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virtio, vhost: fixes, tweaks

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virtio balloon page hinting support
 vhost scsi control queue
 
 misc fixes.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio/vhost updates from Michael Tsirkin:
 "Fixes and tweaks:

   - virtio balloon page hinting support

   - vhost scsi control queue

   - misc fixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  MAINTAINERS: remove reference to bogus vsock file
  vhost/scsi: Use common handling code in request queue handler
  vhost/scsi: Extract common handling code from control queue handler
  vhost/scsi: Respond to control queue operations
  vhost/scsi: truncate T10 PI iov_iter to prot_bytes
  virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON
  mm/page_poison: expose page_poisoning_enabled to kernel modules
  virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
  kvm_config: add CONFIG_VIRTIO_MENU
This commit is contained in:
Linus Torvalds 2018-11-01 14:42:49 -07:00
commit b5b1de3537
6 changed files with 688 additions and 134 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
MAINTAINERS
View File

@ -15858,7 +15858,6 @@ F: net/vmw_vsock/virtio_transport_common.c
F: net/vmw_vsock/virtio_transport.c
F: drivers/net/vsockmon.c
F: drivers/vhost/vsock.c
F: drivers/vhost/vsock.h
F: tools/testing/vsock/
VIRTIO CONSOLE DRIVER

426
drivers/vhost/scsi.c
View File

@ -203,6 +203,19 @@ struct vhost_scsi {
int vs_events_nr; /* num of pending events, protected by vq->mutex */
};
/*
* Context for processing request and control queue operations.
*/
struct vhost_scsi_ctx {
int head;
unsigned int out, in;
size_t req_size, rsp_size;
size_t out_size, in_size;
u8 *target, *lunp;
void *req;
struct iov_iter out_iter;
};
static struct workqueue_struct *vhost_scsi_workqueue;
/* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */
@ -800,24 +813,120 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs,
pr_err("Faulted on virtio_scsi_cmd_resp\n");
}
static int
vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
struct vhost_scsi_ctx *vc)
{
int ret = -ENXIO;
vc->head = vhost_get_vq_desc(vq, vq->iov,
ARRAY_SIZE(vq->iov), &vc->out, &vc->in,
NULL, NULL);
pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
vc->head, vc->out, vc->in);
/* On error, stop handling until the next kick. */
if (unlikely(vc->head < 0))
goto done;
/* Nothing new? Wait for eventfd to tell us they refilled. */
if (vc->head == vq->num) {
if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
vhost_disable_notify(&vs->dev, vq);
ret = -EAGAIN;
}
goto done;
}
/*
* Get the size of request and response buffers.
* FIXME: Not correct for BIDI operation
*/
vc->out_size = iov_length(vq->iov, vc->out);
vc->in_size = iov_length(&vq->iov[vc->out], vc->in);
/*
* Copy over the virtio-scsi request header, which for a
* ANY_LAYOUT enabled guest may span multiple iovecs, or a
* single iovec may contain both the header + outgoing
* WRITE payloads.
*
* copy_from_iter() will advance out_iter, so that it will
* point at the start of the outgoing WRITE payload, if
* DMA_TO_DEVICE is set.
*/
iov_iter_init(&vc->out_iter, WRITE, vq->iov, vc->out, vc->out_size);
ret = 0;
done:
return ret;
}
static int
vhost_scsi_chk_size(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc)
{
if (unlikely(vc->in_size < vc->rsp_size)) {
vq_err(vq,
"Response buf too small, need min %zu bytes got %zu",
vc->rsp_size, vc->in_size);
return -EINVAL;
} else if (unlikely(vc->out_size < vc->req_size)) {
vq_err(vq,
"Request buf too small, need min %zu bytes got %zu",
vc->req_size, vc->out_size);
return -EIO;
}
return 0;
}
static int
vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc,
struct vhost_scsi_tpg **tpgp)
{
int ret = -EIO;
if (unlikely(!copy_from_iter_full(vc->req, vc->req_size,
&vc->out_iter))) {
vq_err(vq, "Faulted on copy_from_iter\n");
} else if (unlikely(*vc->lunp != 1)) {
/* virtio-scsi spec requires byte 0 of the lun to be 1 */
vq_err(vq, "Illegal virtio-scsi lun: %u\n", *vc->lunp);
} else {
struct vhost_scsi_tpg **vs_tpg, *tpg;
vs_tpg = vq->private_data; /* validated at handler entry */
tpg = READ_ONCE(vs_tpg[*vc->target]);
if (unlikely(!tpg)) {
vq_err(vq, "Target 0x%x does not exist\n", *vc->target);
} else {
if (tpgp)
*tpgp = tpg;
ret = 0;
}
}
return ret;
}
static void
vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
{
struct vhost_scsi_tpg **vs_tpg, *tpg;
struct virtio_scsi_cmd_req v_req;
struct virtio_scsi_cmd_req_pi v_req_pi;
struct vhost_scsi_ctx vc;
struct vhost_scsi_cmd *cmd;
struct iov_iter out_iter, in_iter, prot_iter, data_iter;
struct iov_iter in_iter, prot_iter, data_iter;
u64 tag;
u32 exp_data_len, data_direction;
unsigned int out = 0, in = 0;
int head, ret, prot_bytes;
size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp);
size_t out_size, in_size;
int ret, prot_bytes;
u16 lun;
u8 *target, *lunp, task_attr;
u8 task_attr;
bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
void *req, *cdb;
void *cdb;
mutex_lock(&vq->mutex);
/*
@ -828,85 +937,47 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (!vs_tpg)
goto out;
memset(&vc, 0, sizeof(vc));
vc.rsp_size = sizeof(struct virtio_scsi_cmd_resp);
vhost_disable_notify(&vs->dev, vq);
for (;;) {
head = vhost_get_vq_desc(vq, vq->iov,
ARRAY_SIZE(vq->iov), &out, &in,
NULL, NULL);
pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
head, out, in);
/* On error, stop handling until the next kick. */
if (unlikely(head < 0))
break;
/* Nothing new? Wait for eventfd to tell us they refilled. */
if (head == vq->num) {
if (unlikely(vhost_enable_notify(&vs->dev, vq))) {
vhost_disable_notify(&vs->dev, vq);
continue;
}
break;
}
/*
* Check for a sane response buffer so we can report early
* errors back to the guest.
*/
if (unlikely(vq->iov[out].iov_len < rsp_size)) {
vq_err(vq, "Expecting at least virtio_scsi_cmd_resp"
" size, got %zu bytes\n", vq->iov[out].iov_len);
break;
}
ret = vhost_scsi_get_desc(vs, vq, &vc);
if (ret)
goto err;
/*
* Setup pointers and values based upon different virtio-scsi
* request header if T10_PI is enabled in KVM guest.
*/
if (t10_pi) {
req = &v_req_pi;
req_size = sizeof(v_req_pi);
lunp = &v_req_pi.lun[0];
target = &v_req_pi.lun[1];
vc.req = &v_req_pi;
vc.req_size = sizeof(v_req_pi);
vc.lunp = &v_req_pi.lun[0];
vc.target = &v_req_pi.lun[1];
} else {
req = &v_req;
req_size = sizeof(v_req);
lunp = &v_req.lun[0];
target = &v_req.lun[1];
vc.req = &v_req;
vc.req_size = sizeof(v_req);
vc.lunp = &v_req.lun[0];
vc.target = &v_req.lun[1];
}
/*
* FIXME: Not correct for BIDI operation
*/
out_size = iov_length(vq->iov, out);
in_size = iov_length(&vq->iov[out], in);
/*
* Copy over the virtio-scsi request header, which for a
* ANY_LAYOUT enabled guest may span multiple iovecs, or a
* single iovec may contain both the header + outgoing
* WRITE payloads.
*
* copy_from_iter() will advance out_iter, so that it will
* point at the start of the outgoing WRITE payload, if
* DMA_TO_DEVICE is set.
* Validate the size of request and response buffers.
* Check for a sane response buffer so we can report
* early errors back to the guest.
*/
iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size);
ret = vhost_scsi_chk_size(vq, &vc);
if (ret)
goto err;
if (unlikely(!copy_from_iter_full(req, req_size, &out_iter))) {
vq_err(vq, "Faulted on copy_from_iter\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
/* virtio-scsi spec requires byte 0 of the lun to be 1 */
if (unlikely(*lunp != 1)) {
vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
ret = vhost_scsi_get_req(vq, &vc, &tpg);
if (ret)
goto err;
ret = -EIO; /* bad target on any error from here on */
tpg = READ_ONCE(vs_tpg[*target]);
if (unlikely(!tpg)) {
/* Target does not exist, fail the request */
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
/*
* Determine data_direction by calculating the total outgoing
* iovec sizes + incoming iovec sizes vs. virtio-scsi request +
@ -924,17 +995,17 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
*/
prot_bytes = 0;
if (out_size > req_size) {
if (vc.out_size > vc.req_size) {
data_direction = DMA_TO_DEVICE;
exp_data_len = out_size - req_size;
data_iter = out_iter;
} else if (in_size > rsp_size) {
exp_data_len = vc.out_size - vc.req_size;
data_iter = vc.out_iter;
} else if (vc.in_size > vc.rsp_size) {
data_direction = DMA_FROM_DEVICE;
exp_data_len = in_size - rsp_size;
exp_data_len = vc.in_size - vc.rsp_size;
iov_iter_init(&in_iter, READ, &vq->iov[out], in,
rsp_size + exp_data_len);
iov_iter_advance(&in_iter, rsp_size);
iov_iter_init(&in_iter, READ, &vq->iov[vc.out], vc.in,
vc.rsp_size + exp_data_len);
iov_iter_advance(&in_iter, vc.rsp_size);
data_iter = in_iter;
} else {
data_direction = DMA_NONE;
@ -950,21 +1021,20 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (data_direction != DMA_TO_DEVICE) {
vq_err(vq, "Received non zero pi_bytesout,"
" but wrong data_direction\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
goto err;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
} else if (v_req_pi.pi_bytesin) {
if (data_direction != DMA_FROM_DEVICE) {
vq_err(vq, "Received non zero pi_bytesin,"
" but wrong data_direction\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
goto err;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
}
/*
* Set prot_iter to data_iter, and advance past any
* Set prot_iter to data_iter and truncate it to
* prot_bytes, and advance data_iter past any
* preceeding prot_bytes that may be present.
*
* Also fix up the exp_data_len to reflect only the
@ -973,6 +1043,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (prot_bytes) {
exp_data_len -= prot_bytes;
prot_iter = data_iter;
iov_iter_truncate(&prot_iter, prot_bytes);
iov_iter_advance(&data_iter, prot_bytes);
}
tag = vhost64_to_cpu(vq, v_req_pi.tag);
@ -996,8 +1067,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
vq_err(vq, "Received SCSI CDB with command_size: %d that"
" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
goto err;
}
cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
exp_data_len + prot_bytes,
@ -1005,13 +1075,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
if (IS_ERR(cmd)) {
vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
PTR_ERR(cmd));
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
goto err;
}
cmd->tvc_vhost = vs;
cmd->tvc_vq = vq;
cmd->tvc_resp_iov = vq->iov[out];
cmd->tvc_in_iovs = in;
cmd->tvc_resp_iov = vq->iov[vc.out];
cmd->tvc_in_iovs = vc.in;
pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n",
cmd->tvc_cdb[0], cmd->tvc_lun);
@ -1019,14 +1088,12 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
" %d\n", cmd, exp_data_len, prot_bytes, data_direction);
if (data_direction != DMA_NONE) {
ret = vhost_scsi_mapal(cmd,
prot_bytes, &prot_iter,
exp_data_len, &data_iter);
if (unlikely(ret)) {
if (unlikely(vhost_scsi_mapal(cmd, prot_bytes,
&prot_iter, exp_data_len,
&data_iter))) {
vq_err(vq, "Failed to map iov to sgl\n");
vhost_scsi_release_cmd(&cmd->tvc_se_cmd);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
goto err;
}
}
/*
@ -1034,7 +1101,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
* complete the virtio-scsi request in TCM callback context via
* vhost_scsi_queue_data_in() and vhost_scsi_queue_status()
*/
cmd->tvc_vq_desc = head;
cmd->tvc_vq_desc = vc.head;
/*
* Dispatch cmd descriptor for cmwq execution in process
* context provided by vhost_scsi_workqueue. This also ensures
@ -1043,6 +1110,166 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
*/
INIT_WORK(&cmd->work, vhost_scsi_submission_work);
queue_work(vhost_scsi_workqueue, &cmd->work);
ret = 0;
err:
/*
* ENXIO: No more requests, or read error, wait for next kick
* EINVAL: Invalid response buffer, drop the request
* EIO: Respond with bad target
* EAGAIN: Pending request
*/
if (ret == -ENXIO)
break;
else if (ret == -EIO)
vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
}
out:
mutex_unlock(&vq->mutex);
}
static void
vhost_scsi_send_tmf_reject(struct vhost_scsi *vs,
struct vhost_virtqueue *vq,
struct vhost_scsi_ctx *vc)
{
struct virtio_scsi_ctrl_tmf_resp __user *resp;
struct virtio_scsi_ctrl_tmf_resp rsp;
int ret;
pr_debug("%s\n", __func__);
memset(&rsp, 0, sizeof(rsp));
rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
resp = vq->iov[vc->out].iov_base;
ret = __copy_to_user(resp, &rsp, sizeof(rsp));
if (!ret)
vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
else
pr_err("Faulted on virtio_scsi_ctrl_tmf_resp\n");
}
static void
vhost_scsi_send_an_resp(struct vhost_scsi *vs,
struct vhost_virtqueue *vq,
struct vhost_scsi_ctx *vc)
{
struct virtio_scsi_ctrl_an_resp __user *resp;
struct virtio_scsi_ctrl_an_resp rsp;
int ret;
pr_debug("%s\n", __func__);
memset(&rsp, 0, sizeof(rsp)); /* event_actual = 0 */
rsp.response = VIRTIO_SCSI_S_OK;
resp = vq->iov[vc->out].iov_base;
ret = __copy_to_user(resp, &rsp, sizeof(rsp));
if (!ret)
vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
else
pr_err("Faulted on virtio_scsi_ctrl_an_resp\n");
}
static void
vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
{
union {
__virtio32 type;
struct virtio_scsi_ctrl_an_req an;
struct virtio_scsi_ctrl_tmf_req tmf;
} v_req;
struct vhost_scsi_ctx vc;
size_t typ_size;
int ret;
mutex_lock(&vq->mutex);
/*
* We can handle the vq only after the endpoint is setup by calling the
* VHOST_SCSI_SET_ENDPOINT ioctl.
*/
if (!vq->private_data)
goto out;
memset(&vc, 0, sizeof(vc));
vhost_disable_notify(&vs->dev, vq);
for (;;) {
ret = vhost_scsi_get_desc(vs, vq, &vc);
if (ret)
goto err;
/*
* Get the request type first in order to setup
* other parameters dependent on the type.
*/
vc.req = &v_req.type;
typ_size = sizeof(v_req.type);
if (unlikely(!copy_from_iter_full(vc.req, typ_size,
&vc.out_iter))) {
vq_err(vq, "Faulted on copy_from_iter tmf type\n");
/*
* The size of the response buffer depends on the
* request type and must be validated against it.
* Since the request type is not known, don't send
* a response.
*/
continue;
}
switch (v_req.type) {
case VIRTIO_SCSI_T_TMF:
vc.req = &v_req.tmf;
vc.req_size = sizeof(struct virtio_scsi_ctrl_tmf_req);
vc.rsp_size = sizeof(struct virtio_scsi_ctrl_tmf_resp);
vc.lunp = &v_req.tmf.lun[0];
vc.target = &v_req.tmf.lun[1];
break;
case VIRTIO_SCSI_T_AN_QUERY:
case VIRTIO_SCSI_T_AN_SUBSCRIBE:
vc.req = &v_req.an;
vc.req_size = sizeof(struct virtio_scsi_ctrl_an_req);
vc.rsp_size = sizeof(struct virtio_scsi_ctrl_an_resp);
vc.lunp = &v_req.an.lun[0];
vc.target = NULL;
break;
default:
vq_err(vq, "Unknown control request %d", v_req.type);
continue;
}
/*
* Validate the size of request and response buffers.
* Check for a sane response buffer so we can report
* early errors back to the guest.
*/
ret = vhost_scsi_chk_size(vq, &vc);
if (ret)
goto err;
/*
* Get the rest of the request now that its size is known.
*/
vc.req += typ_size;
vc.req_size -= typ_size;
ret = vhost_scsi_get_req(vq, &vc, NULL);
if (ret)
goto err;
if (v_req.type == VIRTIO_SCSI_T_TMF)
vhost_scsi_send_tmf_reject(vs, vq, &vc);
else
vhost_scsi_send_an_resp(vs, vq, &vc);
err:
/*
* ENXIO: No more requests, or read error, wait for next kick
* EINVAL: Invalid response buffer, drop the request
* EIO: Respond with bad target
* EAGAIN: Pending request
*/
if (ret == -ENXIO)
break;
else if (ret == -EIO)
vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
}
out:
mutex_unlock(&vq->mutex);
@ -1050,7 +1277,12 @@ out:
static void vhost_scsi_ctl_handle_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
poll.work);
struct vhost_scsi *vs = container_of(vq->dev, struct vhost_scsi, dev);
pr_debug("%s: The handling func for control queue.\n", __func__);
vhost_scsi_ctl_handle_vq(vs, vq);
}
static void

380
drivers/virtio/virtio_balloon.c
View File

@ -41,13 +41,34 @@
#define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256
#define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80
#define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \
__GFP_NOMEMALLOC)
/* The order of free page blocks to report to host */
#define VIRTIO_BALLOON_FREE_PAGE_ORDER (MAX_ORDER - 1)
/* The size of a free page block in bytes */
#define VIRTIO_BALLOON_FREE_PAGE_SIZE \
(1 << (VIRTIO_BALLOON_FREE_PAGE_ORDER + PAGE_SHIFT))
#ifdef CONFIG_BALLOON_COMPACTION
static struct vfsmount *balloon_mnt;
#endif
enum virtio_balloon_vq {
VIRTIO_BALLOON_VQ_INFLATE,
VIRTIO_BALLOON_VQ_DEFLATE,
VIRTIO_BALLOON_VQ_STATS,
VIRTIO_BALLOON_VQ_FREE_PAGE,
VIRTIO_BALLOON_VQ_MAX
};
struct virtio_balloon {
struct virtio_device *vdev;
struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq;
/* Balloon's own wq for cpu-intensive work items */
struct workqueue_struct *balloon_wq;
/* The free page reporting work item submitted to the balloon wq */
struct work_struct report_free_page_work;
/* The balloon servicing is delegated to a freezable workqueue. */
struct work_struct update_balloon_stats_work;
@ -57,6 +78,18 @@ struct virtio_balloon {
spinlock_t stop_update_lock;
bool stop_update;
/* The list of allocated free pages, waiting to be given back to mm */
struct list_head free_page_list;
spinlock_t free_page_list_lock;
/* The number of free page blocks on the above list */
unsigned long num_free_page_blocks;
/* The cmd id received from host */
u32 cmd_id_received;
/* The cmd id that is actively in use */
__virtio32 cmd_id_active;
/* Buffer to store the stop sign */
__virtio32 cmd_id_stop;
/* Waiting for host to ack the pages we released. */
wait_queue_head_t acked;
@ -320,17 +353,6 @@ static void stats_handle_request(struct virtio_balloon *vb)
virtqueue_kick(vq);
}
static void virtballoon_changed(struct virtio_device *vdev)
{
struct virtio_balloon *vb = vdev->priv;
unsigned long flags;
spin_lock_irqsave(&vb->stop_update_lock, flags);
if (!vb->stop_update)
queue_work(system_freezable_wq, &vb->update_balloon_size_work);
spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}
static inline s64 towards_target(struct virtio_balloon *vb)
{
s64 target;
@ -347,6 +369,60 @@ static inline s64 towards_target(struct virtio_balloon *vb)
return target - vb->num_pages;
}
/* Gives back @num_to_return blocks of free pages to mm. */
static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb,
unsigned long num_to_return)
{
struct page *page;
unsigned long num_returned;
spin_lock_irq(&vb->free_page_list_lock);
for (num_returned = 0; num_returned < num_to_return; num_returned++) {
page = balloon_page_pop(&vb->free_page_list);
if (!page)
break;
free_pages((unsigned long)page_address(page),
VIRTIO_BALLOON_FREE_PAGE_ORDER);
}
vb->num_free_page_blocks -= num_returned;
spin_unlock_irq(&vb->free_page_list_lock);
return num_returned;
}
static void virtballoon_changed(struct virtio_device *vdev)
{
struct virtio_balloon *vb = vdev->priv;
unsigned long flags;
s64 diff = towards_target(vb);
if (diff) {
spin_lock_irqsave(&vb->stop_update_lock, flags);
if (!vb->stop_update)
queue_work(system_freezable_wq,
&vb->update_balloon_size_work);
spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
virtio_cread(vdev, struct virtio_balloon_config,
free_page_report_cmd_id, &vb->cmd_id_received);
if (vb->cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) {
/* Pass ULONG_MAX to give back all the free pages */
return_free_pages_to_mm(vb, ULONG_MAX);
} else if (vb->cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP &&
vb->cmd_id_received !=
virtio32_to_cpu(vdev, vb->cmd_id_active)) {
spin_lock_irqsave(&vb->stop_update_lock, flags);
if (!vb->stop_update) {
queue_work(vb->balloon_wq,
&vb->report_free_page_work);
}
spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}
}
}
static void update_balloon_size(struct virtio_balloon *vb)
{
u32 actual = vb->num_pages;
@ -389,26 +465,44 @@ static void update_balloon_size_func(struct work_struct *work)
static int init_vqs(struct virtio_balloon *vb)
{
struct virtqueue *vqs[3];
vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request };
static const char * const names[] = { "inflate", "deflate", "stats" };
int err, nvqs;
struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX];
vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX];
const char *names[VIRTIO_BALLOON_VQ_MAX];
int err;
/*
* We expect two virtqueues: inflate and deflate, and
* optionally stat.
* Inflateq and deflateq are used unconditionally. The names[]
* will be NULL if the related feature is not enabled, which will
* cause no allocation for the corresponding virtqueue in find_vqs.
*/
nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
err = virtio_find_vqs(vb->vdev, nvqs, vqs, callbacks, names, NULL);
callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack;
names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate";
callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack;
names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate";
names[VIRTIO_BALLOON_VQ_STATS] = NULL;
names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
names[VIRTIO_BALLOON_VQ_STATS] = "stats";
callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request;
}
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq";
callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
}
err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
vqs, callbacks, names, NULL, NULL);
if (err)
return err;
vb->inflate_vq = vqs[0];
vb->deflate_vq = vqs[1];
vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE];
vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE];
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
struct scatterlist sg;
unsigned int num_stats;
vb->stats_vq = vqs[2];
vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS];
/*
* Prime this virtqueue with one buffer so the hypervisor can
@ -426,9 +520,145 @@ static int init_vqs(struct virtio_balloon *vb)
}
virtqueue_kick(vb->stats_vq);
}
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE];
return 0;
}
static int send_cmd_id_start(struct virtio_balloon *vb)
{
struct scatterlist sg;
struct virtqueue *vq = vb->free_page_vq;
int err, unused;
/* Detach all the used buffers from the vq */
while (virtqueue_get_buf(vq, &unused))
;
vb->cmd_id_active = cpu_to_virtio32(vb->vdev, vb->cmd_id_received);
sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active));
err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL);
if (!err)
virtqueue_kick(vq);
return err;
}
static int send_cmd_id_stop(struct virtio_balloon *vb)
{
struct scatterlist sg;
struct virtqueue *vq = vb->free_page_vq;
int err, unused;
/* Detach all the used buffers from the vq */
while (virtqueue_get_buf(vq, &unused))
;
sg_init_one(&sg, &vb->cmd_id_stop, sizeof(vb->cmd_id_stop));
err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_stop, GFP_KERNEL);
if (!err)
virtqueue_kick(vq);
return err;
}
static int get_free_page_and_send(struct virtio_balloon *vb)
{
struct virtqueue *vq = vb->free_page_vq;
struct page *page;
struct scatterlist sg;
int err, unused;
void *p;
/* Detach all the used buffers from the vq */
while (virtqueue_get_buf(vq, &unused))
;
page = alloc_pages(VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG,
VIRTIO_BALLOON_FREE_PAGE_ORDER);
/*
* When the allocation returns NULL, it indicates that we have got all
* the possible free pages, so return -EINTR to stop.
*/
if (!page)
return -EINTR;
p = page_address(page);
sg_init_one(&sg, p, VIRTIO_BALLOON_FREE_PAGE_SIZE);
/* There is always 1 entry reserved for the cmd id to use. */
if (vq->num_free > 1) {
err = virtqueue_add_inbuf(vq, &sg, 1, p, GFP_KERNEL);
if (unlikely(err)) {
free_pages((unsigned long)p,
VIRTIO_BALLOON_FREE_PAGE_ORDER);
return err;
}
virtqueue_kick(vq);
spin_lock_irq(&vb->free_page_list_lock);
balloon_page_push(&vb->free_page_list, page);
vb->num_free_page_blocks++;
spin_unlock_irq(&vb->free_page_list_lock);
} else {
/*
* The vq has no available entry to add this page block, so
* just free it.
*/
free_pages((unsigned long)p, VIRTIO_BALLOON_FREE_PAGE_ORDER);
}
return 0;
}
static int send_free_pages(struct virtio_balloon *vb)
{
int err;
u32 cmd_id_active;
while (1) {
/*
* If a stop id or a new cmd id was just received from host,
* stop the reporting.
*/
cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active);
if (cmd_id_active != vb->cmd_id_received)
break;
/*
* The free page blocks are allocated and sent to host one by
* one.
*/
err = get_free_page_and_send(vb);
if (err == -EINTR)
break;
else if (unlikely(err))
return err;
}
return 0;
}
static void report_free_page_func(struct work_struct *work)
{
int err;
struct virtio_balloon *vb = container_of(work, struct virtio_balloon,
report_free_page_work);
struct device *dev = &vb->vdev->dev;
/* Start by sending the received cmd id to host with an outbuf. */
err = send_cmd_id_start(vb);
if (unlikely(err))
dev_err(dev, "Failed to send a start id, err = %d\n", err);
err = send_free_pages(vb);
if (unlikely(err))
dev_err(dev, "Failed to send a free page, err = %d\n", err);
/* End by sending a stop id to host with an outbuf. */
err = send_cmd_id_stop(vb);
if (unlikely(err))
dev_err(dev, "Failed to send a stop id, err = %d\n", err);
}
#ifdef CONFIG_BALLOON_COMPACTION
/*
* virtballoon_migratepage - perform the balloon page migration on behalf of
@ -512,6 +742,39 @@ static struct file_system_type balloon_fs = {
#endif /* CONFIG_BALLOON_COMPACTION */
static unsigned long shrink_free_pages(struct virtio_balloon *vb,
unsigned long pages_to_free)
{
unsigned long blocks_to_free, blocks_freed;
pages_to_free = round_up(pages_to_free,
1 << VIRTIO_BALLOON_FREE_PAGE_ORDER);
blocks_to_free = pages_to_free >> VIRTIO_BALLOON_FREE_PAGE_ORDER;
blocks_freed = return_free_pages_to_mm(vb, blocks_to_free);
return blocks_freed << VIRTIO_BALLOON_FREE_PAGE_ORDER;
}
static unsigned long shrink_balloon_pages(struct virtio_balloon *vb,
unsigned long pages_to_free)
{
unsigned long pages_freed = 0;
/*
* One invocation of leak_balloon can deflate at most
* VIRTIO_BALLOON_ARRAY_PFNS_MAX balloon pages, so we call it
* multiple times to deflate pages till reaching pages_to_free.
*/
while (vb->num_pages && pages_to_free) {
pages_freed += leak_balloon(vb, pages_to_free) /
VIRTIO_BALLOON_PAGES_PER_PAGE;
pages_to_free -= pages_freed;
}
update_balloon_size(vb);
return pages_freed;
}
static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker,
struct shrink_control *sc)
{
@ -521,18 +784,15 @@ static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker,
pages_to_free = sc->nr_to_scan * VIRTIO_BALLOON_PAGES_PER_PAGE;
/*
* One invocation of leak_balloon can deflate at most
* VIRTIO_BALLOON_ARRAY_PFNS_MAX balloon pages, so we call it
* multiple times to deflate pages till reaching pages_to_free.
*/
while (vb->num_pages && pages_to_free) {
pages_to_free -= pages_freed;
pages_freed += leak_balloon(vb, pages_to_free);
}
update_balloon_size(vb);
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
pages_freed = shrink_free_pages(vb, pages_to_free);
return pages_freed / VIRTIO_BALLOON_PAGES_PER_PAGE;
if (pages_freed >= pages_to_free)
return pages_freed;
pages_freed += shrink_balloon_pages(vb, pages_to_free - pages_freed);
return pages_freed;
}
static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker,
@ -540,8 +800,12 @@ static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker,
{
struct virtio_balloon *vb = container_of(shrinker,
struct virtio_balloon, shrinker);
unsigned long count;
return vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
count += vb->num_free_page_blocks >> VIRTIO_BALLOON_FREE_PAGE_ORDER;
return count;
}
static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb)
@ -561,6 +825,7 @@ static int virtio_balloon_register_shrinker(struct virtio_balloon *vb)
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
__u32 poison_val;
int err;
if (!vdev->config->get) {
@ -604,6 +869,36 @@ static int virtballoon_probe(struct virtio_device *vdev)
}
vb->vb_dev_info.inode->i_mapping->a_ops = &balloon_aops;
#endif
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
/*
* There is always one entry reserved for cmd id, so the ring
* size needs to be at least two to report free page hints.
*/
if (virtqueue_get_vring_size(vb->free_page_vq) < 2) {
err = -ENOSPC;
goto out_del_vqs;
}
vb->balloon_wq = alloc_workqueue("balloon-wq",
WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0);
if (!vb->balloon_wq) {
err = -ENOMEM;
goto out_del_vqs;
}
INIT_WORK(&vb->report_free_page_work, report_free_page_func);
vb->cmd_id_received = VIRTIO_BALLOON_CMD_ID_STOP;
vb->cmd_id_active = cpu_to_virtio32(vb->vdev,
VIRTIO_BALLOON_CMD_ID_STOP);
vb->cmd_id_stop = cpu_to_virtio32(vb->vdev,
VIRTIO_BALLOON_CMD_ID_STOP);
vb->num_free_page_blocks = 0;
spin_lock_init(&vb->free_page_list_lock);
INIT_LIST_HEAD(&vb->free_page_list);
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) {
memset(&poison_val, PAGE_POISON, sizeof(poison_val));
virtio_cwrite(vb->vdev, struct virtio_balloon_config,
poison_val, &poison_val);
}
}
/*
* We continue to use VIRTIO_BALLOON_F_DEFLATE_ON_OOM to decide if a
* shrinker needs to be registered to relieve memory pressure.
@ -611,7 +906,7 @@ static int virtballoon_probe(struct virtio_device *vdev)
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) {
err = virtio_balloon_register_shrinker(vb);
if (err)
goto out_del_vqs;
goto out_del_balloon_wq;
}
virtio_device_ready(vdev);
@ -619,6 +914,9 @@ static int virtballoon_probe(struct virtio_device *vdev)
virtballoon_changed(vdev);
return 0;
out_del_balloon_wq:
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
destroy_workqueue(vb->balloon_wq);
out_del_vqs:
vdev->config->del_vqs(vdev);
out_free_vb:
@ -652,6 +950,11 @@ static void virtballoon_remove(struct virtio_device *vdev)
cancel_work_sync(&vb->update_balloon_size_work);
cancel_work_sync(&vb->update_balloon_stats_work);
if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
cancel_work_sync(&vb->report_free_page_work);
destroy_workqueue(vb->balloon_wq);
}
remove_common(vb);
#ifdef CONFIG_BALLOON_COMPACTION
if (vb->vb_dev_info.inode)
@ -695,6 +998,9 @@ static int virtballoon_restore(struct virtio_device *vdev)
static int virtballoon_validate(struct virtio_device *vdev)
{
if (!page_poisoning_enabled())
__virtio_clear_bit(vdev, VIRTIO_BALLOON_F_PAGE_POISON);
__virtio_clear_bit(vdev, VIRTIO_F_IOMMU_PLATFORM);
return 0;
}
@ -703,6 +1009,8 @@ static unsigned int features[] = {
VIRTIO_BALLOON_F_MUST_TELL_HOST,
VIRTIO_BALLOON_F_STATS_VQ,
VIRTIO_BALLOON_F_DEFLATE_ON_OOM,
VIRTIO_BALLOON_F_FREE_PAGE_HINT,
VIRTIO_BALLOON_F_PAGE_POISON,
};
static struct virtio_driver virtio_balloon_driver = {

8
include/uapi/linux/virtio_balloon.h
View File

@ -34,15 +34,23 @@
#define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
#define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
#define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
#define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
#define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
/* Size of a PFN in the balloon interface. */
#define VIRTIO_BALLOON_PFN_SHIFT 12
#define VIRTIO_BALLOON_CMD_ID_STOP 0
#define VIRTIO_BALLOON_CMD_ID_DONE 1
struct virtio_balloon_config {
/* Number of pages host wants Guest to give up. */
__u32 num_pages;
/* Number of pages we've actually got in balloon. */
__u32 actual;
/* Free page report command id, readonly by guest */
__u32 free_page_report_cmd_id;
/* Stores PAGE_POISON if page poisoning is in use */
__u32 poison_val;
};
#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */

1
kernel/configs/kvm_guest.config
View File

@ -20,6 +20,7 @@ CONFIG_PARAVIRT=y
CONFIG_KVM_GUEST=y
CONFIG_S390_GUEST=y
CONFIG_VIRTIO=y
CONFIG_VIRTIO_MENU=y
CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_BLK=y
CONFIG_VIRTIO_CONSOLE=y

6
mm/page_poison.c
View File

@ -17,6 +17,11 @@ static int __init early_page_poison_param(char *buf)
}
early_param("page_poison", early_page_poison_param);
/**
* page_poisoning_enabled - check if page poisoning is enabled
*
* Return true if page poisoning is enabled, or false if not.
*/
bool page_poisoning_enabled(void)
{
/*
@ -29,6 +34,7 @@ bool page_poisoning_enabled(void)
(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
debug_pagealloc_enabled()));
}
EXPORT_SYMBOL_GPL(page_poisoning_enabled);
static void poison_page(struct page *page)
{