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Refactoring of the vfio-ccw cp handling, simplifying the

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code and avoiding unneeded allocating/copying.
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Merge tag 'vfio-ccw-20190621' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw into features

Refactoring of the vfio-ccw cp handling, simplifying the
code and avoiding unneeded allocating/copying.

* tag 'vfio-ccw-20190621' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw:
  vfio-ccw: Remove copy_ccw_from_iova()
  vfio-ccw: Factor out the ccw0-to-ccw1 transition
  vfio-ccw: Copy CCW data outside length calculation
  vfio-ccw: Skip second copy of guest cp to host
  vfio-ccw: Move guest_cp storage into common struct
  s390/cio: Combine direct and indirect CCW paths
  vfio-ccw: Rearrange IDAL allocation in direct CCW
  vfio-ccw: Remove pfn_array_table
  vfio-ccw: Adjust the first IDAW outside of the nested loops
  vfio-ccw: Rearrange pfn_array and pfn_array_table arrays
  s390/cio: Use generalized CCW handler in cp_init()
  s390/cio: Generalize the TIC handler
  s390/cio: Refactor the routine that handles TIC CCWs
  s390/cio: Squash cp_free() and cp_unpin_free()

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Vasily Gorbik 2019-06-24 17:02:28 +02:00
commit 9de3191249
3 changed files with 158 additions and 285 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

429
drivers/s390/cio/vfio_ccw_cp.c
View file

@ -16,12 +16,6 @@
#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;
@ -33,11 +27,6 @@ struct pfn_array {
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;
@ -46,7 +35,7 @@ struct ccwchain {
/* Count of the valid ccws in chain. */
int ch_len;
/* Pinned PAGEs for the original data. */
struct pfn_array_table *ch_pat;
struct pfn_array *ch_pa;
};
/*
@ -139,55 +128,23 @@ static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev)
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)
static bool pfn_array_iova_pinned(struct pfn_array *pa, unsigned long iova)
{
unsigned long iova_pfn = iova >> PAGE_SHIFT;
int i;
for (i = 0; i < pat->pat_nr; i++)
pfn_array_unpin_free(pat->pat_pa + i, mdev);
if (pat->pat_nr) {
kfree(pat->pat_pa);
pat->pat_pa = NULL;
pat->pat_nr = 0;
}
}
static bool pfn_array_table_iova_pinned(struct pfn_array_table *pat,
unsigned long iova)
{
struct pfn_array *pa = pat->pat_pa;
unsigned long iova_pfn = iova >> PAGE_SHIFT;
int i, j;
for (i = 0; i < pat->pat_nr; i++, pa++)
for (j = 0; j < pa->pa_nr; j++)
if (pa->pa_iova_pfn[j] == iova_pfn)
return true;
for (i = 0; i < pa->pa_nr; i++)
if (pa->pa_iova_pfn[i] == iova_pfn)
return true;
return false;
}
/* Create the list idal words for a pfn_array_table. */
static inline void pfn_array_table_idal_create_words(
struct pfn_array_table *pat,
/* Create the list of IDAL words for a pfn_array. */
static inline void pfn_array_idal_create_words(
struct pfn_array *pa,
unsigned long *idaws)
{
struct pfn_array *pa;
int i, j, k;
int i;
/*
* Idal words (execept the first one) rely on the memory being 4k
@ -196,18 +153,35 @@ static inline void pfn_array_table_idal_create_words(
* there will be no problem here to simply use the phys to create an
* idaw.
*/
k = 0;
for (i = 0; i < pat->pat_nr; i++) {
pa = pat->pat_pa + i;
for (j = 0; j < pa->pa_nr; j++) {
idaws[k] = pa->pa_pfn[j] << PAGE_SHIFT;
if (k == 0)
idaws[k] += pa->pa_iova & (PAGE_SIZE - 1);
k++;
}
}
for (i = 0; i < pa->pa_nr; i++)
idaws[i] = pa->pa_pfn[i] << PAGE_SHIFT;
/* Adjust the first IDAW, since it may not start on a page boundary */
idaws[0] += pa->pa_iova & (PAGE_SIZE - 1);
}
void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
{
struct ccw0 ccw0;
struct ccw1 *pccw1 = source;
int i;
for (i = 0; i < len; i++) {
ccw0 = *(struct ccw0 *)pccw1;
if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
pccw1->cmd_code = CCW_CMD_TIC;
pccw1->flags = 0;
pccw1->count = 0;
} else {
pccw1->cmd_code = ccw0.cmd_code;
pccw1->flags = ccw0.flags;
pccw1->count = ccw0.count;
}
pccw1->cda = ccw0.cda;
pccw1++;
}
}
/*
* Within the domain (@mdev), copy @n bytes from a guest physical
@ -254,40 +228,6 @@ static long copy_from_iova(struct device *mdev,
return l;
}
static long copy_ccw_from_iova(struct channel_program *cp,
struct ccw1 *to, u64 iova,
unsigned long len)
{
struct ccw0 ccw0;
struct ccw1 *pccw1;
int ret;
int i;
ret = copy_from_iova(cp->mdev, to, iova, len * sizeof(struct ccw1));
if (ret)
return ret;
if (!cp->orb.cmd.fmt) {
pccw1 = to;
for (i = 0; i < len; i++) {
ccw0 = *(struct ccw0 *)pccw1;
if ((pccw1->cmd_code & 0x0f) == CCW_CMD_TIC) {
pccw1->cmd_code = CCW_CMD_TIC;
pccw1->flags = 0;
pccw1->count = 0;
} else {
pccw1->cmd_code = ccw0.cmd_code;
pccw1->flags = ccw0.flags;
pccw1->count = ccw0.count;
}
pccw1->cda = ccw0.cda;
pccw1++;
}
}
return ret;
}
/*
* Helpers to operate ccwchain.
*/
@ -377,7 +317,7 @@ static struct ccwchain *ccwchain_alloc(struct channel_program *cp, int len)
/* Make ccw address aligned to 8. */
size = ((sizeof(*chain) + 7L) & -8L) +
sizeof(*chain->ch_ccw) * len +
sizeof(*chain->ch_pat) * len;
sizeof(*chain->ch_pa) * len;
chain = kzalloc(size, GFP_DMA | GFP_KERNEL);
if (!chain)
return NULL;
@ -386,7 +326,7 @@ static struct ccwchain *ccwchain_alloc(struct channel_program *cp, int len)
chain->ch_ccw = (struct ccw1 *)data;
data = (u8 *)(chain->ch_ccw) + sizeof(*chain->ch_ccw) * len;
chain->ch_pat = (struct pfn_array_table *)data;
chain->ch_pa = (struct pfn_array *)data;
chain->ch_len = len;
@ -412,23 +352,6 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
kfree((void *)(u64)ccw->cda);
}
/* Unpin the pages then free the memory resources. */
static void cp_unpin_free(struct channel_program *cp)
{
struct ccwchain *chain, *temp;
int i;
cp->initialized = false;
list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) {
for (i = 0; i < chain->ch_len; i++) {
pfn_array_table_unpin_free(chain->ch_pat + i,
cp->mdev);
ccwchain_cda_free(chain, i);
}
ccwchain_free(chain);
}
}
/**
* ccwchain_calc_length - calculate the length of the ccw chain.
* @iova: guest physical address of the target ccw chain
@ -444,25 +367,9 @@ static void cp_unpin_free(struct channel_program *cp)
*/
static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
{
struct ccw1 *ccw, *p;
int cnt;
struct ccw1 *ccw = cp->guest_cp;
int cnt = 0;
/*
* Copy current chain from guest to host kernel.
* Currently the chain length is limited to CCWCHAIN_LEN_MAX (256).
* So copying 2K is enough (safe).
*/
p = ccw = kcalloc(CCWCHAIN_LEN_MAX, sizeof(*ccw), GFP_KERNEL);
if (!ccw)
return -ENOMEM;
cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX);
if (cnt) {
kfree(ccw);
return cnt;
}
cnt = 0;
do {
cnt++;
@ -471,10 +378,8 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
* orb specified one of the unsupported formats, we defer
* checking for IDAWs in unsupported formats to here.
*/
if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw)) {
kfree(p);
if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw))
return -EOPNOTSUPP;
}
/*
* We want to keep counting if the current CCW has the
@ -493,7 +398,6 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
if (cnt == CCWCHAIN_LEN_MAX + 1)
cnt = -EINVAL;
kfree(p);
return cnt;
}
@ -514,17 +418,23 @@ static int tic_target_chain_exists(struct ccw1 *tic, struct channel_program *cp)
static int ccwchain_loop_tic(struct ccwchain *chain,
struct channel_program *cp);
static int ccwchain_handle_tic(struct ccw1 *tic, struct channel_program *cp)
static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
{
struct ccwchain *chain;
int len, ret;
int len;
/* May transfer to an existing chain. */
if (tic_target_chain_exists(tic, cp))
return 0;
/* Copy 2K (the most we support today) of possible CCWs */
len = copy_from_iova(cp->mdev, cp->guest_cp, cda,
CCWCHAIN_LEN_MAX * sizeof(struct ccw1));
if (len)
return len;
/* Get chain length. */
len = ccwchain_calc_length(tic->cda, cp);
/* Convert any Format-0 CCWs to Format-1 */
if (!cp->orb.cmd.fmt)
convert_ccw0_to_ccw1(cp->guest_cp, len);
/* Count the CCWs in the current chain */
len = ccwchain_calc_length(cda, cp);
if (len < 0)
return len;
@ -532,14 +442,10 @@ static int ccwchain_handle_tic(struct ccw1 *tic, struct channel_program *cp)
chain = ccwchain_alloc(cp, len);
if (!chain)
return -ENOMEM;
chain->ch_iova = tic->cda;
chain->ch_iova = cda;
/* Copy the new chain from user. */
ret = copy_ccw_from_iova(cp, chain->ch_ccw, tic->cda, len);
if (ret) {
ccwchain_free(chain);
return ret;
}
/* Copy the actual CCWs into the new chain */
memcpy(chain->ch_ccw, cp->guest_cp, len * sizeof(struct ccw1));
/* Loop for tics on this new chain. */
return ccwchain_loop_tic(chain, cp);
@ -557,7 +463,12 @@ static int ccwchain_loop_tic(struct ccwchain *chain, struct channel_program *cp)
if (!ccw_is_tic(tic))
continue;
ret = ccwchain_handle_tic(tic, cp);
/* 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;
}
@ -590,131 +501,90 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
struct channel_program *cp)
{
struct ccw1 *ccw;
struct pfn_array_table *pat;
struct pfn_array *pa;
u64 iova;
unsigned long *idaws;
int ret;
int bytes = 1;
int idaw_nr = 1;
ccw = chain->ch_ccw + idx;
if (ccw->count) {
bytes = ccw->count;
idaw_nr = idal_nr_words((void *)(u64)ccw->cda, ccw->count);
}
/*
* Pin data page(s) in memory.
* The number of pages actually is the count of the idaws which will be
* needed when translating a direct ccw to a idal ccw.
*/
pat = chain->ch_pat + idx;
ret = pfn_array_table_init(pat, 1);
if (ret)
goto out_init;
ret = pfn_array_alloc(pat->pat_pa, ccw->cda, bytes);
if (ret < 0)
goto out_unpin;
if (ccw_does_data_transfer(ccw)) {
ret = pfn_array_pin(pat->pat_pa, cp->mdev);
if (ret < 0)
goto out_unpin;
} else {
pat->pat_pa->pa_nr = 0;
}
/* Translate this direct ccw to a idal ccw. */
idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
if (!idaws) {
ret = -ENOMEM;
goto out_unpin;
}
ccw->cda = (__u32) virt_to_phys(idaws);
ccw->flags |= CCW_FLAG_IDA;
pfn_array_table_idal_create_words(pat, idaws);
return 0;
out_unpin:
pfn_array_table_unpin_free(pat, cp->mdev);
out_init:
ccw->cda = 0;
return ret;
}
static int ccwchain_fetch_idal(struct ccwchain *chain,
int idx,
struct channel_program *cp)
{
struct ccw1 *ccw;
struct pfn_array_table *pat;
struct pfn_array *pa;
unsigned long *idaws;
u64 idaw_iova;
unsigned int idaw_nr, idaw_len;
int i, 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 idaws. */
ret = copy_from_iova(cp->mdev, &idaw_iova, ccw->cda, sizeof(idaw_iova));
if (ret)
return ret;
idaw_nr = idal_nr_words((void *)(idaw_iova), bytes);
idaw_len = idaw_nr * sizeof(*idaws);
/* 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(cp->mdev, &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);
/* Pin data page(s) in memory. */
pat = chain->ch_pat + idx;
ret = pfn_array_table_init(pat, idaw_nr);
if (ret)
goto out_init;
/* Translate idal ccw to use new allocated idaws. */
idaws = kzalloc(idaw_len, GFP_DMA | GFP_KERNEL);
/* Allocate an IDAL from host storage */
idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
if (!idaws) {
ret = -ENOMEM;
goto out_unpin;
goto out_init;
}
ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idaw_len);
if (ret)
/*
* Allocate an array of pfn's for 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 = pfn_array_alloc(pa, iova, bytes);
if (ret < 0)
goto out_free_idaws;
ccw->cda = virt_to_phys(idaws);
if (ccw_is_idal(ccw)) {
/* Copy guest IDAL into host IDAL */
ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idal_len);
if (ret)
goto out_unpin;
for (i = 0; i < idaw_nr; i++) {
idaw_iova = *(idaws + i);
pa = pat->pat_pa + i;
ret = pfn_array_alloc(pa, idaw_iova, 1);
if (ret < 0)
goto out_free_idaws;
if (!ccw_does_data_transfer(ccw)) {
pa->pa_nr = 0;
continue;
}
ret = pfn_array_pin(pa, cp->mdev);
if (ret < 0)
goto out_free_idaws;
/*
* Copy guest IDAWs into pfn_array, in case the memory they
* occupy is not contiguous.
*/
for (i = 0; i < idaw_nr; i++)
pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT;
} else {
/*
* No action is required here; the iova addresses in pfn_array
* were initialized sequentially in pfn_array_alloc() beginning
* with the contents of ccw->cda.
*/
}
pfn_array_table_idal_create_words(pat, idaws);
if (ccw_does_data_transfer(ccw)) {
ret = pfn_array_pin(pa, cp->mdev);
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 pfn */
pfn_array_idal_create_words(pa, idaws);
return 0;
out_unpin:
pfn_array_unpin_free(pa, cp->mdev);
out_free_idaws:
kfree(idaws);
out_unpin:
pfn_array_table_unpin_free(pat, cp->mdev);
out_init:
ccw->cda = 0;
return ret;
@ -735,9 +605,6 @@ static int ccwchain_fetch_one(struct ccwchain *chain,
if (ccw_is_tic(ccw))
return ccwchain_fetch_tic(chain, idx, cp);
if (ccw_is_idal(ccw))
return ccwchain_fetch_idal(chain, idx, cp);
return ccwchain_fetch_direct(chain, idx, cp);
}
@ -760,9 +627,7 @@ static int ccwchain_fetch_one(struct ccwchain *chain,
*/
int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
{
u64 iova = orb->cmd.cpa;
struct ccwchain *chain;
int len, ret;
int ret;
/*
* XXX:
@ -775,28 +640,11 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
memcpy(&cp->orb, orb, sizeof(*orb));
cp->mdev = mdev;
/* Get chain length. */
len = ccwchain_calc_length(iova, cp);
if (len < 0)
return len;
/* Alloc mem for the head chain. */
chain = ccwchain_alloc(cp, len);
if (!chain)
return -ENOMEM;
chain->ch_iova = iova;
/* Copy the head chain from guest. */
ret = copy_ccw_from_iova(cp, chain->ch_ccw, iova, len);
if (ret) {
ccwchain_free(chain);
return ret;
}
/* Now loop for its TICs. */
ret = ccwchain_loop_tic(chain, cp);
/* Build a ccwchain for the first CCW segment */
ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
if (ret)
cp_unpin_free(cp);
cp_free(cp);
/* It is safe to force: if not set but idals used
* ccwchain_calc_length returns an error.
*/
@ -819,8 +667,20 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
*/
void cp_free(struct channel_program *cp)
{
if (cp->initialized)
cp_unpin_free(cp);
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++) {
pfn_array_unpin_free(chain->ch_pa + i, cp->mdev);
ccwchain_cda_free(chain, i);
}
ccwchain_free(chain);
}
}
/**
@ -992,8 +852,7 @@ bool cp_iova_pinned(struct channel_program *cp, u64 iova)
list_for_each_entry(chain, &cp->ccwchain_list, next) {
for (i = 0; i < chain->ch_len; i++)
if (pfn_array_table_iova_pinned(chain->ch_pat + i,
iova))
if (pfn_array_iova_pinned(chain->ch_pa + i, iova))
return true;
}

7
drivers/s390/cio/vfio_ccw_cp.h
View file

@ -16,6 +16,12 @@
#include "orb.h"
/*
* Max length for ccw chain.
* XXX: Limit to 256, need to check more?
*/
#define CCWCHAIN_LEN_MAX 256
/**
* struct channel_program - manage information for channel program
* @ccwchain_list: list head of ccwchains
@ -32,6 +38,7 @@ struct channel_program {
union orb orb;
struct device *mdev;
bool initialized;
struct ccw1 *guest_cp;
};
extern int cp_init(struct channel_program *cp, struct device *mdev,

7
drivers/s390/cio/vfio_ccw_drv.c
View file

@ -129,6 +129,11 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
if (!private)
return -ENOMEM;
private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),
GFP_KERNEL);
if (!private->cp.guest_cp)
goto out_free;
private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
GFP_KERNEL | GFP_DMA);
if (!private->io_region)
@ -169,6 +174,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
if (private->io_region)
kmem_cache_free(vfio_ccw_io_region, private->io_region);
kfree(private->cp.guest_cp);
kfree(private);
return ret;
}
@ -185,6 +191,7 @@ static int vfio_ccw_sch_remove(struct subchannel *sch)
kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
kmem_cache_free(vfio_ccw_io_region, private->io_region);
kfree(private->cp.guest_cp);
kfree(private);
return 0;