diff options
Diffstat (limited to 'arch/powerpc/platforms')
| -rw-r--r-- | arch/powerpc/platforms/pseries/vas.c | 91 |
1 files changed, 90 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c index a297720bcdae..96178dd58adf 100644 --- a/arch/powerpc/platforms/pseries/vas.c +++ b/arch/powerpc/platforms/pseries/vas.c @@ -566,6 +566,88 @@ static int __init get_vas_capabilities(u8 feat, enum vas_cop_feat_type type, } /* + * 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) +{ + 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; + + /* + * 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. + */ + if (vcaps->nr_close_wins > creds) + mv_ents = vcaps->nr_close_wins - creds; + + list_for_each_entry_safe(win, tmp, &vcaps->list, win_list) { + if (!mv_ents) + break; + + mv_ents--; + } + + list_for_each_entry_safe_from(win, tmp, &vcaps->list, win_list) { + /* + * Nothing to do on this window if it is not closed + * with VAS_WIN_NO_CRED_CLOSE + */ + if (!(win->vas_win.status & VAS_WIN_NO_CRED_CLOSE)) + 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 &= ~VAS_WIN_NO_CRED_CLOSE; + 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. @@ -673,7 +755,14 @@ static int vas_reconfig_capabilties(u8 type) * 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) { + 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); + } else { /* * # active windows is more than new LPAR available * credits. So close the excessive windows. |