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5a4fe7c41b
As pointed out with the simplification of the VFIO_IOMMU_NOTIFY_DMA_UNMAP notifier [1], the length parameter was never used to check against the pinned pages. Let's correct that, and see if a page is within the affected range instead of simply the first page of the range. [1] https://lore.kernel.org/kvm/20220720170457.39cda0d0.alex.williamson@redhat.com/ Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20220728204914.2420989-2-farman@linux.ibm.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
928 lines
23 KiB
C
928 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* channel program interfaces
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*
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* Copyright IBM Corp. 2017
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*
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* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
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* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
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*/
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#include <linux/ratelimit.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/highmem.h>
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#include <linux/iommu.h>
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#include <linux/vfio.h>
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#include <asm/idals.h>
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#include "vfio_ccw_cp.h"
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#include "vfio_ccw_private.h"
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struct page_array {
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/* Array that stores pages need to pin. */
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dma_addr_t *pa_iova;
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/* Array that receives the pinned pages. */
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struct page **pa_page;
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/* Number of pages pinned from @pa_iova. */
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int pa_nr;
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};
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struct ccwchain {
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struct list_head next;
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struct ccw1 *ch_ccw;
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/* Guest physical address of the current chain. */
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u64 ch_iova;
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/* Count of the valid ccws in chain. */
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int ch_len;
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/* Pinned PAGEs for the original data. */
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struct page_array *ch_pa;
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};
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/*
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* page_array_alloc() - alloc memory for page array
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* @pa: page_array on which to perform the operation
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* @iova: target guest physical address
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* @len: number of bytes that should be pinned from @iova
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*
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* Attempt to allocate memory for page array.
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*
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* Usage of page_array:
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* We expect (pa_nr == 0) and (pa_iova == NULL), any field in
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* this structure will be filled in by this function.
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*
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* Returns:
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* 0 if page array is allocated
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* -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova is not NULL
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* -ENOMEM if alloc failed
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*/
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static int page_array_alloc(struct page_array *pa, u64 iova, unsigned int len)
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{
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int i;
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if (pa->pa_nr || pa->pa_iova)
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return -EINVAL;
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pa->pa_nr = ((iova & ~PAGE_MASK) + len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
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if (!pa->pa_nr)
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return -EINVAL;
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pa->pa_iova = kcalloc(pa->pa_nr,
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sizeof(*pa->pa_iova) + sizeof(*pa->pa_page),
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GFP_KERNEL);
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if (unlikely(!pa->pa_iova)) {
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pa->pa_nr = 0;
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return -ENOMEM;
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}
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pa->pa_page = (struct page **)&pa->pa_iova[pa->pa_nr];
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pa->pa_iova[0] = iova;
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pa->pa_page[0] = NULL;
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for (i = 1; i < pa->pa_nr; i++) {
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pa->pa_iova[i] = pa->pa_iova[i - 1] + PAGE_SIZE;
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pa->pa_page[i] = NULL;
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}
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return 0;
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}
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/*
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* page_array_unpin() - Unpin user pages in memory
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* @pa: page_array on which to perform the operation
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* @vdev: the vfio device to perform the operation
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* @pa_nr: number of user pages to unpin
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*
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* Only unpin if any pages were pinned to begin with, i.e. pa_nr > 0,
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* otherwise only clear pa->pa_nr
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*/
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static void page_array_unpin(struct page_array *pa,
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struct vfio_device *vdev, int pa_nr)
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{
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int unpinned = 0, npage = 1;
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while (unpinned < pa_nr) {
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dma_addr_t *first = &pa->pa_iova[unpinned];
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dma_addr_t *last = &first[npage];
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if (unpinned + npage < pa_nr &&
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*first + npage * PAGE_SIZE == *last) {
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npage++;
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continue;
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}
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vfio_unpin_pages(vdev, *first, npage);
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unpinned += npage;
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npage = 1;
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}
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pa->pa_nr = 0;
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}
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/*
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* page_array_pin() - Pin user pages in memory
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* @pa: page_array on which to perform the operation
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* @mdev: the mediated device to perform pin operations
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*
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* Returns number of pages pinned upon success.
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* If the pin request partially succeeds, or fails completely,
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* all pages are left unpinned and a negative error value is returned.
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*/
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static int page_array_pin(struct page_array *pa, struct vfio_device *vdev)
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{
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int pinned = 0, npage = 1;
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int ret = 0;
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while (pinned < pa->pa_nr) {
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dma_addr_t *first = &pa->pa_iova[pinned];
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dma_addr_t *last = &first[npage];
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if (pinned + npage < pa->pa_nr &&
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*first + npage * PAGE_SIZE == *last) {
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npage++;
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continue;
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}
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ret = vfio_pin_pages(vdev, *first, npage,
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IOMMU_READ | IOMMU_WRITE,
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&pa->pa_page[pinned]);
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if (ret < 0) {
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goto err_out;
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} else if (ret > 0 && ret != npage) {
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pinned += ret;
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ret = -EINVAL;
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goto err_out;
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}
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pinned += npage;
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npage = 1;
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}
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return ret;
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err_out:
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page_array_unpin(pa, vdev, pinned);
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return ret;
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}
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/* Unpin the pages before releasing the memory. */
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static void page_array_unpin_free(struct page_array *pa, struct vfio_device *vdev)
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{
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page_array_unpin(pa, vdev, pa->pa_nr);
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kfree(pa->pa_iova);
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}
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static bool page_array_iova_pinned(struct page_array *pa, u64 iova, u64 length)
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{
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u64 iova_pfn_start = iova >> PAGE_SHIFT;
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u64 iova_pfn_end = (iova + length - 1) >> PAGE_SHIFT;
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u64 pfn;
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int i;
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for (i = 0; i < pa->pa_nr; i++) {
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pfn = pa->pa_iova[i] >> PAGE_SHIFT;
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if (pfn >= iova_pfn_start && pfn <= iova_pfn_end)
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return true;
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}
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return false;
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}
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/* Create the list of IDAL words for a page_array. */
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static inline void page_array_idal_create_words(struct page_array *pa,
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unsigned long *idaws)
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{
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int i;
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/*
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* Idal words (execept the first one) rely on the memory being 4k
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* aligned. If a user virtual address is 4K aligned, then it's
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* corresponding kernel physical address will also be 4K aligned. Thus
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* there will be no problem here to simply use the phys to create an
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* idaw.
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*/
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for (i = 0; i < pa->pa_nr; i++)
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idaws[i] = page_to_phys(pa->pa_page[i]);
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/* Adjust the first IDAW, since it may not start on a page boundary */
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idaws[0] += pa->pa_iova[0] & (PAGE_SIZE - 1);
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}
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static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
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{
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struct ccw0 ccw0;
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struct ccw1 *pccw1 = source;
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int i;
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for (i = 0; i < len; i++) {
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ccw0 = *(struct ccw0 *)pccw1;
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if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
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pccw1->cmd_code = CCW_CMD_TIC;
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pccw1->flags = 0;
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pccw1->count = 0;
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} else {
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pccw1->cmd_code = ccw0.cmd_code;
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pccw1->flags = ccw0.flags;
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pccw1->count = ccw0.count;
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}
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pccw1->cda = ccw0.cda;
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pccw1++;
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}
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}
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/*
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* Within the domain (@mdev), copy @n bytes from a guest physical
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* address (@iova) to a host physical address (@to).
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*/
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static long copy_from_iova(struct vfio_device *vdev, void *to, u64 iova,
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unsigned long n)
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{
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struct page_array pa = {0};
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int i, ret;
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unsigned long l, m;
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ret = page_array_alloc(&pa, iova, n);
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if (ret < 0)
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return ret;
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ret = page_array_pin(&pa, vdev);
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if (ret < 0) {
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page_array_unpin_free(&pa, vdev);
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return ret;
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}
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l = n;
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for (i = 0; i < pa.pa_nr; i++) {
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void *from = kmap_local_page(pa.pa_page[i]);
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m = PAGE_SIZE;
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if (i == 0) {
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from += iova & (PAGE_SIZE - 1);
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m -= iova & (PAGE_SIZE - 1);
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}
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m = min(l, m);
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memcpy(to + (n - l), from, m);
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kunmap_local(from);
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l -= m;
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if (l == 0)
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break;
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}
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page_array_unpin_free(&pa, vdev);
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return l;
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}
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/*
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* Helpers to operate ccwchain.
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*/
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#define ccw_is_read(_ccw) (((_ccw)->cmd_code & 0x03) == 0x02)
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#define ccw_is_read_backward(_ccw) (((_ccw)->cmd_code & 0x0F) == 0x0C)
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#define ccw_is_sense(_ccw) (((_ccw)->cmd_code & 0x0F) == CCW_CMD_BASIC_SENSE)
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#define ccw_is_noop(_ccw) ((_ccw)->cmd_code == CCW_CMD_NOOP)
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#define ccw_is_tic(_ccw) ((_ccw)->cmd_code == CCW_CMD_TIC)
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#define ccw_is_idal(_ccw) ((_ccw)->flags & CCW_FLAG_IDA)
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#define ccw_is_skip(_ccw) ((_ccw)->flags & CCW_FLAG_SKIP)
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#define ccw_is_chain(_ccw) ((_ccw)->flags & (CCW_FLAG_CC | CCW_FLAG_DC))
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/*
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* ccw_does_data_transfer()
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*
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* Determine whether a CCW will move any data, such that the guest pages
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* would need to be pinned before performing the I/O.
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*
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* Returns 1 if yes, 0 if no.
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*/
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static inline int ccw_does_data_transfer(struct ccw1 *ccw)
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{
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/* If the count field is zero, then no data will be transferred */
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if (ccw->count == 0)
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return 0;
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/* If the command is a NOP, then no data will be transferred */
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if (ccw_is_noop(ccw))
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return 0;
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/* If the skip flag is off, then data will be transferred */
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if (!ccw_is_skip(ccw))
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return 1;
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/*
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* If the skip flag is on, it is only meaningful if the command
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* code is a read, read backward, sense, or sense ID. In those
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* cases, no data will be transferred.
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*/
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if (ccw_is_read(ccw) || ccw_is_read_backward(ccw))
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return 0;
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if (ccw_is_sense(ccw))
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return 0;
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/* The skip flag is on, but it is ignored for this command code. */
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return 1;
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}
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/*
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* is_cpa_within_range()
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*
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* @cpa: channel program address being questioned
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* @head: address of the beginning of a CCW chain
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* @len: number of CCWs within the chain
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*
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* Determine whether the address of a CCW (whether a new chain,
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* or the target of a TIC) falls within a range (including the end points).
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*
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* Returns 1 if yes, 0 if no.
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*/
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static inline int is_cpa_within_range(u32 cpa, u32 head, int len)
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{
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u32 tail = head + (len - 1) * sizeof(struct ccw1);
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return (head <= cpa && cpa <= tail);
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}
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static inline int is_tic_within_range(struct ccw1 *ccw, u32 head, int len)
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{
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if (!ccw_is_tic(ccw))
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return 0;
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return is_cpa_within_range(ccw->cda, head, len);
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}
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static struct ccwchain *ccwchain_alloc(struct channel_program *cp, int len)
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{
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struct ccwchain *chain;
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void *data;
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size_t size;
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/* Make ccw address aligned to 8. */
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size = ((sizeof(*chain) + 7L) & -8L) +
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sizeof(*chain->ch_ccw) * len +
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sizeof(*chain->ch_pa) * len;
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chain = kzalloc(size, GFP_DMA | GFP_KERNEL);
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if (!chain)
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return NULL;
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data = (u8 *)chain + ((sizeof(*chain) + 7L) & -8L);
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chain->ch_ccw = (struct ccw1 *)data;
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data = (u8 *)(chain->ch_ccw) + sizeof(*chain->ch_ccw) * len;
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chain->ch_pa = (struct page_array *)data;
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chain->ch_len = len;
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list_add_tail(&chain->next, &cp->ccwchain_list);
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return chain;
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}
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static void ccwchain_free(struct ccwchain *chain)
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{
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list_del(&chain->next);
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kfree(chain);
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}
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/* Free resource for a ccw that allocated memory for its cda. */
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static void ccwchain_cda_free(struct ccwchain *chain, int idx)
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{
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struct ccw1 *ccw = chain->ch_ccw + idx;
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if (ccw_is_tic(ccw))
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return;
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kfree((void *)(u64)ccw->cda);
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}
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/**
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* ccwchain_calc_length - calculate the length of the ccw chain.
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* @iova: guest physical address of the target ccw chain
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* @cp: channel_program on which to perform the operation
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*
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* This is the chain length not considering any TICs.
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* You need to do a new round for each TIC target.
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*
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* The program is also validated for absence of not yet supported
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* indirect data addressing scenarios.
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*
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* Returns: the length of the ccw chain or -errno.
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*/
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static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
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{
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struct ccw1 *ccw = cp->guest_cp;
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int cnt = 0;
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do {
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cnt++;
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/*
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* As we don't want to fail direct addressing even if the
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* orb specified one of the unsupported formats, we defer
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* checking for IDAWs in unsupported formats to here.
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*/
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if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw))
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return -EOPNOTSUPP;
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/*
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* We want to keep counting if the current CCW has the
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* command-chaining flag enabled, or if it is a TIC CCW
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* that loops back into the current chain. The latter
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* is used for device orientation, where the CCW PRIOR to
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* the TIC can either jump to the TIC or a CCW immediately
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* after the TIC, depending on the results of its operation.
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*/
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if (!ccw_is_chain(ccw) && !is_tic_within_range(ccw, iova, cnt))
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break;
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ccw++;
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} while (cnt < CCWCHAIN_LEN_MAX + 1);
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if (cnt == CCWCHAIN_LEN_MAX + 1)
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cnt = -EINVAL;
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return cnt;
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}
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static int tic_target_chain_exists(struct ccw1 *tic, struct channel_program *cp)
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{
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struct ccwchain *chain;
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u32 ccw_head;
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list_for_each_entry(chain, &cp->ccwchain_list, next) {
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ccw_head = chain->ch_iova;
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if (is_cpa_within_range(tic->cda, ccw_head, chain->ch_len))
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return 1;
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}
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return 0;
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}
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static int ccwchain_loop_tic(struct ccwchain *chain,
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struct channel_program *cp);
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static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
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{
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struct vfio_device *vdev =
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&container_of(cp, struct vfio_ccw_private, cp)->vdev;
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struct ccwchain *chain;
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int len, ret;
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/* Copy 2K (the most we support today) of possible CCWs */
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len = copy_from_iova(vdev, cp->guest_cp, cda,
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CCWCHAIN_LEN_MAX * sizeof(struct ccw1));
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if (len)
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return len;
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/* Convert any Format-0 CCWs to Format-1 */
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if (!cp->orb.cmd.fmt)
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convert_ccw0_to_ccw1(cp->guest_cp, CCWCHAIN_LEN_MAX);
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/* Count the CCWs in the current chain */
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len = ccwchain_calc_length(cda, cp);
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if (len < 0)
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return len;
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/* Need alloc a new chain for this one. */
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chain = ccwchain_alloc(cp, len);
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if (!chain)
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return -ENOMEM;
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chain->ch_iova = cda;
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/* Copy the actual CCWs into the new chain */
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memcpy(chain->ch_ccw, cp->guest_cp, len * sizeof(struct ccw1));
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|
|
/* Loop for tics on this new chain. */
|
|
ret = ccwchain_loop_tic(chain, cp);
|
|
|
|
if (ret)
|
|
ccwchain_free(chain);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Loop for TICs. */
|
|
static int ccwchain_loop_tic(struct ccwchain *chain, struct channel_program *cp)
|
|
{
|
|
struct ccw1 *tic;
|
|
int i, ret;
|
|
|
|
for (i = 0; i < chain->ch_len; i++) {
|
|
tic = chain->ch_ccw + i;
|
|
|
|
if (!ccw_is_tic(tic))
|
|
continue;
|
|
|
|
/* May transfer to an existing chain. */
|
|
if (tic_target_chain_exists(tic, cp))
|
|
continue;
|
|
|
|
/* Build a ccwchain for the next segment */
|
|
ret = ccwchain_handle_ccw(tic->cda, cp);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ccwchain_fetch_tic(struct ccwchain *chain,
|
|
int idx,
|
|
struct channel_program *cp)
|
|
{
|
|
struct ccw1 *ccw = chain->ch_ccw + idx;
|
|
struct ccwchain *iter;
|
|
u32 ccw_head;
|
|
|
|
list_for_each_entry(iter, &cp->ccwchain_list, next) {
|
|
ccw_head = iter->ch_iova;
|
|
if (is_cpa_within_range(ccw->cda, ccw_head, iter->ch_len)) {
|
|
ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) +
|
|
(ccw->cda - ccw_head));
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return -EFAULT;
|
|
}
|
|
|
|
static int ccwchain_fetch_direct(struct ccwchain *chain,
|
|
int idx,
|
|
struct channel_program *cp)
|
|
{
|
|
struct vfio_device *vdev =
|
|
&container_of(cp, struct vfio_ccw_private, cp)->vdev;
|
|
struct ccw1 *ccw;
|
|
struct page_array *pa;
|
|
u64 iova;
|
|
unsigned long *idaws;
|
|
int ret;
|
|
int bytes = 1;
|
|
int idaw_nr, idal_len;
|
|
int i;
|
|
|
|
ccw = chain->ch_ccw + idx;
|
|
|
|
if (ccw->count)
|
|
bytes = ccw->count;
|
|
|
|
/* Calculate size of IDAL */
|
|
if (ccw_is_idal(ccw)) {
|
|
/* Read first IDAW to see if it's 4K-aligned or not. */
|
|
/* All subsequent IDAws will be 4K-aligned. */
|
|
ret = copy_from_iova(vdev, &iova, ccw->cda, sizeof(iova));
|
|
if (ret)
|
|
return ret;
|
|
} else {
|
|
iova = ccw->cda;
|
|
}
|
|
idaw_nr = idal_nr_words((void *)iova, bytes);
|
|
idal_len = idaw_nr * sizeof(*idaws);
|
|
|
|
/* Allocate an IDAL from host storage */
|
|
idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
|
|
if (!idaws) {
|
|
ret = -ENOMEM;
|
|
goto out_init;
|
|
}
|
|
|
|
/*
|
|
* Allocate an array of pages to pin/translate.
|
|
* The number of pages is actually the count of the idaws
|
|
* required for the data transfer, since we only only support
|
|
* 4K IDAWs today.
|
|
*/
|
|
pa = chain->ch_pa + idx;
|
|
ret = page_array_alloc(pa, iova, bytes);
|
|
if (ret < 0)
|
|
goto out_free_idaws;
|
|
|
|
if (ccw_is_idal(ccw)) {
|
|
/* Copy guest IDAL into host IDAL */
|
|
ret = copy_from_iova(vdev, idaws, ccw->cda, idal_len);
|
|
if (ret)
|
|
goto out_unpin;
|
|
|
|
/*
|
|
* Copy guest IDAWs into page_array, in case the memory they
|
|
* occupy is not contiguous.
|
|
*/
|
|
for (i = 0; i < idaw_nr; i++)
|
|
pa->pa_iova[i] = idaws[i];
|
|
} else {
|
|
/*
|
|
* No action is required here; the iova addresses in page_array
|
|
* were initialized sequentially in page_array_alloc() beginning
|
|
* with the contents of ccw->cda.
|
|
*/
|
|
}
|
|
|
|
if (ccw_does_data_transfer(ccw)) {
|
|
ret = page_array_pin(pa, vdev);
|
|
if (ret < 0)
|
|
goto out_unpin;
|
|
} else {
|
|
pa->pa_nr = 0;
|
|
}
|
|
|
|
ccw->cda = (__u32) virt_to_phys(idaws);
|
|
ccw->flags |= CCW_FLAG_IDA;
|
|
|
|
/* Populate the IDAL with pinned/translated addresses from page */
|
|
page_array_idal_create_words(pa, idaws);
|
|
|
|
return 0;
|
|
|
|
out_unpin:
|
|
page_array_unpin_free(pa, vdev);
|
|
out_free_idaws:
|
|
kfree(idaws);
|
|
out_init:
|
|
ccw->cda = 0;
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Fetch one ccw.
|
|
* To reduce memory copy, we'll pin the cda page in memory,
|
|
* and to get rid of the cda 2G limitiaion of ccw1, we'll translate
|
|
* direct ccws to idal ccws.
|
|
*/
|
|
static int ccwchain_fetch_one(struct ccwchain *chain,
|
|
int idx,
|
|
struct channel_program *cp)
|
|
{
|
|
struct ccw1 *ccw = chain->ch_ccw + idx;
|
|
|
|
if (ccw_is_tic(ccw))
|
|
return ccwchain_fetch_tic(chain, idx, cp);
|
|
|
|
return ccwchain_fetch_direct(chain, idx, cp);
|
|
}
|
|
|
|
/**
|
|
* cp_init() - allocate ccwchains for a channel program.
|
|
* @cp: channel_program on which to perform the operation
|
|
* @mdev: the mediated device to perform pin/unpin operations
|
|
* @orb: control block for the channel program from the guest
|
|
*
|
|
* This creates one or more ccwchain(s), and copies the raw data of
|
|
* the target channel program from @orb->cmd.iova to the new ccwchain(s).
|
|
*
|
|
* Limitations:
|
|
* 1. Supports idal(c64) ccw chaining.
|
|
* 2. Supports 4k idaw.
|
|
*
|
|
* Returns:
|
|
* %0 on success and a negative error value on failure.
|
|
*/
|
|
int cp_init(struct channel_program *cp, union orb *orb)
|
|
{
|
|
struct vfio_device *vdev =
|
|
&container_of(cp, struct vfio_ccw_private, cp)->vdev;
|
|
/* custom ratelimit used to avoid flood during guest IPL */
|
|
static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1);
|
|
int ret;
|
|
|
|
/* this is an error in the caller */
|
|
if (cp->initialized)
|
|
return -EBUSY;
|
|
|
|
/*
|
|
* We only support prefetching the channel program. We assume all channel
|
|
* programs executed by supported guests likewise support prefetching.
|
|
* Executing a channel program that does not specify prefetching will
|
|
* typically not cause an error, but a warning is issued to help identify
|
|
* the problem if something does break.
|
|
*/
|
|
if (!orb->cmd.pfch && __ratelimit(&ratelimit_state))
|
|
dev_warn(
|
|
vdev->dev,
|
|
"Prefetching channel program even though prefetch not specified in ORB");
|
|
|
|
INIT_LIST_HEAD(&cp->ccwchain_list);
|
|
memcpy(&cp->orb, orb, sizeof(*orb));
|
|
|
|
/* Build a ccwchain for the first CCW segment */
|
|
ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
|
|
|
|
if (!ret) {
|
|
cp->initialized = true;
|
|
|
|
/* It is safe to force: if it was not set but idals used
|
|
* ccwchain_calc_length would have returned an error.
|
|
*/
|
|
cp->orb.cmd.c64 = 1;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
/**
|
|
* cp_free() - free resources for channel program.
|
|
* @cp: channel_program on which to perform the operation
|
|
*
|
|
* This unpins the memory pages and frees the memory space occupied by
|
|
* @cp, which must have been returned by a previous call to cp_init().
|
|
* Otherwise, undefined behavior occurs.
|
|
*/
|
|
void cp_free(struct channel_program *cp)
|
|
{
|
|
struct vfio_device *vdev =
|
|
&container_of(cp, struct vfio_ccw_private, cp)->vdev;
|
|
struct ccwchain *chain, *temp;
|
|
int i;
|
|
|
|
if (!cp->initialized)
|
|
return;
|
|
|
|
cp->initialized = false;
|
|
list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) {
|
|
for (i = 0; i < chain->ch_len; i++) {
|
|
page_array_unpin_free(chain->ch_pa + i, vdev);
|
|
ccwchain_cda_free(chain, i);
|
|
}
|
|
ccwchain_free(chain);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cp_prefetch() - translate a guest physical address channel program to
|
|
* a real-device runnable channel program.
|
|
* @cp: channel_program on which to perform the operation
|
|
*
|
|
* This function translates the guest-physical-address channel program
|
|
* and stores the result to ccwchain list. @cp must have been
|
|
* initialized by a previous call with cp_init(). Otherwise, undefined
|
|
* behavior occurs.
|
|
* For each chain composing the channel program:
|
|
* - On entry ch_len holds the count of CCWs to be translated.
|
|
* - On exit ch_len is adjusted to the count of successfully translated CCWs.
|
|
* This allows cp_free to find in ch_len the count of CCWs to free in a chain.
|
|
*
|
|
* The S/390 CCW Translation APIS (prefixed by 'cp_') are introduced
|
|
* as helpers to do ccw chain translation inside the kernel. Basically
|
|
* they accept a channel program issued by a virtual machine, and
|
|
* translate the channel program to a real-device runnable channel
|
|
* program.
|
|
*
|
|
* These APIs will copy the ccws into kernel-space buffers, and update
|
|
* the guest phsical addresses with their corresponding host physical
|
|
* addresses. Then channel I/O device drivers could issue the
|
|
* translated channel program to real devices to perform an I/O
|
|
* operation.
|
|
*
|
|
* These interfaces are designed to support translation only for
|
|
* channel programs, which are generated and formatted by a
|
|
* guest. Thus this will make it possible for things like VFIO to
|
|
* leverage the interfaces to passthrough a channel I/O mediated
|
|
* device in QEMU.
|
|
*
|
|
* We support direct ccw chaining by translating them to idal ccws.
|
|
*
|
|
* Returns:
|
|
* %0 on success and a negative error value on failure.
|
|
*/
|
|
int cp_prefetch(struct channel_program *cp)
|
|
{
|
|
struct ccwchain *chain;
|
|
int len, idx, ret;
|
|
|
|
/* this is an error in the caller */
|
|
if (!cp->initialized)
|
|
return -EINVAL;
|
|
|
|
list_for_each_entry(chain, &cp->ccwchain_list, next) {
|
|
len = chain->ch_len;
|
|
for (idx = 0; idx < len; idx++) {
|
|
ret = ccwchain_fetch_one(chain, idx, cp);
|
|
if (ret)
|
|
goto out_err;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
out_err:
|
|
/* Only cleanup the chain elements that were actually translated. */
|
|
chain->ch_len = idx;
|
|
list_for_each_entry_continue(chain, &cp->ccwchain_list, next) {
|
|
chain->ch_len = 0;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cp_get_orb() - get the orb of the channel program
|
|
* @cp: channel_program on which to perform the operation
|
|
* @intparm: new intparm for the returned orb
|
|
* @lpm: candidate value of the logical-path mask for the returned orb
|
|
*
|
|
* This function returns the address of the updated orb of the channel
|
|
* program. Channel I/O device drivers could use this orb to issue a
|
|
* ssch.
|
|
*/
|
|
union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm)
|
|
{
|
|
union orb *orb;
|
|
struct ccwchain *chain;
|
|
struct ccw1 *cpa;
|
|
|
|
/* this is an error in the caller */
|
|
if (!cp->initialized)
|
|
return NULL;
|
|
|
|
orb = &cp->orb;
|
|
|
|
orb->cmd.intparm = intparm;
|
|
orb->cmd.fmt = 1;
|
|
orb->cmd.key = PAGE_DEFAULT_KEY >> 4;
|
|
|
|
if (orb->cmd.lpm == 0)
|
|
orb->cmd.lpm = lpm;
|
|
|
|
chain = list_first_entry(&cp->ccwchain_list, struct ccwchain, next);
|
|
cpa = chain->ch_ccw;
|
|
orb->cmd.cpa = (__u32) __pa(cpa);
|
|
|
|
return orb;
|
|
}
|
|
|
|
/**
|
|
* cp_update_scsw() - update scsw for a channel program.
|
|
* @cp: channel_program on which to perform the operation
|
|
* @scsw: I/O results of the channel program and also the target to be
|
|
* updated
|
|
*
|
|
* @scsw contains the I/O results of the channel program that pointed
|
|
* to by @cp. However what @scsw->cpa stores is a host physical
|
|
* address, which is meaningless for the guest, which is waiting for
|
|
* the I/O results.
|
|
*
|
|
* This function updates @scsw->cpa to its coressponding guest physical
|
|
* address.
|
|
*/
|
|
void cp_update_scsw(struct channel_program *cp, union scsw *scsw)
|
|
{
|
|
struct ccwchain *chain;
|
|
u32 cpa = scsw->cmd.cpa;
|
|
u32 ccw_head;
|
|
|
|
if (!cp->initialized)
|
|
return;
|
|
|
|
/*
|
|
* LATER:
|
|
* For now, only update the cmd.cpa part. We may need to deal with
|
|
* other portions of the schib as well, even if we don't return them
|
|
* in the ioctl directly. Path status changes etc.
|
|
*/
|
|
list_for_each_entry(chain, &cp->ccwchain_list, next) {
|
|
ccw_head = (u32)(u64)chain->ch_ccw;
|
|
/*
|
|
* On successful execution, cpa points just beyond the end
|
|
* of the chain.
|
|
*/
|
|
if (is_cpa_within_range(cpa, ccw_head, chain->ch_len + 1)) {
|
|
/*
|
|
* (cpa - ccw_head) is the offset value of the host
|
|
* physical ccw to its chain head.
|
|
* Adding this value to the guest physical ccw chain
|
|
* head gets us the guest cpa.
|
|
*/
|
|
cpa = chain->ch_iova + (cpa - ccw_head);
|
|
break;
|
|
}
|
|
}
|
|
|
|
scsw->cmd.cpa = cpa;
|
|
}
|
|
|
|
/**
|
|
* cp_iova_pinned() - check if an iova is pinned for a ccw chain.
|
|
* @cp: channel_program on which to perform the operation
|
|
* @iova: the iova to check
|
|
* @length: the length to check from @iova
|
|
*
|
|
* If the @iova is currently pinned for the ccw chain, return true;
|
|
* else return false.
|
|
*/
|
|
bool cp_iova_pinned(struct channel_program *cp, u64 iova, u64 length)
|
|
{
|
|
struct ccwchain *chain;
|
|
int i;
|
|
|
|
if (!cp->initialized)
|
|
return false;
|
|
|
|
list_for_each_entry(chain, &cp->ccwchain_list, next) {
|
|
for (i = 0; i < chain->ch_len; i++)
|
|
if (page_array_iova_pinned(chain->ch_pa + i, iova, length))
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|