diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/vas.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/vas.c | 91 |
1 files changed, 77 insertions, 14 deletions
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c index 513180467562..c25eb1a38185 100644 --- a/arch/powerpc/platforms/pseries/vas.c +++ b/arch/powerpc/platforms/pseries/vas.c @@ -17,6 +17,7 @@ #include <asm/hvcall.h> #include <asm/plpar_wrappers.h> #include <asm/firmware.h> +#include <asm/vphn.h> #include <asm/vas.h> #include "vas.h" @@ -37,7 +38,27 @@ 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)); + unsigned int ms; + /* + * Allocate, Modify and Deallocate HCALLs returns + * H_LONG_BUSY_ORDER_1_MSEC or H_LONG_BUSY_ORDER_10_MSEC + * for the long delay. So the sleep time should always + * be either 1 or 10msecs, but in case if the HCALL + * returns the long delay > 10 msecs, clamp the sleep + * time to 10msecs. + */ + ms = clamp(get_longbusy_msecs(rc), 1, 10); + + /* + * msleep() will often sleep at least 20 msecs even + * though the hypervisor suggests that the OS reissue + * HCALLs after 1 or 10msecs. Also the delay hint from + * the HCALL is just a suggestion. So OK to pause for + * less time than the hinted delay. Use usleep_range() + * to ensure we don't sleep much longer than actually + * needed. + */ + usleep_range(ms * (USEC_PER_MSEC / 10), ms * USEC_PER_MSEC); rc = H_BUSY; } else if (rc == H_BUSY) { cond_resched(); @@ -227,7 +248,7 @@ 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 + * The thread handler will process this interrupt if it is * already running. */ atomic_inc(&txwin->pending_faults); @@ -340,7 +361,7 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, if (atomic_inc_return(&cop_feat_caps->nr_used_credits) > atomic_read(&cop_feat_caps->nr_total_credits)) { - pr_err("Credits are not available to allocate window\n"); + pr_err_ratelimited("Credits are not available to allocate window\n"); rc = -EINVAL; goto out; } @@ -384,11 +405,15 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, * same fault IRQ is not freed by the OS before. */ mutex_lock(&vas_pseries_mutex); - if (migration_in_progress) + if (migration_in_progress) { rc = -EBUSY; - else + } else { rc = allocate_setup_window(txwin, (u64 *)&domain[0], cop_feat_caps->win_type); + if (!rc) + caps->nr_open_wins_progress++; + } + mutex_unlock(&vas_pseries_mutex); if (rc) goto out; @@ -403,8 +428,17 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, goto out_free; txwin->win_type = cop_feat_caps->win_type; - mutex_lock(&vas_pseries_mutex); + /* + * The migration SUSPEND thread sets migration_in_progress and + * closes all open windows from the list. But the window is + * added to the list after open and modify HCALLs. So possible + * that migration_in_progress is set before modify HCALL which + * may cause some windows are still open when the hypervisor + * initiates the migration. + * So checks the migration_in_progress flag again and close all + * open windows. + * * 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 @@ -412,9 +446,11 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, * after the existing windows are reopened when credits are * available. */ - if (!caps->nr_close_wins) { + mutex_lock(&vas_pseries_mutex); + if (!caps->nr_close_wins && !migration_in_progress) { list_add(&txwin->win_list, &caps->list); caps->nr_open_windows++; + caps->nr_open_wins_progress--; mutex_unlock(&vas_pseries_mutex); vas_user_win_add_mm_context(&txwin->vas_win.task_ref); return &txwin->vas_win; @@ -423,7 +459,7 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, put_vas_user_win_ref(&txwin->vas_win.task_ref); rc = -EBUSY; - pr_err("No credit is available to allocate window\n"); + pr_err_ratelimited("No credit is available to allocate window\n"); out_free: /* @@ -432,6 +468,12 @@ out_free: */ free_irq_setup(txwin); h_deallocate_vas_window(txwin->vas_win.winid); + /* + * Hold mutex and reduce nr_open_wins_progress counter. + */ + mutex_lock(&vas_pseries_mutex); + caps->nr_open_wins_progress--; + mutex_unlock(&vas_pseries_mutex); out: atomic_dec(&cop_feat_caps->nr_used_credits); kfree(txwin); @@ -507,8 +549,8 @@ static int vas_deallocate_window(struct vas_window *vwin) vascaps[win->win_type].nr_open_windows--; mutex_unlock(&vas_pseries_mutex); - put_vas_user_win_ref(&vwin->task_ref); mm_context_remove_vas_window(vwin->task_ref.mm); + put_vas_user_win_ref(&vwin->task_ref); kfree(win); return 0; @@ -744,6 +786,12 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds, } 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; /* @@ -752,7 +800,6 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds, */ win->vas_win.status |= flag; - 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. @@ -762,8 +809,8 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds, if (vma) zap_vma_pages(vma); - mmap_write_unlock(task_ref->mm); 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 @@ -931,14 +978,14 @@ int vas_migration_handler(int action) struct vas_caps *vcaps; int i, rc = 0; + pr_info("VAS migration event %d\n", action); + /* * 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 @@ -984,12 +1031,27 @@ int vas_migration_handler(int action) switch (action) { case VAS_SUSPEND: + mutex_lock(&vas_pseries_mutex); rc = reconfig_close_windows(vcaps, vcaps->nr_open_windows, true); + /* + * Windows are included in the list after successful + * open. So wait for closing these in-progress open + * windows in vas_allocate_window() which will be + * done if the migration_in_progress is set. + */ + while (vcaps->nr_open_wins_progress) { + mutex_unlock(&vas_pseries_mutex); + msleep(10); + mutex_lock(&vas_pseries_mutex); + } + mutex_unlock(&vas_pseries_mutex); break; case VAS_RESUME: + mutex_lock(&vas_pseries_mutex); atomic_set(&caps->nr_total_credits, new_nr_creds); rc = reconfig_open_windows(vcaps, new_nr_creds, true); + mutex_unlock(&vas_pseries_mutex); break; default: /* should not happen */ @@ -1005,8 +1067,9 @@ int vas_migration_handler(int action) goto out; } + pr_info("VAS migration event (%d) successful\n", action); + out: - mutex_unlock(&vas_pseries_mutex); return rc; } |