[PATCH v3 4/5] s390/vfio-ap: Add write support to sysfs attr ap_config

Jason J. Herne
2024-03-13T20:58:17Z

Allow writing a complete set of masks to ap_config. Doing so will
cause the vfio-ap driver to replace the vfio-ap mediated device's
matrix masks with the given set of masks. If the given state cannot
be set, then no changes are made to the vfio-ap mediated device.

The format of the data written to ap_config is as follows:
{amask},{dmask},{cmask}\n

\n is a newline character.

amask, dmask, and cmask are masks identifying which adapters, domains,
and control domains should be assigned to the mediated device.

The format of a mask is as follows:
0xNN..NN

Where NN..NN is 64 hexadecimal characters representing a 256-bit value.
The leftmost (highest order) bit represents adapter/domain 0.

For an example set of masks that represent your mdev's current
configuration, simply cat ap_config.

This attribute is intended to be used by an mdevctl callout script
supporting the mdev type vfio_ap-passthrough to atomically update a
vfio-ap mediated device's state.

Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 186 ++++++++++++++++++++++++--
drivers/s390/crypto/vfio_ap_private.h | 6 +-
2 files changed, 176 insertions(+), 16 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 1499c2181122..05b1d311b31f 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1119,20 +1119,29 @@ static void vfio_ap_mdev_unlink_adapter(struct ap_matrix_mdev *matrix_mdev,
}
}

-static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
- unsigned long apid)
+static void vfio_ap_mdev_hot_unplug_adapters(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long *apids)
{
struct vfio_ap_queue *q, *tmpq;
struct list_head qlist;
+ unsigned long apid;
+ bool apcb_update = false;

INIT_LIST_HEAD(&qlist);
- vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, &qlist);

- if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm)) {
- clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
- vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+ for_each_set_bit_inv(apid, apids, AP_DEVICES) {
+ vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, &qlist);
+
+ if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm)) {
+ clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
+ apcb_update = true;
+ }
}

+ /* Only update apcb if needed to avoid impacting guest */
+ if (apcb_update)
+ vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+
vfio_ap_mdev_reset_qlist(&qlist);

list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode) {
@@ -1141,6 +1150,16 @@ static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
}
}

+static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long apid)
+{
+ DECLARE_BITMAP(apids, AP_DEVICES);
+
+ bitmap_zero(apids, AP_DEVICES);
+ set_bit_inv(apid, apids);
+ vfio_ap_mdev_hot_unplug_adapters(matrix_mdev, apids);
+}
+
/**
* unassign_adapter_store - parses the APID from @buf and clears the
* corresponding bit in the mediated matrix device's APM
@@ -1301,20 +1320,29 @@ static void vfio_ap_mdev_unlink_domain(struct ap_matrix_mdev *matrix_mdev,
}
}

-static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
- unsigned long apqi)
+static void vfio_ap_mdev_hot_unplug_domains(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long *apqis)
{
struct vfio_ap_queue *q, *tmpq;
struct list_head qlist;
+ unsigned long apqi;
+ bool apcb_update = false;

INIT_LIST_HEAD(&qlist);
- vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, &qlist);

- if (test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm)) {
- clear_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm);
- vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+ for_each_set_bit_inv(apqi, apqis, AP_DOMAINS) {
+ vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, &qlist);
+
+ if (test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm)) {
+ clear_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm);
+ apcb_update = true;
+ }
}

+ /* Only update apcb if needed to avoid impacting guest */
+ if (apcb_update)
+ vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+
vfio_ap_mdev_reset_qlist(&qlist);

list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode) {
@@ -1323,6 +1351,16 @@ static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
}
}

+static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
+ unsigned long apqi)
+{
+ DECLARE_BITMAP(apqis, AP_DOMAINS);
+
+ bitmap_zero(apqis, AP_DEVICES);
+ set_bit_inv(apqi, apqis);
+ vfio_ap_mdev_hot_unplug_domains(matrix_mdev, apqis);
+}
+
/**
* unassign_domain_store - parses the APQI from @buf and clears the
* corresponding bit in the mediated matrix device's AQM
@@ -1590,10 +1628,132 @@ static ssize_t ap_config_show(struct device *dev, struct device_attribute *attr,
return idx;
}

+/* Number of characters needed for a complete hex mask representing the bits in .. */
+#define AP_DEVICES_STRLEN (AP_DEVICES/4 + 3)
+#define AP_DOMAINS_STRLEN (AP_DOMAINS/4 + 3)
+#define AP_CONFIG_STRLEN (AP_DEVICES_STRLEN + 2 * AP_DOMAINS_STRLEN)
+
+static int parse_bitmap(char **strbufptr, unsigned long *bitmap, int nbits)
+{
+ char *curmask;
+
+ curmask = strsep(strbufptr, ",\n");
+ if (!curmask)
+ return -EINVAL;
+
+ bitmap_clear(bitmap, 0, nbits);
+ return ap_hex2bitmap(curmask, bitmap, nbits);
+}
+
+static int ap_matrix_overflow_check(struct ap_matrix_mdev *matrix_mdev)
+{
+ unsigned long bit;
+
+ for_each_set_bit_inv(bit, matrix_mdev->matrix.apm, AP_DEVICES) {
+ if (bit > matrix_mdev->matrix.apm_max)
+ return -ENODEV;
+ }
+
+ for_each_set_bit_inv(bit, matrix_mdev->matrix.aqm, AP_DOMAINS) {
+ if (bit > matrix_mdev->matrix.aqm_max)
+ return -ENODEV;
+ }
+
+ for_each_set_bit_inv(bit, matrix_mdev->matrix.adm, AP_DOMAINS) {
+ if (bit > matrix_mdev->matrix.adm_max)
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void ap_matrix_copy(struct ap_matrix *dst, struct ap_matrix *src)
+{
+ bitmap_copy(dst->apm, src->apm, AP_DEVICES);
+ bitmap_copy(dst->aqm, src->aqm, AP_DOMAINS);
+ bitmap_copy(dst->adm, src->adm, AP_DOMAINS);
+}
+
static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
- return count;
+ struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
+ struct ap_matrix m_new, m_old, m_added, m_removed;
+ DECLARE_BITMAP(apm_filtered, AP_DEVICES);
+ unsigned long newbit;
+ char *newbuf, *rest;
+ int rc = count;
+ bool do_update;
+
+ newbuf = rest = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
+ if (!newbuf)
+ return -ENOMEM;
+
+ mutex_lock(&ap_perms_mutex);
+ get_update_locks_for_mdev(matrix_mdev);
+
+ /* Save old state */
+ ap_matrix_copy(&m_old, &matrix_mdev->matrix);
+
+ if (parse_bitmap(&rest, m_new.apm, AP_DEVICES) ||
+ parse_bitmap(&rest, m_new.aqm, AP_DOMAINS) ||
+ parse_bitmap(&rest, m_new.adm, AP_DOMAINS)) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ bitmap_andnot(m_removed.apm, m_old.apm, m_new.apm, AP_DEVICES);
+ bitmap_andnot(m_removed.aqm, m_old.aqm, m_new.aqm, AP_DOMAINS);
+ bitmap_andnot(m_added.apm, m_new.apm, m_old.apm, AP_DEVICES);
+ bitmap_andnot(m_added.aqm, m_new.aqm, m_old.aqm, AP_DOMAINS);
+
+ /* Need new bitmaps in matrix_mdev for validation */
+ ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+
+ /* Ensure new state is valid, else undo new state */
+ rc = vfio_ap_mdev_validate_masks(matrix_mdev);
+ if (rc) {
+ ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+ goto out;
+ }
+ rc = ap_matrix_overflow_check(matrix_mdev);
+ if (rc) {
+ ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+ goto out;
+ }
+ rc = count;
+
+ /* Need old bitmaps in matrix_mdev for unplug/unlink */
+ ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+
+ /* Unlink removed adapters/domains */
+ vfio_ap_mdev_hot_unplug_adapters(matrix_mdev, m_removed.apm);
+ vfio_ap_mdev_hot_unplug_domains(matrix_mdev, m_removed.aqm);
+
+ /* Need new bitmaps in matrix_mdev for linking new adapters/domains */
+ ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+
+ /* Link newly added adapters */
+ for_each_set_bit_inv(newbit, m_added.apm, AP_DEVICES)
+ vfio_ap_mdev_link_adapter(matrix_mdev, newbit);
+
+ for_each_set_bit_inv(newbit, m_added.aqm, AP_DOMAINS)
+ vfio_ap_mdev_link_domain(matrix_mdev, newbit);
+
+ /* filter resources not bound to vfio-ap */
+ do_update = vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered);
+ do_update |= vfio_ap_mdev_filter_cdoms(matrix_mdev);
+
+ /* Apply changes to shadow apbc if things changed */
+ if (do_update) {
+ vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+ reset_queues_for_apids(matrix_mdev, apm_filtered);
+ }
+out:
+ release_update_locks_for_mdev(matrix_mdev);
+ mutex_unlock(&ap_perms_mutex);
+ kfree(newbuf);
+ return rc;
}
static DEVICE_ATTR_RW(ap_config);

diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 98d37aa27044..437a161c8659 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -75,11 +75,11 @@ extern struct ap_matrix_dev *matrix_dev;
*/
struct ap_matrix {
unsigned long apm_max;
- DECLARE_BITMAP(apm, 256);
+ DECLARE_BITMAP(apm, AP_DEVICES);
unsigned long aqm_max;
- DECLARE_BITMAP(aqm, 256);
+ DECLARE_BITMAP(aqm, AP_DOMAINS);
unsigned long adm_max;
- DECLARE_BITMAP(adm, 256);
+ DECLARE_BITMAP(adm, AP_DOMAINS);
};

/**
--
2.41.0