// SPDX-License-Identifier: GPL-2.0
/*
* channel program interfaces
*
* Copyright IBM Corp. 2017
*
* Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
* Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
*/
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/iommu.h>
#include <linux/vfio.h>
#include <asm/idals.h>
#include "vfio_ccw_cp.h"
/*
* Max length for ccw chain.
* XXX: Limit to 256, need to check more?
*/
#define CCWCHAIN_LEN_MAX 256
struct pfn_array {
/* Starting guest physical I/O address. */
unsigned long pa_iova;
/* Array that stores PFNs of the pages need to pin. */
unsigned long *pa_iova_pfn;
/* Array that receives PFNs of the pages pinned. */
unsigned long *pa_pfn;
/* Number of pages pinned from @pa_iova. */
int pa_nr;
};
struct pfn_array_table {
struct pfn_array *pat_pa;
int pat_nr;
};
struct ccwchain {
struct list_head next;
struct ccw1 *ch_ccw;
/* Guest physical address of the current chain. */
u64 ch_iova;
/* Count of the valid ccws in chain. */
int ch_len;
/* Pinned PAGEs for the original data. */
struct pfn_array_table *ch_pat;
};
/*
* pfn_array_alloc() - alloc memory for PFNs
* @pa: pfn_array on which to perform the operation
* @iova: target guest physical address
* @len: number of bytes that should be pinned from @iova
*
* Attempt to allocate memory for PFNs.
*
* Usage of pfn_array:
* We expect (pa_nr == 0) and (pa_iova_pfn == NULL), any field in
* this structure will be filled in by this function.
*
* Returns:
* 0 if PFNs are allocated
* -EINVAL if pa->pa_nr is not initially zero, or pa->pa_iova_pfn is not NULL
* -ENOMEM if alloc failed
*/
static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
{
int i;
if (pa->pa_nr || pa->pa_iova_pfn)
return -EINVAL;
pa->pa_iova = iova;
pa->pa_nr = ((iova & ~PAGE_MASK) + len + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
if (!pa->pa_nr)
return -EINVAL;
pa->pa_iova_pfn = kcalloc(pa->pa_nr,
sizeof(*pa->pa_iova_pfn) +
sizeof(*pa->pa_pfn),
GFP_KERNEL);
if (unlikely(!pa->pa_iova_pfn))
return -ENOMEM;
pa->pa_pfn = pa->pa_iova_pfn + pa->pa_nr;
pa->pa_iova_pfn[0] = pa->pa_iova >> PAGE_SHIFT;
pa->pa_pfn[0] = -1ULL;
for (i = 1; i < pa->pa_nr; i++) {
pa->pa_iova_pfn[i] = pa->pa_iova_pfn[i - 1] + 1;
pa->pa_pfn[i] = -1ULL;
}
return 0;
}
/*
* pfn_array_pin() - Pin user pages in memory
* @pa: pfn_array on which to perform the operation
* @mdev: the mediated device to perform pin operations
*
* Returns number of pages pinned upon success.
* If the pin request partially succeeds, or fails completely,
* all pages are left unpinned and a negative error value is returned.
*/
static int pfn_array_pin(struct pfn_array *pa, struct device *mdev)
{
int ret = 0;
ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr,
IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
if (ret < 0) {
goto err_out;
} else if (ret > 0 && ret != pa->pa_nr) {
vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret);
ret = -EINVAL;
goto err_out;
}
return ret;
err_out:
pa->pa_nr = 0;
return ret;
}
/* Unpin the pages before releasing the memory. */
static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev)
{
/* Only unpin if any pages were pinned to begin with */
if (pa->pa_nr)
vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr);
pa->pa_nr = 0;
kfree(pa->pa_iova_pfn);
}
static int pfn_array_table_init(struct pfn_array_table *pat, int nr)
{
pat->pat_pa = kcalloc(nr, sizeof(*pat->pat_pa), GFP_KERNEL);
if (unlikely(ZERO_OR_NULL_PTR(pat->pat_pa))) {
pat->pat_nr = 0;
return -ENOMEM;
}
pat->pat_nr = nr;
return 0;
}
static void pfn_array_table_unpin_free(struct pfn_array_table *pat,
struct device *mdev)
{
int i;
for (i = 0; i < pat->pat_nr; i++)
pfn_array_unpin_free(pat->pat_pa + i,