From 465dda9d320d1cb9424f1015b0520ec4c4f0d279 Mon Sep 17 00:00:00 2001 From: Haren Myneni Date: Thu, 22 Sep 2022 01:27:07 -0700 Subject: [PATCH] powerpc/pseries: Move vas_migration_handler early during migration When the migration is initiated, the hypervisor changes VAS mappings as part of pre-migration event. Then the OS gets the migration event which closes all VAS windows before the migration starts. NX generates continuous faults until windows are closed and the user space can not differentiate these NX faults coming from the actual migration. So to reduce this time window, close VAS windows first in pseries_migrate_partition(). Signed-off-by: Haren Myneni Reviewed-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/d8efade91dda831c9ed4abb226dab627da594c5f.camel@linux.ibm.com --- arch/powerpc/platforms/pseries/mobility.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index c92c78332303..634fac5db3f9 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -740,11 +740,19 @@ static int pseries_migrate_partition(u64 handle) #ifdef CONFIG_PPC_WATCHDOG factor = nmi_wd_lpm_factor; #endif + /* + * When the migration is initiated, the hypervisor changes VAS + * mappings to prepare before OS gets the notification and + * closes all VAS windows. NX generates continuous faults during + * this time and the user space can not differentiate these + * faults from the migration event. So reduce this time window + * by closing VAS windows at the beginning of this function. + */ + vas_migration_handler(VAS_SUSPEND); + ret = wait_for_vasi_session_suspending(handle); if (ret) - return ret; - - vas_migration_handler(VAS_SUSPEND); + goto out; if (factor) watchdog_nmi_set_timeout_pct(factor); @@ -765,6 +773,7 @@ static int pseries_migrate_partition(u64 handle) if (factor) watchdog_nmi_set_timeout_pct(0); +out: vas_migration_handler(VAS_RESUME); return ret;