linux-dev/arch/powerpc/platforms/pseries/vas.c, branch linus/master

Merge branch 'fixes' into next

2022-05-18T14:11:51Z

Merge our fixes branch from this cycle. In particular this brings in a papr_scm.c change which a subsequent patch has a dependency on.

powerpc: fix typos in comments

2022-05-05T12:12:44Z

Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by: Julia Lawall Reviewed-by: Joel Stanley Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220430185654.5855-1-Julia.Lawall@inria.fr

powerpc/pseries/vas: Use QoS credits from the userspace

2022-05-04T12:00:47Z

The user can change the QoS credits dynamically with the management console interface which notifies OS with sysfs. After returning from the OS interface successfully, the management console updates the hypervisor. Since the VAS capabilities in the hypervisor is not updated when the OS gets the update, the kernel is using the old total credits value from the hypervisor. Fix this issue by using the new QoS credits from the userspace instead of depending on VAS capabilities from the hypervisor. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/76d156f8af1e03cc09369d68e0bfad0c40031bcc.camel@linux.ibm.com

powerpc/pseries/vas: Add VAS migration handler

2022-03-07T13:04:56Z

Since the VAS windows belong to the VAS hardware resource, the hypervisor expects the partition to close them on source partition and reopen them after the partition migrated on the destination machine. This handler is called before pseries_suspend() to close these windows and again invoked after migration. All active windows for both default and QoS types will be closed and mark them inactive and reopened after migration with this handler. During the migration, the user space receives paste instruction failure if it issues copy/paste on these inactive windows. The current migration implementation does not freeze the user space and applications can continue to open VAS windows while migration is in progress. So when the migration_in_progress flag is set, VAS open window API returns -EBUSY. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/05e45ff4f8babd2490ccb7ae923884f4aa21a7e5.camel@linux.ibm.com

powerpc/pseries/vas: Modify reconfig open/close functions for migration

2022-03-07T13:04:56Z

VAS is a hardware engine stays on the chip. So when the partition migrates, all VAS windows on the source system have to be closed and reopen them on the destination after migration. The kernel has to consider both DLPAR CPU and migration events to take action on VAS windows. So using VAS_WIN_NO_CRED_CLOSE and VAS_WIN_MIGRATE_CLOSE status bits and windows will be reopened after migration only after both status bits are cleared. This patch make changes to the current reconfig_open/close_windows functions to support migration: - Set VAS_WIN_MIGRATE_CLOSE to the window status when closes and reopen windows with the same status during resume. - Continue to close all windows even if deallocate HCALL failed (should not happen) since no way to stop migration with the current LPM implementation. - If the DLPAR CPU event happens while migration is in progress, set VAS_WIN_NO_CRED_CLOSE to the window status. Close window happens with the first event (migration or DLPAR) and Reopen window happens only with the last event (migration or DLPAR). Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0aad580387cb58379496b4cbbd7c5596e9ea70be.camel@linux.ibm.com

powerpc/pseries/vas: Define global hv_cop_caps struct

2022-03-07T13:04:56Z

The coprocessor capabilities struct is used to get default and QoS capabilities from the hypervisor during init, DLPAR event and migration. So instead of allocating this struct for each event, define global struct and reuse it which allows the migration code to avoid adding an error path. Also disable copy/paste feature flag if any capabilities HCALL is failed. Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Acked-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/57da6a270fcb9308cd57be7c88037029343080f7.camel@linux.ibm.com

powerpc/pseries/vas: Add 'update_total_credits' entry for QoS capabilities

2022-03-07T13:04:56Z

pseries supports two types of credits - Default (uses normal priority FIFO) and Qality of service (QoS uses high priority FIFO). The user decides the number of QoS credits and sets this value with HMC interface. The total credits for QoS capabilities can be changed dynamically with HMC interface which invokes drmgr to communicate to the kernel. This patch creats 'update_total_credits' entry for QoS capabilities so that drmgr command can write the new target QoS credits in sysfs. Instead of using this value, the kernel gets the new QoS capabilities from the hypervisor whenever update_total_credits is updated to make sure sync with the QoS target credits in the hypervisor. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/b01ef31a0f964686d00243e7de7f09c73c07e69e.camel@linux.ibm.com

powerpc/pseries/vas: sysfs interface to export capabilities

2022-03-07T13:04:56Z

The hypervisor provides the available VAS GZIP capabilities such as default or QoS window type and the target available credits in each type. This patch creates sysfs entries and exports the target, used and the available credits for each feature. This interface can be used by the user space to determine the credits usage or to set the target credits in the case of QoS type (for DLPAR). /sys/devices/vas/vas0/gzip/default_capabilities (default GZIP capabilities) nr_total_credits /* Total credits available. Can be /* changed with DLPAR operation */ nr_used_credits /* Used credits */ /sys/devices/vas/vas0/gzip/qos_capabilities (QoS GZIP capabilities) nr_total_credits nr_used_credits Signed-off-by: Haren Myneni Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/702d8b626ebfac2b52f4995eebeafe1c9a6fcb75.camel@linux.ibm.com

powerpc/pseries/vas: Reopen windows with DLPAR core add

2022-03-07T13:04:55Z

VAS windows can be closed in the hypervisor due to lost credits when the core is removed and the kernel gets fault for NX requests on these inactive windows. If the NX requests are issued on these inactive windows, OS gets page faults and the paste failure will be returned to the user space. If the lost credits are available later with core add, reopen these windows and set them active. Later when the OS sees page faults on these active windows, it creates mapping on the new paste address. Then the user space can continue to use these windows and send HW compression requests to NX successfully. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/d9f360e21355e6826142c81146acfa9b60bc7ecc.camel@linux.ibm.com

powerpc/pseries/vas: Close windows with DLPAR core removal

2022-03-07T13:04:55Z

The hypervisor assigns vas credits (windows) for each LPAR based on the number of cores configured in that system. The OS is expected to release credits when cores are removed, and may allocate more when cores are added. So there is a possibility of using excessive credits (windows) in the LPAR and the hypervisor expects the system to close the excessive windows so that NX load can be equally distributed across all LPARs in the system. When the OS closes the excessive windows in the hypervisor, it sets the window status inactive and invalidates window virtual address mapping. The user space receives paste instruction failure if any NX requests are issued on the inactive window. Then the user space can use with the available open windows or retry NX requests until this window active again. This patch also adds the notifier for core removal/add to close windows in the hypervisor if the system lost credits (core removal) and reopen windows in the hypervisor when the previously lost credits are available. Signed-off-by: Haren Myneni Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/108928f9c00a48cc6a722315d482d07cf66acf5a.camel@linux.ibm.com