[PATCH V7 05/14] powerpc/vas: Setup fault window per VAS instance
Haren Myneni
haren at linux.ibm.com
Sat Mar 7 07:14:17 AEDT 2020
Setup fault window for each VAS instance. When NX gets a fault on
request buffer, write fault CRBs in the corresponding fault FIFO and
then sends an interrupt to the OS.
Signed-off-by: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren at linux.ibm.com>
---
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/vas-fault.c | 77 +++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/vas-window.c | 4 +-
arch/powerpc/platforms/powernv/vas.c | 20 ++++++++
arch/powerpc/platforms/powernv/vas.h | 16 ++++++
5 files changed, 116 insertions(+), 3 deletions(-)
create mode 100644 arch/powerpc/platforms/powernv/vas-fault.c
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index c0f8120..395789f 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -17,7 +17,7 @@ obj-$(CONFIG_MEMORY_FAILURE) += opal-memory-errors.o
obj-$(CONFIG_OPAL_PRD) += opal-prd.o
obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
obj-$(CONFIG_PPC_MEMTRACE) += memtrace.o
-obj-$(CONFIG_PPC_VAS) += vas.o vas-window.o vas-debug.o
+obj-$(CONFIG_PPC_VAS) += vas.o vas-window.o vas-debug.o vas-fault.o
obj-$(CONFIG_OCXL_BASE) += ocxl.o
obj-$(CONFIG_SCOM_DEBUGFS) += opal-xscom.o
obj-$(CONFIG_PPC_SECURE_BOOT) += opal-secvar.o
diff --git a/arch/powerpc/platforms/powernv/vas-fault.c b/arch/powerpc/platforms/powernv/vas-fault.c
new file mode 100644
index 0000000..4044998
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/vas-fault.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * VAS Fault handling.
+ * Copyright 2019, IBM Corporation
+ */
+
+#define pr_fmt(fmt) "vas: " fmt
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/kthread.h>
+#include <asm/icswx.h>
+
+#include "vas.h"
+
+/*
+ * The maximum FIFO size for fault window can be 8MB
+ * (VAS_RX_FIFO_SIZE_MAX). Using 4MB FIFO since each VAS
+ * instance will be having fault window.
+ * 8MB FIFO can be used if expects more faults for each VAS
+ * instance.
+ */
+#define VAS_FAULT_WIN_FIFO_SIZE (4 << 20)
+
+/*
+ * Fault window is opened per VAS instance. NX pastes fault CRB in fault
+ * FIFO upon page faults.
+ */
+int vas_setup_fault_window(struct vas_instance *vinst)
+{
+ struct vas_rx_win_attr attr;
+
+ vinst->fault_fifo_size = VAS_FAULT_WIN_FIFO_SIZE;
+ vinst->fault_fifo = kzalloc(vinst->fault_fifo_size, GFP_KERNEL);
+ if (!vinst->fault_fifo) {
+ pr_err("Unable to alloc %d bytes for fault_fifo\n",
+ vinst->fault_fifo_size);
+ return -ENOMEM;
+ }
+
+ /*
+ * Invalidate all CRB entries. NX pastes valid entry for each fault.
+ */
+ memset(vinst->fault_fifo, FIFO_INVALID_ENTRY, vinst->fault_fifo_size);
+ vas_init_rx_win_attr(&attr, VAS_COP_TYPE_FAULT);
+
+ attr.rx_fifo_size = vinst->fault_fifo_size;
+ attr.rx_fifo = vinst->fault_fifo;
+
+ /*
+ * Max creds is based on number of CRBs can fit in the FIFO.
+ * (fault_fifo_size/CRB_SIZE). If 8MB FIFO is used, max creds
+ * will be 0xffff since the receive creds field is 16bits wide.
+ */
+ attr.wcreds_max = vinst->fault_fifo_size / CRB_SIZE;
+ attr.lnotify_lpid = 0;
+ attr.lnotify_pid = mfspr(SPRN_PID);
+ attr.lnotify_tid = mfspr(SPRN_PID);
+
+ vinst->fault_win = vas_rx_win_open(vinst->vas_id, VAS_COP_TYPE_FAULT,
+ &attr);
+
+ if (IS_ERR(vinst->fault_win)) {
+ pr_err("VAS: Error %ld opening FaultWin\n",
+ PTR_ERR(vinst->fault_win));
+ kfree(vinst->fault_fifo);
+ return PTR_ERR(vinst->fault_win);
+ }
+
+ pr_devel("VAS: Created FaultWin %d, LPID/PID/TID [%d/%d/%d]\n",
+ vinst->fault_win->winid, attr.lnotify_lpid,
+ attr.lnotify_pid, attr.lnotify_tid);
+
+ return 0;
+}
diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 0c0d27d..1783fa9 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -827,9 +827,9 @@ void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr, enum vas_cop_type cop)
rxattr->fault_win = true;
rxattr->notify_disable = true;
rxattr->rx_wcred_mode = true;
- rxattr->tx_wcred_mode = true;
rxattr->rx_win_ord_mode = true;
- rxattr->tx_win_ord_mode = true;
+ rxattr->rej_no_credit = true;
+ rxattr->tc_mode = VAS_THRESH_DISABLED;
} else if (cop == VAS_COP_TYPE_FTW) {
rxattr->user_win = true;
rxattr->intr_disable = true;
diff --git a/arch/powerpc/platforms/powernv/vas.c b/arch/powerpc/platforms/powernv/vas.c
index 168ab68..557c8e4 100644
--- a/arch/powerpc/platforms/powernv/vas.c
+++ b/arch/powerpc/platforms/powernv/vas.c
@@ -24,6 +24,11 @@
static DEFINE_PER_CPU(int, cpu_vas_id);
+static int vas_irq_fault_window_setup(struct vas_instance *vinst)
+{
+ return vas_setup_fault_window(vinst);
+}
+
static int init_vas_instance(struct platform_device *pdev)
{
struct device_node *dn = pdev->dev.of_node;
@@ -104,6 +109,21 @@ static int init_vas_instance(struct platform_device *pdev)
list_add(&vinst->node, &vas_instances);
mutex_unlock(&vas_mutex);
+ /*
+ * IRQ and fault handling setup is needed only for user space
+ * send windows.
+ */
+ if (vinst->virq) {
+ rc = vas_irq_fault_window_setup(vinst);
+ /*
+ * Fault window is used only for user space send windows.
+ * So if vinst->virq is NULL, tx_win_open returns -ENODEV
+ * for user space.
+ */
+ if (rc)
+ vinst->virq = 0;
+ }
+
vas_instance_init_dbgdir(vinst);
dev_set_drvdata(&pdev->dev, vinst);
diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
index 598608b..6c4baf5 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -296,6 +296,17 @@ enum vas_notify_after_count {
};
/*
+ * NX can generate an interrupt for multiple faults and expects kernel
+ * to process all of them. So read all valid CRB entries until find the
+ * invalid one. So use pswid which is pasted by NX and ccw[0] (reserved
+ * bit in BE) to check valid CRB.
+ * Invalidate FIFO during allocation and process all entries from last
+ * successful read until finds invalid pswid and ccw[0] values.
+ */
+#define FIFO_INVALID_ENTRY 0xffffffff
+#define CCW0_INVALID 1
+
+/*
* One per instance of VAS. Each instance will have a separate set of
* receive windows, one per coprocessor type.
*
@@ -315,6 +326,10 @@ struct vas_instance {
u64 irq_port;
int virq;
+ int fault_fifo_size;
+ void *fault_fifo;
+ struct vas_window *fault_win; /* Fault window */
+
struct mutex mutex;
struct vas_window *rxwin[VAS_COP_TYPE_MAX];
struct vas_window *windows[VAS_WINDOWS_PER_CHIP];
@@ -408,6 +423,7 @@ struct vas_winctx {
extern void vas_instance_init_dbgdir(struct vas_instance *vinst);
extern void vas_window_init_dbgdir(struct vas_window *win);
extern void vas_window_free_dbgdir(struct vas_window *win);
+extern int vas_setup_fault_window(struct vas_instance *vinst);
static inline void vas_log_write(struct vas_window *win, char *name,
void *regptr, u64 val)
--
1.8.3.1
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