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authorLinus Torvalds <torvalds@linux-foundation.org>2023-12-17 17:50:00 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2023-12-17 17:50:00 +0100
commit5ef3720d91285f7ebc49d17366b366818516b768 (patch)
treecefa4034eeaf698c2bed05b4f78fb9c62f9375f6 /arch
parentMerge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/... (diff)
parentMAINTAINERS: powerpc: Add Aneesh & Naveen (diff)
downloadlinux-5ef3720d91285f7ebc49d17366b366818516b768.tar.xz
linux-5ef3720d91285f7ebc49d17366b366818516b768.zip
Merge tag 'powerpc-6.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman: - Fix a bug where heavy VAS (accelerator) usage could race with partition migration and prevent the migration from completing. - Update MAINTAINERS to add Aneesh & Naveen. Thanks to Haren Myneni. * tag 'powerpc-6.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: MAINTAINERS: powerpc: Add Aneesh & Naveen powerpc/pseries/vas: Migration suspend waits for no in-progress open windows
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/platforms/pseries/vas.c51
-rw-r--r--arch/powerpc/platforms/pseries/vas.h2
2 files changed, 46 insertions, 7 deletions
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index b1f25bac280b..71d52a670d95 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -385,11 +385,15 @@ 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;
@@ -404,8 +408,17 @@ 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
@@ -413,9 +426,11 @@ 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;
@@ -433,6 +448,12 @@ 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);
@@ -937,14 +958,14 @@ 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
@@ -990,12 +1011,27 @@ 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 */
@@ -1011,8 +1047,9 @@ 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;
}
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 7115043ec488..45567cd13178 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -91,6 +91,8 @@ struct vas_cop_feat_caps {
struct vas_caps {
struct vas_cop_feat_caps caps;
struct list_head list; /* List of open windows */
+ int nr_open_wins_progress; /* Number of open windows in */
+ /* progress. Used in migration */
int nr_close_wins; /* closed windows in the hypervisor for DLPAR */
int nr_open_windows; /* Number of successful open windows */
u8 feat; /* Feature type */