmd;
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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int rc;
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LIST_HEAD(pagelist);
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struct mmap_mfn_state state;
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/* We only support privcmd_ioctl_mmap_batch for auto translated. */
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return -ENOSYS;
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if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
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return -EFAULT;
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rc = gather_array(&pagelist,
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mmapcmd.num, sizeof(struct privcmd_mmap_entry),
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mmapcmd.entry);
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if (rc || list_empty(&pagelist))
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goto out;
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down_write(&mm->mmap_sem);
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{
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struct page *page = list_first_entry(&pagelist,
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struct page, lru);
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struct privcmd_mmap_entry *msg = page_address(page);
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vma = find_vma(mm, msg->va);
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rc = -EINVAL;
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if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
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goto out_up;
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vma->vm_private_data = PRIV_VMA_LOCKED;
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}
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state.va = vma->vm_start;
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state.vma = vma;
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state.domain = mmapcmd.dom;
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rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
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&pagelist,
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mmap_mfn_range, &state);
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out_up:
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up_write(&mm->mmap_sem);
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out:
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free_page_list(&pagelist);
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return rc;
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}
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struct mmap_batch_state {
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domid_t domain;
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unsigned long va;
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struct vm_area_struct *vma;
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int index;
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/* A tristate:
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* 0 for no errors
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* 1 if at least one error has happened (and no
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* -ENOENT errors have happened)
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* -ENOENT if at least 1 -ENOENT has happened.
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*/
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int global_error;
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int version;
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/* User-space mfn array to store errors in the second pass for V1. */
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xen_pfn_t __user *user_mfn;
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/* User-space int array to store errors in the second pass for V2. */
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int __user *user_err;
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};
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/* auto translated dom0 note: if domU being created is PV, then mfn is
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* mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP).
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*/
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static int mmap_batch_fn(void *data, void *state)
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{
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xen_pfn_t *mfnp = data;
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struct mmap_batch_state *st = state;
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struct vm_area_struct *vma = st->vma;
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struct page **pages = vma->vm_private_data;
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struct page *cur_page = NULL;
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int ret;
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if (xen_feature(XENFEAT_auto_translated_physmap))
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cur_page = pages[st->index++];
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ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
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st->vma->vm_page_prot, st->domain,
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&cur_page);
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/* Store error code for second pass. */
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if (st->version == 1) {
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if (ret < 0) {
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/*
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* V1 encodes the error codes in the 32bit top nibble of the
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* mfn (with its known limitations vis-a-vis 64 bit callers).
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*/
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*mfnp |= (ret == -ENOENT) ?
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PRIVCMD_MMAPBATCH_PAGED_ERROR :
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PRIVCMD_MMAPBATCH_MFN_ERROR;
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}
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} else { /* st->version == 2 */
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*((int *) mfnp) = ret;
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}
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/* And see if it affects the global_error. */
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if (ret < 0) {
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if (ret == -ENOENT)
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st->global_error = -ENOENT;
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else {
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/* Record that at least one error has happened. */
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if (st->global_error == 0)
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st->global_error = 1;
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}
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}
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st->va += PAGE_SIZE;
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return 0;
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}
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static int mmap_return_errors(void *data, void *state)
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{
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struct mmap_batch_state *st = state;
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if (st->version == 1) {
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xen_pfn_t mfnp = *((xen_pfn_t *) data);
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if (mfnp & PRIVCMD_MMAPBATCH_MFN_ERROR)
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return __put_user(mfnp, st->user_mfn++);
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else
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st->user_mfn++;
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} else { /* st->version == 2 */
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int err = *((int *) data);
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if (err)
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return __put_user(err, st->user_err++);
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else
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st->user_err++;
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}
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return 0;
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}
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/* Allocate pfns that are then mapped with gmfns from foreign domid. Update
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* the vma with the page info to use later.
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* Returns: 0 if success, otherwise -errno
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*/
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static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
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{
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int rc;
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struct page **pages;
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pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
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if (pages == NULL)
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return -ENOMEM;
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rc = alloc_xenballooned_pages(numpgs, pages, 0);
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if (rc != 0) {
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pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
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numpgs, rc);
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kfree(pages);
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return -ENOMEM;
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}
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BUG_ON(vma->vm_private_data != NULL);
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vma->vm_private_data = pages;
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return 0;
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}
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static struct vm_operations_struct privcmd_vm_ops;
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static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
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{
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int ret;
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struct privcmd_mmapbatch_v2 m;
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long nr_pages;
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LIST_HEAD(pagelist);
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struct mmap_batch_state state;
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switch (version) {
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case 1:
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if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
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return -EFAULT;
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/* Returns per-frame error in m.arr. */
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m.err = NULL;
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if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr)))
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return -EFAULT;
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break;
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case 2:
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if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
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return -EFAULT;
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/* Returns per-frame error code in m.err. */
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if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err))))
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return -EFAULT;
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break;
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default:
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return -EINVAL;
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}
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nr_pages = m.num;
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if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
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return -EINVAL;
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ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
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if (ret)
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goto out;
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if (list_empty(&pagelist)) {
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ret = -EINVAL;
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goto out;
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}
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if (version == 2) {
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/* Zero error array now to only copy back actual errors. */
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if (clear_user(m.err, sizeof(int) * m.num)) {
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ret = -EFAULT;
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goto out;
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}
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}
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down_write(&mm->mmap_sem);
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vma = find_vma(mm, m.addr);
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if (!vma ||
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vma->vm_ops != &privcmd_vm_ops) {
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ret = -EINVAL;
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goto out_unlock;
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}
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/*
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* Caller must either:
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*
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* Map the whole VMA range, which will also allocate all the
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* pages required for the auto_translated_physmap case.
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*
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* Or
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*
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* Map unmapped holes left from a previous map attempt (e.g.,
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* because those foreign frames were previously paged out).
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*/
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if (vma->vm_private_data == NULL) {
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if (m.addr != vma->vm_start ||
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m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
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ret = -EINVAL;
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goto out_unlock;
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}
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if (xen_feature(XENFEAT_auto_translated_physmap)) {
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ret = alloc_empty_pages(vma, m.num);
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if (ret < 0)
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goto out_unlock;
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} else
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vma->vm_private_data = PRIV_VMA_LOCKED;
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} else {
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if (m.addr < vma->vm_start ||
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m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
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ret = -EINVAL;
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goto out_unlock;
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}
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if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
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ret = -EINVAL;
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goto out_unlock;
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}
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}
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state.domain = m.dom;
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state.vma = vma;
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state.va = m.addr;
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state.index = 0;
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state.global_error = 0;
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state.version = version;
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/* mmap_batch_fn guarantees ret == 0 */
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BUG_ON(traverse_pages(m.num, sizeof(xen_pfn_t),
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&pagelist, mmap_batch_fn, &state));
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up_write(&mm->mmap_sem);
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if (state.global_error) {
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/* Write back errors in second pass. */
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state.user_mfn = (xen_pfn_t *)m.arr;
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state.user_err = m.err;
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ret = traverse_pages(m.num, sizeof(xen_pfn_t),
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&pagelist, mmap_return_errors, &state);
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} else
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ret = 0;
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/* If we have not had any EFAULT-like global errors then set the global
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* error to -ENOENT if necessary. */
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if ((ret == 0) && (state.global_error == -ENOENT))
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ret = -ENOENT;
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out:
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free_page_list(&pagelist);
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return ret;
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out_unlock:
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up_write(&mm->mmap_sem);
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goto out;
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}
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static long privcmd_ioctl(struct file *file,
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unsigned int cmd, unsigned long data)
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{
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int ret = -ENOSYS;
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void __user *udata = (void __user *) data;
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switch (cmd) {
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case IOCTL_PRIVCMD_HYPERCALL:
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ret = privcmd_ioctl_hypercall(udata);
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break;
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case IOCTL_PRIVCMD_MMAP:
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ret = privcmd_ioctl_mmap(udata);
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break;
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case IOCTL_PRIVCMD_MMAPBATCH:
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ret = privcmd_ioctl_mmap_batch(udata, 1);
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break;
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case IOCTL_PRIVCMD_MMAPBATCH_V2:
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ret = privcmd_ioctl_mmap_batch(udata, 2);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
|
|
|
|
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;
|
|
|
|
if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
|
|
return;
|
|
|
|
xen_unmap_domain_mfn_range(vma, numpgs, pages);
|
|
free_xenballooned_pages(numpgs, pages);
|
|
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);
|