if (rc)
goto out_free;
- vas_user_win_add_mm_context(&txwin->vas_win.task_ref);
txwin->win_type = cop_feat_caps->win_type;
mutex_lock(&vas_pseries_mutex);
- list_add(&txwin->win_list, &caps->list);
+ /*
+ * Possible to lose the acquired credit with DLPAR core
+ * removal after the window is opened. So if there are any
+ * closed windows (means with lost credits), do not give new
+ * window to user space. New windows will be opened only
+ * after the existing windows are reopened when credits are
+ * available.
+ */
+ if (!caps->nr_close_wins) {
+ list_add(&txwin->win_list, &caps->list);
+ caps->nr_open_windows++;
+ mutex_unlock(&vas_pseries_mutex);
+ vas_user_win_add_mm_context(&txwin->vas_win.task_ref);
+ return &txwin->vas_win;
+ }
mutex_unlock(&vas_pseries_mutex);
- return &txwin->vas_win;
+ put_vas_user_win_ref(&txwin->vas_win.task_ref);
+ rc = -EBUSY;
+ pr_err("No credit is available to allocate window\n");
out_free:
/*
caps = &vascaps[win->win_type].caps;
mutex_lock(&vas_pseries_mutex);
- rc = deallocate_free_window(win);
- if (rc) {
- mutex_unlock(&vas_pseries_mutex);
- return rc;
- }
+ /*
+ * VAS window is already closed in the hypervisor when
+ * lost the credit. So just remove the entry from
+ * the list, remove task references and free vas_window
+ * struct.
+ */
+ if (win->vas_win.status & VAS_WIN_NO_CRED_CLOSE) {
+ rc = deallocate_free_window(win);
+ if (rc) {
+ mutex_unlock(&vas_pseries_mutex);
+ return rc;
+ }
+ } else
+ vascaps[win->win_type].nr_close_wins--;
list_del(&win->win_list);
atomic_dec(&caps->nr_used_credits);
+ vascaps[win->win_type].nr_open_windows--;
mutex_unlock(&vas_pseries_mutex);
put_vas_user_win_ref(&vwin->task_ref);
memset(vcaps, 0, sizeof(*vcaps));
INIT_LIST_HEAD(&vcaps->list);
+ vcaps->feat = feat;
caps = &vcaps->caps;
rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, feat,
return 0;
}
+/*
+ * The hypervisor reduces the available credits if the LPAR lost core. It
+ * means the excessive windows should not be active and the user space
+ * should not be using these windows to send compression requests to NX.
+ * So the kernel closes the excessive windows and unmap the paste address
+ * such that the user space receives paste instruction failure. Then up to
+ * the user space to fall back to SW compression and manage with the
+ * existing windows.
+ */
+static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds)
+{
+ struct pseries_vas_window *win, *tmp;
+ struct vas_user_win_ref *task_ref;
+ struct vm_area_struct *vma;
+ int rc = 0;
+
+ list_for_each_entry_safe(win, tmp, &vcap->list, win_list) {
+ /*
+ * This window is already closed due to lost credit
+ * before. Go for next window.
+ */
+ if (win->vas_win.status & VAS_WIN_NO_CRED_CLOSE)
+ continue;
+
+ task_ref = &win->vas_win.task_ref;
+ mutex_lock(&task_ref->mmap_mutex);
+ vma = task_ref->vma;
+ /*
+ * Number of available credits are reduced, So select
+ * and close windows.
+ */
+ win->vas_win.status |= VAS_WIN_NO_CRED_CLOSE;
+
+ mmap_write_lock(task_ref->mm);
+ /*
+ * vma is set in the original mapping. But this mapping
+ * is done with mmap() after the window is opened with ioctl.
+ * so we may not see the original mapping if the core remove
+ * is done before the original mmap() and after the ioctl.
+ */
+ if (vma)
+ zap_page_range(vma, vma->vm_start,
+ vma->vm_end - vma->vm_start);
+
+ mmap_write_unlock(task_ref->mm);
+ mutex_unlock(&task_ref->mmap_mutex);
+ /*
+ * Close VAS window in the hypervisor, but do not
+ * free vas_window struct since it may be reused
+ * when the credit is available later (DLPAR with
+ * adding cores). This struct will be used
+ * later when the process issued with close(FD).
+ */
+ rc = deallocate_free_window(win);
+ if (rc)
+ return rc;
+
+ vcap->nr_close_wins++;
+
+ if (!--excess_creds)
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * Get new VAS capabilities when the core add/removal configuration
+ * changes. Reconfig window configurations based on the credits
+ * availability from this new capabilities.
+ */
+static int vas_reconfig_capabilties(u8 type)
+{
+ struct hv_vas_cop_feat_caps *hv_caps;
+ struct vas_cop_feat_caps *caps;
+ int old_nr_creds, new_nr_creds;
+ struct vas_caps *vcaps;
+ int rc = 0, nr_active_wins;
+
+ if (type >= VAS_MAX_FEAT_TYPE) {
+ pr_err("Invalid credit type %d\n", type);
+ return -EINVAL;
+ }
+
+ vcaps = &vascaps[type];
+ caps = &vcaps->caps;
+
+ hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
+ if (!hv_caps)
+ return -ENOMEM;
+
+ mutex_lock(&vas_pseries_mutex);
+ rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, vcaps->feat,
+ (u64)virt_to_phys(hv_caps));
+ if (rc)
+ goto out;
+
+ new_nr_creds = be16_to_cpu(hv_caps->target_lpar_creds);
+
+ old_nr_creds = atomic_read(&caps->nr_total_credits);
+
+ atomic_set(&caps->nr_total_credits, new_nr_creds);
+ /*
+ * The total number of available credits may be decreased or
+ * inceased with DLPAR operation. Means some windows have to be
+ * closed / reopened. Hold the vas_pseries_mutex so that the
+ * the user space can not open new windows.
+ */
+ if (old_nr_creds > new_nr_creds) {
+ /*
+ * # active windows is more than new LPAR available
+ * credits. So close the excessive windows.
+ * On pseries, each window will have 1 credit.
+ */
+ nr_active_wins = vcaps->nr_open_windows - vcaps->nr_close_wins;
+ if (nr_active_wins > new_nr_creds)
+ rc = reconfig_close_windows(vcaps,
+ nr_active_wins - new_nr_creds);
+ }
+
+out:
+ mutex_unlock(&vas_pseries_mutex);
+ kfree(hv_caps);
+ return rc;
+}
+/*
+ * Total number of default credits available (target_credits)
+ * in LPAR depends on number of cores configured. It varies based on
+ * whether processors are in shared mode or dedicated mode.
+ * Get the notifier when CPU configuration is changed with DLPAR
+ * operation so that get the new target_credits (vas default capabilities)
+ * and then update the existing windows usage if needed.
+ */
+static int pseries_vas_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct of_reconfig_data *rd = data;
+ struct device_node *dn = rd->dn;
+ const __be32 *intserv = NULL;
+ int len, rc = 0;
+
+ if ((action == OF_RECONFIG_ATTACH_NODE) ||
+ (action == OF_RECONFIG_DETACH_NODE))
+ intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s",
+ &len);
+ /*
+ * Processor config is not changed
+ */
+ if (!intserv)
+ return NOTIFY_OK;
+
+ rc = vas_reconfig_capabilties(VAS_GZIP_DEF_FEAT_TYPE);
+ if (rc)
+ pr_err("Failed reconfig VAS capabilities with DLPAR\n");
+
+ return rc;
+}
+
+static struct notifier_block pseries_vas_nb = {
+ .notifier_call = pseries_vas_notifier,
+};
+
static int __init pseries_vas_init(void)
{
struct hv_vas_cop_feat_caps *hv_cop_caps;
goto out_cop;
}
+ if (copypaste_feat && firmware_has_feature(FW_FEATURE_LPAR))
+ of_reconfig_notifier_register(&pseries_vas_nb);
+
pr_info("GZIP feature is available\n");
out_cop:
projects / platform / kernel / linux-starfive.git / commitdiff