diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/vas.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/vas.c | 1084 |
1 files changed, 1084 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c new file mode 100644 index 000000000..5db806077 --- /dev/null +++ b/arch/powerpc/platforms/pseries/vas.c @@ -0,0 +1,1084 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2020-21 IBM Corp. + */ + +#define pr_fmt(fmt) "vas: " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/types.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/irqdomain.h> +#include <asm/machdep.h> +#include <asm/hvcall.h> +#include <asm/plpar_wrappers.h> +#include <asm/firmware.h> +#include <asm/vas.h> +#include "vas.h" + +#define VAS_INVALID_WIN_ADDRESS 0xFFFFFFFFFFFFFFFFul +#define VAS_DEFAULT_DOMAIN_ID 0xFFFFFFFFFFFFFFFFul +/* The hypervisor allows one credit per window right now */ +#define DEF_WIN_CREDS 1 + +static struct vas_all_caps caps_all; +static bool copypaste_feat; +static struct hv_vas_cop_feat_caps hv_cop_caps; + +static struct vas_caps vascaps[VAS_MAX_FEAT_TYPE]; +static DEFINE_MUTEX(vas_pseries_mutex); +static bool migration_in_progress; + +static long hcall_return_busy_check(long rc) +{ + /* Check if we are stalled for some time */ + if (H_IS_LONG_BUSY(rc)) { + msleep(get_longbusy_msecs(rc)); + rc = H_BUSY; + } else if (rc == H_BUSY) { + cond_resched(); + } + + return rc; +} + +/* + * Allocate VAS window hcall + */ +static int h_allocate_vas_window(struct pseries_vas_window *win, u64 *domain, + u8 wintype, u16 credits) +{ + long retbuf[PLPAR_HCALL9_BUFSIZE] = {0}; + long rc; + + do { + rc = plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, wintype, + credits, domain[0], domain[1], domain[2], + domain[3], domain[4], domain[5]); + + rc = hcall_return_busy_check(rc); + } while (rc == H_BUSY); + + if (rc == H_SUCCESS) { + if (win->win_addr == VAS_INVALID_WIN_ADDRESS) { + pr_err("H_ALLOCATE_VAS_WINDOW: COPY/PASTE is not supported\n"); + return -ENOTSUPP; + } + win->vas_win.winid = retbuf[0]; + win->win_addr = retbuf[1]; + win->complete_irq = retbuf[2]; + win->fault_irq = retbuf[3]; + return 0; + } + + pr_err("H_ALLOCATE_VAS_WINDOW error: %ld, wintype: %u, credits: %u\n", + rc, wintype, credits); + + return -EIO; +} + +/* + * Deallocate VAS window hcall. + */ +static int h_deallocate_vas_window(u64 winid) +{ + long rc; + + do { + rc = plpar_hcall_norets(H_DEALLOCATE_VAS_WINDOW, winid); + + rc = hcall_return_busy_check(rc); + } while (rc == H_BUSY); + + if (rc == H_SUCCESS) + return 0; + + pr_err("H_DEALLOCATE_VAS_WINDOW error: %ld, winid: %llu\n", + rc, winid); + return -EIO; +} + +/* + * Modify VAS window. + * After the window is opened with allocate window hcall, configure it + * with flags and LPAR PID before using. + */ +static int h_modify_vas_window(struct pseries_vas_window *win) +{ + long rc; + + /* + * AMR value is not supported in Linux VAS implementation. + * The hypervisor ignores it if 0 is passed. + */ + do { + rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW, + win->vas_win.winid, win->pid, 0, + VAS_MOD_WIN_FLAGS, 0); + + rc = hcall_return_busy_check(rc); + } while (rc == H_BUSY); + + if (rc == H_SUCCESS) + return 0; + + pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u pid %u\n", + rc, win->vas_win.winid, win->pid); + return -EIO; +} + +/* + * This hcall is used to determine the capabilities from the hypervisor. + * @hcall: H_QUERY_VAS_CAPABILITIES or H_QUERY_NX_CAPABILITIES + * @query_type: If 0 is passed, the hypervisor returns the overall + * capabilities which provides all feature(s) that are + * available. Then query the hypervisor to get the + * corresponding capabilities for the specific feature. + * Example: H_QUERY_VAS_CAPABILITIES provides VAS GZIP QoS + * and VAS GZIP Default capabilities. + * H_QUERY_NX_CAPABILITIES provides NX GZIP + * capabilities. + * @result: Return buffer to save capabilities. + */ +int h_query_vas_capabilities(const u64 hcall, u8 query_type, u64 result) +{ + long rc; + + rc = plpar_hcall_norets(hcall, query_type, result); + + if (rc == H_SUCCESS) + return 0; + + /* H_FUNCTION means HV does not support VAS so don't print an error */ + if (rc != H_FUNCTION) { + pr_err("%s error %ld, query_type %u, result buffer 0x%llx\n", + (hcall == H_QUERY_VAS_CAPABILITIES) ? + "H_QUERY_VAS_CAPABILITIES" : + "H_QUERY_NX_CAPABILITIES", + rc, query_type, result); + } + + return -EIO; +} +EXPORT_SYMBOL_GPL(h_query_vas_capabilities); + +/* + * hcall to get fault CRB from the hypervisor. + */ +static int h_get_nx_fault(u32 winid, u64 buffer) +{ + long rc; + + rc = plpar_hcall_norets(H_GET_NX_FAULT, winid, buffer); + + if (rc == H_SUCCESS) + return 0; + + pr_err("H_GET_NX_FAULT error: %ld, winid %u, buffer 0x%llx\n", + rc, winid, buffer); + return -EIO; + +} + +/* + * Handle the fault interrupt. + * When the fault interrupt is received for each window, query the + * hypervisor to get the fault CRB on the specific fault. Then + * process the CRB by updating CSB or send signal if the user space + * CSB is invalid. + * Note: The hypervisor forwards an interrupt for each fault request. + * So one fault CRB to process for each H_GET_NX_FAULT hcall. + */ +static irqreturn_t pseries_vas_fault_thread_fn(int irq, void *data) +{ + struct pseries_vas_window *txwin = data; + struct coprocessor_request_block crb; + struct vas_user_win_ref *tsk_ref; + int rc; + + while (atomic_read(&txwin->pending_faults)) { + rc = h_get_nx_fault(txwin->vas_win.winid, (u64)virt_to_phys(&crb)); + if (!rc) { + tsk_ref = &txwin->vas_win.task_ref; + vas_dump_crb(&crb); + vas_update_csb(&crb, tsk_ref); + } + atomic_dec(&txwin->pending_faults); + } + + return IRQ_HANDLED; +} + +/* + * irq_default_primary_handler() can be used only with IRQF_ONESHOT + * which disables IRQ before executing the thread handler and enables + * it after. But this disabling interrupt sets the VAS IRQ OFF + * state in the hypervisor. If the NX generates fault interrupt + * during this window, the hypervisor will not deliver this + * interrupt to the LPAR. So use VAS specific IRQ handler instead + * of calling the default primary handler. + */ +static irqreturn_t pseries_vas_irq_handler(int irq, void *data) +{ + struct pseries_vas_window *txwin = data; + + /* + * The thread hanlder will process this interrupt if it is + * already running. + */ + atomic_inc(&txwin->pending_faults); + + return IRQ_WAKE_THREAD; +} + +/* + * Allocate window and setup IRQ mapping. + */ +static int allocate_setup_window(struct pseries_vas_window *txwin, + u64 *domain, u8 wintype) +{ + int rc; + + rc = h_allocate_vas_window(txwin, domain, wintype, DEF_WIN_CREDS); + if (rc) + return rc; + /* + * On PowerVM, the hypervisor setup and forwards the fault + * interrupt per window. So the IRQ setup and fault handling + * will be done for each open window separately. + */ + txwin->fault_virq = irq_create_mapping(NULL, txwin->fault_irq); + if (!txwin->fault_virq) { + pr_err("Failed irq mapping %d\n", txwin->fault_irq); + rc = -EINVAL; + goto out_win; + } + + txwin->name = kasprintf(GFP_KERNEL, "vas-win-%d", + txwin->vas_win.winid); + if (!txwin->name) { + rc = -ENOMEM; + goto out_irq; + } + + rc = request_threaded_irq(txwin->fault_virq, + pseries_vas_irq_handler, + pseries_vas_fault_thread_fn, 0, + txwin->name, txwin); + if (rc) { + pr_err("VAS-Window[%d]: Request IRQ(%u) failed with %d\n", + txwin->vas_win.winid, txwin->fault_virq, rc); + goto out_free; + } + + txwin->vas_win.wcreds_max = DEF_WIN_CREDS; + + return 0; +out_free: + kfree(txwin->name); +out_irq: + irq_dispose_mapping(txwin->fault_virq); +out_win: + h_deallocate_vas_window(txwin->vas_win.winid); + return rc; +} + +static inline void free_irq_setup(struct pseries_vas_window *txwin) +{ + free_irq(txwin->fault_virq, txwin); + kfree(txwin->name); + irq_dispose_mapping(txwin->fault_virq); +} + +static struct vas_window *vas_allocate_window(int vas_id, u64 flags, + enum vas_cop_type cop_type) +{ + long domain[PLPAR_HCALL9_BUFSIZE] = {VAS_DEFAULT_DOMAIN_ID}; + struct vas_cop_feat_caps *cop_feat_caps; + struct vas_caps *caps; + struct pseries_vas_window *txwin; + int rc; + + txwin = kzalloc(sizeof(*txwin), GFP_KERNEL); + if (!txwin) + return ERR_PTR(-ENOMEM); + + /* + * A VAS window can have many credits which means that many + * requests can be issued simultaneously. But the hypervisor + * restricts one credit per window. + * The hypervisor introduces 2 different types of credits: + * Default credit type (Uses normal priority FIFO): + * A limited number of credits are assigned to partitions + * based on processor entitlement. But these credits may be + * over-committed on a system depends on whether the CPUs + * are in shared or dedicated modes - that is, more requests + * may be issued across the system than NX can service at + * once which can result in paste command failure (RMA_busy). + * Then the process has to resend requests or fall-back to + * SW compression. + * Quality of Service (QoS) credit type (Uses high priority FIFO): + * To avoid NX HW contention, the system admins can assign + * QoS credits for each LPAR so that this partition is + * guaranteed access to NX resources. These credits are + * assigned to partitions via the HMC. + * Refer PAPR for more information. + * + * Allocate window with QoS credits if user requested. Otherwise + * default credits are used. + */ + if (flags & VAS_TX_WIN_FLAG_QOS_CREDIT) + caps = &vascaps[VAS_GZIP_QOS_FEAT_TYPE]; + else + caps = &vascaps[VAS_GZIP_DEF_FEAT_TYPE]; + + cop_feat_caps = &caps->caps; + + if (atomic_inc_return(&cop_feat_caps->nr_used_credits) > + atomic_read(&cop_feat_caps->nr_total_credits)) { + pr_err_ratelimited("Credits are not available to allocate window\n"); + rc = -EINVAL; + goto out; + } + + if (vas_id == -1) { + /* + * The user space is requesting to allocate a window on + * a VAS instance where the process is executing. + * On PowerVM, domain values are passed to the hypervisor + * to select VAS instance. Useful if the process is + * affinity to NUMA node. + * The hypervisor selects VAS instance if + * VAS_DEFAULT_DOMAIN_ID (-1) is passed for domain values. + * The h_allocate_vas_window hcall is defined to take a + * domain values as specified by h_home_node_associativity, + * So no unpacking needs to be done. + */ + rc = plpar_hcall9(H_HOME_NODE_ASSOCIATIVITY, domain, + VPHN_FLAG_VCPU, hard_smp_processor_id()); + if (rc != H_SUCCESS) { + pr_err("H_HOME_NODE_ASSOCIATIVITY error: %d\n", rc); + goto out; + } + } + + txwin->pid = mfspr(SPRN_PID); + + /* + * Allocate / Deallocate window hcalls and setup / free IRQs + * have to be protected with mutex. + * Open VAS window: Allocate window hcall and setup IRQ + * Close VAS window: Deallocate window hcall and free IRQ + * The hypervisor waits until all NX requests are + * completed before closing the window. So expects OS + * to handle NX faults, means IRQ can be freed only + * after the deallocate window hcall is returned. + * So once the window is closed with deallocate hcall before + * the IRQ is freed, it can be assigned to new allocate + * hcall with the same fault IRQ by the hypervisor. It can + * result in setup IRQ fail for the new window since the + * same fault IRQ is not freed by the OS before. + */ + mutex_lock(&vas_pseries_mutex); + if (migration_in_progress) + rc = -EBUSY; + else + rc = allocate_setup_window(txwin, (u64 *)&domain[0], + cop_feat_caps->win_type); + mutex_unlock(&vas_pseries_mutex); + if (rc) + goto out; + + /* + * Modify window and it is ready to use. + */ + rc = h_modify_vas_window(txwin); + if (!rc) + rc = get_vas_user_win_ref(&txwin->vas_win.task_ref); + if (rc) + goto out_free; + + txwin->win_type = cop_feat_caps->win_type; + mutex_lock(&vas_pseries_mutex); + /* + * 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); + + put_vas_user_win_ref(&txwin->vas_win.task_ref); + rc = -EBUSY; + pr_err_ratelimited("No credit is available to allocate window\n"); + +out_free: + /* + * Window is not operational. Free IRQ before closing + * window so that do not have to hold mutex. + */ + free_irq_setup(txwin); + h_deallocate_vas_window(txwin->vas_win.winid); +out: + atomic_dec(&cop_feat_caps->nr_used_credits); + kfree(txwin); + return ERR_PTR(rc); +} + +static u64 vas_paste_address(struct vas_window *vwin) +{ + struct pseries_vas_window *win; + + win = container_of(vwin, struct pseries_vas_window, vas_win); + return win->win_addr; +} + +static int deallocate_free_window(struct pseries_vas_window *win) +{ + int rc = 0; + + /* + * The hypervisor waits for all requests including faults + * are processed before closing the window - Means all + * credits have to be returned. In the case of fault + * request, a credit is returned after OS issues + * H_GET_NX_FAULT hcall. + * So free IRQ after executing H_DEALLOCATE_VAS_WINDOW + * hcall. + */ + rc = h_deallocate_vas_window(win->vas_win.winid); + if (!rc) + free_irq_setup(win); + + return rc; +} + +static int vas_deallocate_window(struct vas_window *vwin) +{ + struct pseries_vas_window *win; + struct vas_cop_feat_caps *caps; + int rc = 0; + + if (!vwin) + return -EINVAL; + + win = container_of(vwin, struct pseries_vas_window, vas_win); + + /* Should not happen */ + if (win->win_type >= VAS_MAX_FEAT_TYPE) { + pr_err("Window (%u): Invalid window type %u\n", + vwin->winid, win->win_type); + return -EINVAL; + } + + caps = &vascaps[win->win_type].caps; + mutex_lock(&vas_pseries_mutex); + /* + * VAS window is already closed in the hypervisor when + * lost the credit or with migration. 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) && + !(win->vas_win.status & VAS_WIN_MIGRATE_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); + + mm_context_remove_vas_window(vwin->task_ref.mm); + put_vas_user_win_ref(&vwin->task_ref); + + kfree(win); + return 0; +} + +static const struct vas_user_win_ops vops_pseries = { + .open_win = vas_allocate_window, /* Open and configure window */ + .paste_addr = vas_paste_address, /* To do copy/paste */ + .close_win = vas_deallocate_window, /* Close window */ +}; + +/* + * Supporting only nx-gzip coprocessor type now, but this API code + * extended to other coprocessor types later. + */ +int vas_register_api_pseries(struct module *mod, enum vas_cop_type cop_type, + const char *name) +{ + if (!copypaste_feat) + return -ENOTSUPP; + + return vas_register_coproc_api(mod, cop_type, name, &vops_pseries); +} +EXPORT_SYMBOL_GPL(vas_register_api_pseries); + +void vas_unregister_api_pseries(void) +{ + vas_unregister_coproc_api(); +} +EXPORT_SYMBOL_GPL(vas_unregister_api_pseries); + +/* + * Get the specific capabilities based on the feature type. + * Right now supports GZIP default and GZIP QoS capabilities. + */ +static int __init get_vas_capabilities(u8 feat, enum vas_cop_feat_type type, + struct hv_vas_cop_feat_caps *hv_caps) +{ + struct vas_cop_feat_caps *caps; + struct vas_caps *vcaps; + int rc = 0; + + vcaps = &vascaps[type]; + 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, + (u64)virt_to_phys(hv_caps)); + if (rc) + return rc; + + caps->user_mode = hv_caps->user_mode; + if (!(caps->user_mode & VAS_COPY_PASTE_USER_MODE)) { + pr_err("User space COPY/PASTE is not supported\n"); + return -ENOTSUPP; + } + + caps->descriptor = be64_to_cpu(hv_caps->descriptor); + caps->win_type = hv_caps->win_type; + if (caps->win_type >= VAS_MAX_FEAT_TYPE) { + pr_err("Unsupported window type %u\n", caps->win_type); + return -EINVAL; + } + caps->max_lpar_creds = be16_to_cpu(hv_caps->max_lpar_creds); + caps->max_win_creds = be16_to_cpu(hv_caps->max_win_creds); + atomic_set(&caps->nr_total_credits, + be16_to_cpu(hv_caps->target_lpar_creds)); + if (feat == VAS_GZIP_DEF_FEAT) { + caps->def_lpar_creds = be16_to_cpu(hv_caps->def_lpar_creds); + + if (caps->max_win_creds < DEF_WIN_CREDS) { + pr_err("Window creds(%u) > max allowed window creds(%u)\n", + DEF_WIN_CREDS, caps->max_win_creds); + return -EINVAL; + } + } + + rc = sysfs_add_vas_caps(caps); + if (rc) + return rc; + + copypaste_feat = true; + + return 0; +} + +/* + * VAS windows can be closed due to lost credits when the core is + * removed. So reopen them if credits are available due to DLPAR + * core add and set the window active status. When NX sees the page + * fault on the unmapped paste address, the kernel handles the fault + * by setting the remapping to new paste address if the window is + * active. + */ +static int reconfig_open_windows(struct vas_caps *vcaps, int creds, + bool migrate) +{ + long domain[PLPAR_HCALL9_BUFSIZE] = {VAS_DEFAULT_DOMAIN_ID}; + struct vas_cop_feat_caps *caps = &vcaps->caps; + struct pseries_vas_window *win = NULL, *tmp; + int rc, mv_ents = 0; + int flag; + + /* + * Nothing to do if there are no closed windows. + */ + if (!vcaps->nr_close_wins) + return 0; + + /* + * For the core removal, the hypervisor reduces the credits + * assigned to the LPAR and the kernel closes VAS windows + * in the hypervisor depends on reduced credits. The kernel + * uses LIFO (the last windows that are opened will be closed + * first) and expects to open in the same order when credits + * are available. + * For example, 40 windows are closed when the LPAR lost 2 cores + * (dedicated). If 1 core is added, this LPAR can have 20 more + * credits. It means the kernel can reopen 20 windows. So move + * 20 entries in the VAS windows lost and reopen next 20 windows. + * For partition migration, reopen all windows that are closed + * during resume. + */ + if ((vcaps->nr_close_wins > creds) && !migrate) + mv_ents = vcaps->nr_close_wins - creds; + + list_for_each_entry_safe(win, tmp, &vcaps->list, win_list) { + if (!mv_ents) + break; + + mv_ents--; + } + + /* + * Open windows if they are closed only with migration or + * DLPAR (lost credit) before. + */ + if (migrate) + flag = VAS_WIN_MIGRATE_CLOSE; + else + flag = VAS_WIN_NO_CRED_CLOSE; + + list_for_each_entry_safe_from(win, tmp, &vcaps->list, win_list) { + /* + * This window is closed with DLPAR and migration events. + * So reopen the window with the last event. + * The user space is not suspended with the current + * migration notifier. So the user space can issue DLPAR + * CPU hotplug while migration in progress. In this case + * this window will be opened with the last event. + */ + if ((win->vas_win.status & VAS_WIN_NO_CRED_CLOSE) && + (win->vas_win.status & VAS_WIN_MIGRATE_CLOSE)) { + win->vas_win.status &= ~flag; + continue; + } + + /* + * Nothing to do on this window if it is not closed + * with this flag + */ + if (!(win->vas_win.status & flag)) + continue; + + rc = allocate_setup_window(win, (u64 *)&domain[0], + caps->win_type); + if (rc) + return rc; + + rc = h_modify_vas_window(win); + if (rc) + goto out; + + mutex_lock(&win->vas_win.task_ref.mmap_mutex); + /* + * Set window status to active + */ + win->vas_win.status &= ~flag; + mutex_unlock(&win->vas_win.task_ref.mmap_mutex); + win->win_type = caps->win_type; + if (!--vcaps->nr_close_wins) + break; + } + + return 0; +out: + /* + * Window modify HCALL failed. So close the window to the + * hypervisor and return. + */ + free_irq_setup(win); + h_deallocate_vas_window(win->vas_win.winid); + return rc; +} + +/* + * 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, + bool migrate) +{ + struct pseries_vas_window *win, *tmp; + struct vas_user_win_ref *task_ref; + struct vm_area_struct *vma; + int rc = 0, flag; + + if (migrate) + flag = VAS_WIN_MIGRATE_CLOSE; + else + flag = VAS_WIN_NO_CRED_CLOSE; + + list_for_each_entry_safe(win, tmp, &vcap->list, win_list) { + /* + * This window is already closed due to lost credit + * or for migration before. Go for next window. + * For migration, nothing to do since this window + * closed for DLPAR and will be reopened even on + * the destination system with other DLPAR operation. + */ + if ((win->vas_win.status & VAS_WIN_MIGRATE_CLOSE) || + (win->vas_win.status & VAS_WIN_NO_CRED_CLOSE)) { + win->vas_win.status |= flag; + continue; + } + + task_ref = &win->vas_win.task_ref; + /* + * VAS mmap (coproc_mmap()) and its fault handler + * (vas_mmap_fault()) are called after holding mmap lock. + * So hold mmap mutex after mmap_lock to avoid deadlock. + */ + mmap_write_lock(task_ref->mm); + 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 |= flag; + + /* + * 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); + + mutex_unlock(&task_ref->mmap_mutex); + mmap_write_unlock(task_ref->mm); + /* + * 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); + /* + * This failure is from the hypervisor. + * No way to stop migration for these failures. + * So ignore error and continue closing other windows. + */ + if (rc && !migrate) + return rc; + + vcap->nr_close_wins++; + + /* + * For migration, do not depend on lpar_creds in case if + * mismatch with the hypervisor value (should not happen). + * So close all active windows in the list and will be + * reopened windows based on the new lpar_creds on the + * destination system during resume. + */ + if (!migrate && !--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. + */ +int vas_reconfig_capabilties(u8 type, int new_nr_creds) +{ + struct vas_cop_feat_caps *caps; + int old_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; + + mutex_lock(&vas_pseries_mutex); + + 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 + * increased with DLPAR operation. Means some windows have to be + * closed / reopened. Hold the vas_pseries_mutex so that the + * user space can not open new windows. + */ + if (old_nr_creds < new_nr_creds) { + /* + * If the existing target credits is less than the new + * target, reopen windows if they are closed due to + * the previous DLPAR (core removal). + */ + rc = reconfig_open_windows(vcaps, new_nr_creds - old_nr_creds, + false); + } else { + /* + * # 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, + false); + } + + mutex_unlock(&vas_pseries_mutex); + return rc; +} + +int pseries_vas_dlpar_cpu(void) +{ + int new_nr_creds, rc; + + /* + * NX-GZIP is not enabled. Nothing to do for DLPAR event + */ + if (!copypaste_feat) + return 0; + + + rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, + vascaps[VAS_GZIP_DEF_FEAT_TYPE].feat, + (u64)virt_to_phys(&hv_cop_caps)); + if (!rc) { + new_nr_creds = be16_to_cpu(hv_cop_caps.target_lpar_creds); + rc = vas_reconfig_capabilties(VAS_GZIP_DEF_FEAT_TYPE, new_nr_creds); + } + + if (rc) + pr_err("Failed reconfig VAS capabilities with DLPAR\n"); + + 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; + + /* + * For shared CPU partition, the hypervisor assigns total credits + * based on entitled core capacity. So updating VAS windows will + * be called from lparcfg_write(). + */ + if (is_shared_processor()) + return NOTIFY_OK; + + 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; + + return pseries_vas_dlpar_cpu(); +} + +static struct notifier_block pseries_vas_nb = { + .notifier_call = pseries_vas_notifier, +}; + +/* + * For LPM, all windows have to be closed on the source partition + * before migration and reopen them on the destination partition + * after migration. So closing windows during suspend and + * reopen them during resume. + */ +int vas_migration_handler(int action) +{ + struct vas_cop_feat_caps *caps; + int old_nr_creds, new_nr_creds = 0; + struct vas_caps *vcaps; + int i, rc = 0; + + /* + * NX-GZIP is not enabled. Nothing to do for migration. + */ + if (!copypaste_feat) + return rc; + + mutex_lock(&vas_pseries_mutex); + + if (action == VAS_SUSPEND) + migration_in_progress = true; + else + migration_in_progress = false; + + for (i = 0; i < VAS_MAX_FEAT_TYPE; i++) { + vcaps = &vascaps[i]; + caps = &vcaps->caps; + old_nr_creds = atomic_read(&caps->nr_total_credits); + + rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, + vcaps->feat, + (u64)virt_to_phys(&hv_cop_caps)); + if (!rc) { + new_nr_creds = be16_to_cpu(hv_cop_caps.target_lpar_creds); + /* + * Should not happen. But incase print messages, close + * all windows in the list during suspend and reopen + * windows based on new lpar_creds on the destination + * system. + */ + if (old_nr_creds != new_nr_creds) { + pr_err("Target credits mismatch with the hypervisor\n"); + pr_err("state(%d): lpar creds: %d HV lpar creds: %d\n", + action, old_nr_creds, new_nr_creds); + pr_err("Used creds: %d, Active creds: %d\n", + atomic_read(&caps->nr_used_credits), + vcaps->nr_open_windows - vcaps->nr_close_wins); + } + } else { + pr_err("state(%d): Get VAS capabilities failed with %d\n", + action, rc); + /* + * We can not stop migration with the current lpm + * implementation. So continue closing all windows in + * the list (during suspend) and return without + * opening windows (during resume) if VAS capabilities + * HCALL failed. + */ + if (action == VAS_RESUME) + goto out; + } + + switch (action) { + case VAS_SUSPEND: + rc = reconfig_close_windows(vcaps, vcaps->nr_open_windows, + true); + break; + case VAS_RESUME: + atomic_set(&caps->nr_total_credits, new_nr_creds); + rc = reconfig_open_windows(vcaps, new_nr_creds, true); + break; + default: + /* should not happen */ + pr_err("Invalid migration action %d\n", action); + rc = -EINVAL; + goto out; + } + + /* + * Ignore errors during suspend and return for resume. + */ + if (rc && (action == VAS_RESUME)) + goto out; + } + +out: + mutex_unlock(&vas_pseries_mutex); + return rc; +} + +static int __init pseries_vas_init(void) +{ + struct hv_vas_all_caps *hv_caps; + int rc = 0; + + /* + * Linux supports user space COPY/PASTE only with Radix + */ + if (!radix_enabled()) { + copypaste_feat = false; + pr_err("API is supported only with radix page tables\n"); + return -ENOTSUPP; + } + + hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL); + if (!hv_caps) + return -ENOMEM; + /* + * Get VAS overall capabilities by passing 0 to feature type. + */ + rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, 0, + (u64)virt_to_phys(hv_caps)); + if (rc) + goto out; + + caps_all.descriptor = be64_to_cpu(hv_caps->descriptor); + caps_all.feat_type = be64_to_cpu(hv_caps->feat_type); + + sysfs_pseries_vas_init(&caps_all); + + /* + * QOS capabilities available + */ + if (caps_all.feat_type & VAS_GZIP_QOS_FEAT_BIT) { + rc = get_vas_capabilities(VAS_GZIP_QOS_FEAT, + VAS_GZIP_QOS_FEAT_TYPE, &hv_cop_caps); + + if (rc) + goto out; + } + /* + * Default capabilities available + */ + if (caps_all.feat_type & VAS_GZIP_DEF_FEAT_BIT) + rc = get_vas_capabilities(VAS_GZIP_DEF_FEAT, + VAS_GZIP_DEF_FEAT_TYPE, &hv_cop_caps); + + if (!rc && copypaste_feat) { + if (firmware_has_feature(FW_FEATURE_LPAR)) + of_reconfig_notifier_register(&pseries_vas_nb); + + pr_info("GZIP feature is available\n"); + } else { + /* + * Should not happen, but only when get default + * capabilities HCALL failed. So disable copy paste + * feature. + */ + copypaste_feat = false; + } + +out: + kfree(hv_caps); + return rc; +} +machine_device_initcall(pseries, pseries_vas_init); |