[PATCH 00/10] powerpc/pseries/vas: NXGZIP support with DLPAR

[PATCH 00/10] powerpc/pseries/vas: NXGZIP support with DLPAR

[Haren Myneni]

PowerPC provides HW compression with NX coprocessor. This feature
is available on both PowerNV and PowerVM and included in Linux.
Since each powerpc chip has one NX coprocessor, the VAS introduces
the concept of windows / credits to manage access to this hardware
resource. On powerVM, these limited resources should be available
across all LPARs. So the hypervisor assigns the specific credits
to each LPAR based on processor entitlement so that one LPAR does
not overload NX. The hypervisor can reject the window open request
to a partition if exceeds its credit limit (1 credit per window).

So the total number of target credits in a partition can be changed
if the core configuration is modified. The hypervisor expects the
partition to modify its window usage depends on new target
credits. For example, if the partition uses more credits than the
new target credits, it should close the excessive windows so that
the NX resource will be available to other partitions.

This patch series enables OS to support this dynamic credit
management with DLPAR core removal/add.

Core removal operation:
- Get new VAS capabilities from the hypervisor when the DLPAR
  notifier is received. This capabilities provides the new target
  credits based on new processor entitlement. In the case of QoS
  credit changes, the notification will be issued by updating
  the target_creds via sysfs.
- If the partition is already used more than the new target credits,
  the kernel selects windows, unmap the current paste address and
  close them in the hypervisor, It uses LIFO to identify these
  windows - last windows that are opened are the first ones to be
  closed.
- When the user space issue requests on these windows, NX generates
  page fault on the unmap paste address. The kernel handles the
  fault by returning the paste instruction failure if the window is
  not active (means unmap paste). Then up to the library / user
  space to fall back to SW compression or manage with the current
  windows.

Core add operation:
- The kernel can see increased target credits from the new VAS
  capabilities.
- Scans the window list for the closed windows in the hypervisor
  due to lost credit before and selects windows based on same LIFO.
- Make these corresponding windows active and create remap with
  the same VMA on the new paste address in the fault handler.
- Then the user space should expect paste successful later.

Patch 1: Define common names for sysfs target/used/avail_creds so
	 that same sysfs entries can be used even on PowerNV later.
Patch 2: Add VAS notifier for DLPAR core add / removal
Patch 3: Save LPID in the vas window struct  during initial window
	 open and use it when reopen later.
Patch 4: When credits are available, reopen windows that are closed
	 before with core removal.
Patch 5: Close windows in the hypervisor when the partition exceeds
	 its usage than the new target credits.
Patch 6: If the window is closed in the hypervisor before the user
	 space issue the initial mmap(), return -EACCES failure.
Patch 7: Add new mmap fault handler which handles the page fault
	 from NX on paste address.
Patch 8: Return the paste instruction failure if the window is not
	 active.
Patch 9 & 10: The user space determines the credit usage with sysfs
	 target/avail/used_creds interfaces. drmgr uses target_creds
	to notify OS for QoS credit changes.

Thanks to Nicholas Piggin and Aneesh Kumar for the valuable suggestions
on the NXGZIP design to support DLPAR operations.
  
Haren Myneni (10):
  powerpc/pseries/vas: Use common names in VAS capability structure
  powerpc/pseries/vas: Add notifier for DLPAR core removal/add
  powerpc/pseries/vas: Save partition PID in pseries_vas_window struct
  powerpc/pseries/vas: Reopen windows with DLPAR core add
  powerpc/pseries/vas: Close windows with DLPAR core removal
  powerpc/vas: Map paste address only if window is active
  powerpc/vas: Add paste address mmap fault handler
  powerpc/vas: Return paste instruction failure if window is not active
  powerpc/pseries/vas: sysfs interface to export capabilities
  powerpc/pseries/vas: Write 'target_creds' for QoS credits change

 arch/powerpc/include/asm/ppc-opcode.h      |   2 +
 arch/powerpc/include/asm/vas.h             |  16 ++
 arch/powerpc/platforms/book3s/vas-api.c    | 129 ++++++++-
 arch/powerpc/platforms/pseries/Makefile    |   2 +-
 arch/powerpc/platforms/pseries/vas-sysfs.c | 246 +++++++++++++++++
 arch/powerpc/platforms/pseries/vas.c       | 293 ++++++++++++++++++++-
 arch/powerpc/platforms/pseries/vas.h       |  16 +-
 7 files changed, 691 insertions(+), 13 deletions(-)
 create mode 100644 arch/powerpc/platforms/pseries/vas-sysfs.c

-- 
2.27.0

[PATCH 01/10] powerpc/pseries/vas: Use common names in VAS capability structure

[Haren Myneni]

target/used/avail_creds provides credits usage to user space via
sysfs and the same interface can be used on PowerNV in future.
Remove "lpar" from these names so that applicable on both PowerVM
and PowerNV.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas.c | 10 +++++-----
 arch/powerpc/platforms/pseries/vas.h |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index b043e3936d21..ecdd21f517c0 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -303,8 +303,8 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags,
 
 	cop_feat_caps = &caps->caps;
 
-	if (atomic_inc_return(&cop_feat_caps->used_lpar_creds) >
-			atomic_read(&cop_feat_caps->target_lpar_creds)) {
+	if (atomic_inc_return(&cop_feat_caps->used_creds) >
+			atomic_read(&cop_feat_caps->target_creds)) {
 		pr_err("Credits are not available to allocate window\n");
 		rc = -EINVAL;
 		goto out;
@@ -378,7 +378,7 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags,
 	free_irq_setup(txwin);
 	h_deallocate_vas_window(txwin->vas_win.winid);
 out:
-	atomic_dec(&cop_feat_caps->used_lpar_creds);
+	atomic_dec(&cop_feat_caps->used_creds);
 	kfree(txwin);
 	return ERR_PTR(rc);
 }
@@ -438,7 +438,7 @@ static int vas_deallocate_window(struct vas_window *vwin)
 	}
 
 	list_del(&win->win_list);
-	atomic_dec(&caps->used_lpar_creds);
+	atomic_dec(&caps->used_creds);
 	mutex_unlock(&vas_pseries_mutex);
 
 	put_vas_user_win_ref(&vwin->task_ref);
@@ -514,7 +514,7 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 	}
 	caps->max_lpar_creds = be16_to_cpu(hv_caps->max_lpar_creds);
 	caps->max_win_creds = be16_to_cpu(hv_caps->max_win_creds);
-	atomic_set(&caps->target_lpar_creds,
+	atomic_set(&caps->target_creds,
 		   be16_to_cpu(hv_caps->target_lpar_creds));
 	if (feat == VAS_GZIP_DEF_FEAT) {
 		caps->def_lpar_creds = be16_to_cpu(hv_caps->def_lpar_creds);
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 4ecb3fcabd10..fa7ce74f1e49 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -72,9 +72,9 @@ struct vas_cop_feat_caps {
 	};
 	/* Total LPAR available credits. Can be different from max LPAR */
 	/* credits due to DLPAR operation */
-	atomic_t	target_lpar_creds;
-	atomic_t	used_lpar_creds; /* Used credits so far */
-	u16		avail_lpar_creds; /* Remaining available credits */
+	atomic_t	target_creds;
+	atomic_t	used_creds;	/* Used credits so far */
+	u16		avail_creds;	/* Remaining available credits */
 };
 
 /*
-- 
2.27.0

[PATCH 02/10] powerpc/pseries/vas: Add notifier for DLPAR core removal/add

[Haren Myneni]

The hypervisor assigns credits for each LPAR based on number of
cores configured in that system. So expects to release credits
(means windows) when the core is removed. This patch adds notifier
for core removal/add so that the OS closes windows if the system
looses credits due to core removal and reopen windows when the
credits available later.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas.c | 34 ++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index ecdd21f517c0..04a6eee2301e 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -531,6 +531,36 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 	return 0;
 }
 
+/*
+ * Total number of default credits available (target_credits)
+ * in LPAR depends on number of cores configured. It varies based on
+ * whether processors are in shared mode or dedicated mode.
+ * Get the notifier when CPU configuration is changed with DLPAR
+ * operation so that get the new target_credits (vas default capabilities)
+ * and then update the existing windows usage if needed.
+ */
+static int pseries_vas_notifier(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct of_reconfig_data *rd = data;
+	struct device_node *dn = rd->dn;
+	const __be32 *intserv;
+	int len, rc = 0;
+
+	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
+	/*
+	 * Processor config is not changed
+	 */
+	if (!intserv)
+		return NOTIFY_OK;
+
+	return rc;
+}
+
+static struct notifier_block pseries_vas_nb = {
+	.notifier_call = pseries_vas_notifier,
+};
+
 static int __init pseries_vas_init(void)
 {
 	struct hv_vas_cop_feat_caps *hv_cop_caps;
@@ -584,6 +614,10 @@ static int __init pseries_vas_init(void)
 			goto out_cop;
 	}
 
+	/* Processors can be added/removed only on LPAR */
+	if (copypaste_feat && firmware_has_feature(FW_FEATURE_LPAR))
+		of_reconfig_notifier_register(&pseries_vas_nb);
+
 	pr_info("GZIP feature is available\n");
 
 out_cop:
-- 
2.27.0

[PATCH 03/10] powerpc/pseries/vas: Save LPID in pseries_vas_window struct

[Haren Myneni]

The kernel sets the VAS window with partition PID when is opened in
the hypervisor. During DLPAR operation, windows can be closed and
reopened in the hypervisor when the credit is available. So saves
this PID in pseries_vas_window struct when the window is opened
initially and reuse it later during DLPAR operation.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas.c | 6 +++---
 arch/powerpc/platforms/pseries/vas.h | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index 04a6eee2301e..6b35f67d5175 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -107,7 +107,6 @@ static int h_deallocate_vas_window(u64 winid)
 static int h_modify_vas_window(struct pseries_vas_window *win)
 {
 	long rc;
-	u32 lpid = mfspr(SPRN_PID);
 
 	/*
 	 * AMR value is not supported in Linux VAS implementation.
@@ -115,7 +114,7 @@ static int h_modify_vas_window(struct pseries_vas_window *win)
 	 */
 	do {
 		rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW,
-					win->vas_win.winid, lpid, 0,
+					win->vas_win.winid, win->lpid, 0,
 					VAS_MOD_WIN_FLAGS, 0);
 
 		rc = hcall_return_busy_check(rc);
@@ -125,7 +124,7 @@ static int h_modify_vas_window(struct pseries_vas_window *win)
 		return 0;
 
 	pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u lpid %u\n",
-			rc, win->vas_win.winid, lpid);
+			rc, win->vas_win.winid, win->lpid);
 	return -EIO;
 }
 
@@ -353,6 +352,7 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags,
 	if (rc)
 		goto out;
 
+	txwin->lpid = mfspr(SPRN_PID);
 	/*
 	 * Modify window and it is ready to use.
 	 */
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index fa7ce74f1e49..0538760d13be 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -115,6 +115,7 @@ struct pseries_vas_window {
 	u64 domain[6];		/* Associativity domain Ids */
 				/* this window is allocated */
 	u64 util;
+	u32 lpid;
 
 	/* List of windows opened which is used for LPM */
 	struct list_head win_list;
-- 
2.27.0

[PATCH 04/10] powerpc/pseries/vas: Reopen windows with DLPAR core add

[Haren Myneni]

VAS windows can be closed in the hypervisor due to lost credits
when the core is removed. If these credits are available later
for core add, reopen these windows and set them active. When the
kernel sees page fault on the paste address, it creates new 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 <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/vas.h          |  15 +++
 arch/powerpc/platforms/book3s/vas-api.c |   1 +
 arch/powerpc/platforms/pseries/vas.c    | 148 ++++++++++++++++++++++++
 arch/powerpc/platforms/pseries/vas.h    |   2 +
 4 files changed, 166 insertions(+)

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index 57573d9c1e09..43cea69d1af1 100644
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -29,6 +29,18 @@
 #define VAS_THRESH_FIFO_GT_QTR_FULL	2
 #define VAS_THRESH_FIFO_GT_EIGHTH_FULL	3
 
+/*
+ * VAS window status
+ */
+#define VAS_WIN_ACTIVE		0x0	/* Used in platform independent */
+					/* vas mmap() */
+#define VAS_WIN_CLOSED		0x1
+#define VAS_WIN_INACTIVE	0x2	/* Inactive due to HW failure */
+#define VAS_WIN_MOD_IN_PROCESS	0x3	/* Process of being modified, */
+					/* deallocated, or quiesced */
+#define VAS_WIN_NO_CRED_CLOSE	0x4	/* Linux specific status when */
+					/* window is closed due to lost */
+					/* credit */
 /*
  * Get/Set bit fields
  */
@@ -59,6 +71,8 @@ struct vas_user_win_ref {
 	struct pid *pid;	/* PID of owner */
 	struct pid *tgid;	/* Thread group ID of owner */
 	struct mm_struct *mm;	/* Linux process mm_struct */
+	struct mutex mmap_mutex;	/* protects paste address mmap() */
+					/* with DLPAR close/open windows */
 };
 
 /*
@@ -67,6 +81,7 @@ struct vas_user_win_ref {
 struct vas_window {
 	u32 winid;
 	u32 wcreds_max;	/* Window credits */
+	u32 status;
 	enum vas_cop_type cop;
 	struct vas_user_win_ref task_ref;
 	char *dbgname;
diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 4d82c92ddd52..2b0ced611f32 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -316,6 +316,7 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
 		return PTR_ERR(txwin);
 	}
 
+	mutex_init(&txwin->task_ref.mmap_mutex);
 	cp_inst->txwin = txwin;
 
 	return 0;
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index 6b35f67d5175..ace8ee7a99e6 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -493,6 +493,7 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 	memset(vcaps, 0, sizeof(*vcaps));
 	INIT_LIST_HEAD(&vcaps->list);
 
+	vcaps->feat = feat;
 	caps = &vcaps->caps;
 
 	rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, feat,
@@ -531,6 +532,149 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 	return 0;
 }
 
+/*
+ * 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;
+	int rc, mv_ents = 0;
+
+	/*
+	 * Nothing to do if there are no closed windows.
+	 */
+	if (!vcaps->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->close_wins > creds)
+		mv_ents = vcaps->close_wins - creds;
+
+	list_for_each_entry(win, &vcaps->list, win_list) {
+		if (!mv_ents)
+			break;
+
+		mv_ents--;
+	}
+
+	while (vcaps->close_wins && win) {
+		/*
+		 * Nothing to do on this window if it is active.
+		 */
+		if (win->vas_win.status != VAS_WIN_NO_CRED_CLOSE) {
+			win = list_next_entry(win, win_list);
+			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_ACTIVE;
+		win->win_type = caps->win_type;
+		mutex_unlock(&win->vas_win.task_ref.mmap_mutex);
+		atomic_inc(&caps->used_creds);
+		win = list_next_entry(win, win_list);
+		vcaps->close_wins--;
+	}
+
+	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;
+}
+
+/*
+ * Get new VAS capabilities when the core add/removal configuration
+ * changes. Reconfig window configurations based on the credits
+ * availability from this new capabilities.
+ */
+static int vas_reconfig_capabilties(u8 type)
+{
+	int lpar_creds, avail_creds;
+	struct hv_vas_cop_feat_caps *hv_caps;
+	struct vas_cop_feat_caps *caps;
+	struct vas_caps *vcaps;
+	int rc = 0;
+
+	if (type >= VAS_MAX_FEAT_TYPE) {
+		pr_err("Invalid credit type %d\n", type);
+		return -EINVAL;
+	}
+
+	vcaps = &vascaps[type];
+	caps = &vcaps->caps;
+
+	hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
+	if (!hv_caps)
+		return -ENOMEM;
+
+	mutex_lock(&vas_pseries_mutex);
+	rc = h_query_vas_capabilities(H_QUERY_VAS_CAPABILITIES, vcaps->feat,
+				      (u64)virt_to_phys(hv_caps));
+	if (rc)
+		goto out;
+
+	lpar_creds = be16_to_cpu(hv_caps->target_lpar_creds);
+
+	atomic_set(&caps->target_creds, lpar_creds);
+
+	/*
+	 * The total number of available credits are decreased due to
+	 * DLPAR core removal. Means some windows have to be closed.
+	 * Hold the vas_pseries_mutex before closing the required windows
+	 * so that the user space can not open new windows.
+	 */
+	if (atomic_read(&caps->used_creds) < lpar_creds) {
+		/*
+		 * If the existing used credits is less than the new
+		 * available credits, reopen windows if they are
+		 * closed due to the previous DLPAR (core removal).
+		 */
+		avail_creds = lpar_creds -
+				atomic_read(&caps->used_creds);
+		rc = reconfig_open_windows(vcaps, avail_creds);
+	}
+
+out:
+	mutex_unlock(&vas_pseries_mutex);
+	kfree(hv_caps);
+	return rc;
+}
+
 /*
  * Total number of default credits available (target_credits)
  * in LPAR depends on number of cores configured. It varies based on
@@ -554,6 +698,10 @@ static int pseries_vas_notifier(struct notifier_block *nb,
 	if (!intserv)
 		return NOTIFY_OK;
 
+	rc = vas_reconfig_capabilties(VAS_GZIP_DEF_FEAT_TYPE);
+	if (rc)
+		pr_err("Failed reconfig VAS capabilities with DLPAR\n");
+
 	return rc;
 }
 
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 0538760d13be..1fbb49a34d48 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -84,6 +84,8 @@ struct vas_cop_feat_caps {
 struct vas_caps {
 	struct vas_cop_feat_caps caps;
 	struct list_head list;	/* List of open windows */
+	int close_wins;		/* closed windows in the hypervisor for DLPAR */
+	u8 feat;		/* Feature type */
 };
 
 /*
-- 
2.27.0

[PATCH 05/10] powerpc/pseries/vas: Close windows with DLPAR core removal

[Haren Myneni]

The hypervisor reduces the available credits if the core is removed
from the LPAR. So there is possibility of using excessive credits
(windows) in the LPAR and the hypervisor expects the system to close
the excessive windows. Even though the user space can continue to use
these windows to send compression requests to NX, the hypervisor expects
the LPAR to reduce these windows usage so that NX load can be equally
distributed across all LPARs in the system.

When the DLPAR notifier is received, get the new VAS capabilities from
the hypervisor and close the excessive windows in the hypervisor. Also
the kernel unmaps the paste address so that the user space receives paste
failure until these windows are active with the later DLPAR (core add).

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/vas.h          |  1 +
 arch/powerpc/platforms/book3s/vas-api.c |  2 +
 arch/powerpc/platforms/pseries/vas.c    | 93 ++++++++++++++++++++++++-
 3 files changed, 94 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index 43cea69d1af1..72d1df038b4b 100644
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -73,6 +73,7 @@ struct vas_user_win_ref {
 	struct mm_struct *mm;	/* Linux process mm_struct */
 	struct mutex mmap_mutex;	/* protects paste address mmap() */
 					/* with DLPAR close/open windows */
+	struct vm_area_struct *vma;	/* Save VMA and used in DLPAR ops */
 };
 
 /*
diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 2b0ced611f32..a63fd48e34a7 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -399,6 +399,8 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
 	pr_devel("%s(): paste addr %llx at %lx, rc %d\n", __func__,
 			paste_addr, vma->vm_start, rc);
 
+	txwin->task_ref.vma = vma;
+
 	return rc;
 }
 
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index ace8ee7a99e6..ed458620f007 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -431,14 +431,27 @@ static int vas_deallocate_window(struct vas_window *vwin)
 
 	caps = &vascaps[win->win_type].caps;
 	mutex_lock(&vas_pseries_mutex);
+	/*
+	 * VAS window is already closed in the hypervisor when
+	 * lost the credit. So just remove the entry from
+	 * the list, remove task references and free vas_window
+	 * struct.
+	 */
+	if (win->vas_win.status == VAS_WIN_NO_CRED_CLOSE) {
+		vascaps[win->win_type].close_wins--;
+		goto out;
+	}
+
 	rc = deallocate_free_window(win);
 	if (rc) {
 		mutex_unlock(&vas_pseries_mutex);
 		return rc;
 	}
 
-	list_del(&win->win_list);
 	atomic_dec(&caps->used_creds);
+
+out:
+	list_del(&win->win_list);
 	mutex_unlock(&vas_pseries_mutex);
 
 	put_vas_user_win_ref(&vwin->task_ref);
@@ -617,6 +630,74 @@ static int reconfig_open_windows(struct vas_caps *vcaps, int creds)
 	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.
+ * So the kernel closes the excessive windows and unmap the paste address
+ * such that the user space receives paste instruction failure. Then up to
+ * the user space to fall back to SW compression and manage with the
+ * existing windows.
+ */
+static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds)
+{
+	struct vas_cop_feat_caps *caps =  &vcap->caps;
+	struct vm_area_struct *vma;
+	struct pseries_vas_window *win;
+	struct vas_user_win_ref *task_ref;
+	int rc = 0;
+
+	list_for_each_entry(win, &vcap->list, win_list) {
+		/*
+		 * This window is already closed due to lost credit
+		 * before. Go for next window.
+		 */
+		if (win->vas_win.status == VAS_WIN_NO_CRED_CLOSE)
+			continue;
+
+		task_ref = &win->vas_win.task_ref;
+		mutex_lock(&task_ref->mmap_mutex);
+		vma = task_ref->vma;
+		/*
+		 * Number of available credits are reduced, So select
+		 * and close windows.
+		 */
+		win->vas_win.status = VAS_WIN_NO_CRED_CLOSE;
+
+		mmap_write_lock(task_ref->mm);
+		/*
+		 * vma is set in the original mapping. But this mapping
+		 * is done with mmap() after the window is opened with ioctl.
+		 * so we may not see the original mapping if the core remove
+		 * is done before the original mmap() and after the ioctl.
+		 */
+		if (vma)
+			zap_page_range(vma, vma->vm_start,
+					vma->vm_end - vma->vm_start);
+
+		mmap_write_unlock(task_ref->mm);
+		mutex_unlock(&task_ref->mmap_mutex);
+		/*
+		 * Close VAS window in the hypervisor, but do not
+		 * free vas_window struct since it may be reused
+		 * when the credit is available later (DLPAR with
+		 * adding cores). This struct will be used
+		 * later when the process issued with close(FD).
+		 */
+		rc = deallocate_free_window(win);
+		if (rc)
+			return rc;
+
+		atomic_dec(&caps->used_creds);
+		vcap->close_wins++;
+
+		if (!--excess_creds)
+			break;
+	}
+
+	return 0;
+}
+
 /*
  * Get new VAS capabilities when the core add/removal configuration
  * changes. Reconfig window configurations based on the credits
@@ -624,7 +705,7 @@ static int reconfig_open_windows(struct vas_caps *vcaps, int creds)
  */
 static int vas_reconfig_capabilties(u8 type)
 {
-	int lpar_creds, avail_creds;
+	int lpar_creds, avail_creds, excess_creds;
 	struct hv_vas_cop_feat_caps *hv_caps;
 	struct vas_cop_feat_caps *caps;
 	struct vas_caps *vcaps;
@@ -667,6 +748,14 @@ static int vas_reconfig_capabilties(u8 type)
 		avail_creds = lpar_creds -
 				atomic_read(&caps->used_creds);
 		rc = reconfig_open_windows(vcaps, avail_creds);
+	} else if (atomic_read(&caps->used_creds) > lpar_creds) {
+		/*
+		 * # open windows is more than new LPAR available
+		 * credits. So close the excessive windows.
+		 */
+		excess_creds = atomic_read(&caps->used_creds) -
+					lpar_creds;
+		rc = reconfig_close_windows(vcaps, excess_creds);
 	}
 
 out:
-- 
2.27.0

[PATCH 06/10] powerpc/vas: Map paste address only if window is active

[Haren Myneni]

The paste address mapping is done with mmap() after the window is
opened with ioctl. But the window can be closed due to lost credit
due to core removal before mmap(). So if the window is not active,
return mmap() failure with -EACCES and expects the user space reissue
mmap() when the window is active or open new window when the credit
is available.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/book3s/vas-api.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/book3s/vas-api.c
b/arch/powerpc/platforms/book3s/vas-api.c
index a63fd48e34a7..2d06bd1b1935 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -379,10 +379,27 @@ static int coproc_mmap(struct file *fp, struct
vm_area_struct *vma)
 		return -EACCES;
 	}
 
+	/*
+	 * The initial mapping is done after the window is opened
+	 * with ioctl. But this window might have been closed
+	 * due to lost credit (core removal on PowerVM) before mmap().
+	 * So if the window is not active, return mmap() failure
+	 * with -EACCES and expects the user space reconfigure (mmap)
+	 * window when it is active again or open new window when
+	 * the credit is available.
+	 */
+	mutex_lock(&txwin->task_ref.mmap_mutex);
+	if (txwin->status != VAS_WIN_ACTIVE) {
+		pr_err("%s(): Window is not active\n", __func__);
+		rc = -EACCES;
+		goto out;
+	}
+
 	paste_addr = cp_inst->coproc->vops->paste_addr(txwin);
 	if (!paste_addr) {
 		pr_err("%s(): Window paste address failed\n",
__func__);
-		return -EINVAL;
+		rc = -EINVAL;
+		goto out;
 	}
 
 	pfn = paste_addr >> PAGE_SHIFT;
@@ -401,6 +418,8 @@ static int coproc_mmap(struct file *fp, struct
vm_area_struct *vma)
 
 	txwin->task_ref.vma = vma;
 
+out:
+	mutex_unlock(&txwin->task_ref.mmap_mutex);
 	return rc;
 }
 
-- 
2.27.0

[PATCH 07/10] powerpc/vas: Add paste address mmap fault handler

[Haren Myneni]

The user space opens VAS windows and issues NX requests by pasting
CRB on the corresponding paste address mmap. When the system looses
credits due to core removal, the kernel has to close the window in
the hypervisor and make the window inactive by unmapping this paste
address. Also the OS has to handle NX request page faults if the user
space issue NX requests.

This handler remap the new paste address with the same VMA when the
window is active again (due to core add with DLPAR). Otherwise
returns paste failure.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/book3s/vas-api.c | 60 +++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 2d06bd1b1935..5ceba75c13eb 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -351,6 +351,65 @@ static int coproc_release(struct inode *inode, struct file *fp)
 	return 0;
 }
 
+/*
+ * This fault handler is invoked when the VAS/NX generates page fault on
+ * the paste address. Happens if the kernel closes window in hypervisor
+ * (on PowerVM) due to lost credit or the paste address is not mapped.
+ */
+static vm_fault_t vas_mmap_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct file *fp = vma->vm_file;
+	struct coproc_instance *cp_inst = fp->private_data;
+	struct vas_window *txwin;
+	u64 paste_addr;
+	int ret;
+
+	/*
+	 * window is not opened. Shouldn't expect this error.
+	 */
+	if (!cp_inst || !cp_inst->txwin) {
+		pr_err("%s(): No send window open?\n", __func__);
+		return VM_FAULT_SIGBUS;
+	}
+
+	txwin = cp_inst->txwin;
+	/*
+	 * Fault is coming due to missing from the original mmap.
+	 * Can happen only when the window is closed due to lost
+	 * credit before mmap() or the user space issued NX request
+	 * without mapping.
+	 */
+	if (txwin->task_ref.vma != vmf->vma) {
+		pr_err("%s(): No previous mapping with paste address\n",
+			__func__);
+		return VM_FAULT_SIGBUS;
+	}
+
+	mutex_lock(&txwin->task_ref.mmap_mutex);
+	/*
+	 * The window may be inactive due to lost credit (Ex: core
+	 * removal with DLPAR). When the window is active again when
+	 * the credit is available, remap with the new paste address.
+	 */
+	if (txwin->status == VAS_WIN_ACTIVE) {
+		paste_addr = cp_inst->coproc->vops->paste_addr(txwin);
+		if (paste_addr) {
+			ret = vmf_insert_pfn(vma, vma->vm_start,
+					(paste_addr >> PAGE_SHIFT));
+			mutex_unlock(&txwin->task_ref.mmap_mutex);
+			return ret;
+		}
+	}
+	mutex_unlock(&txwin->task_ref.mmap_mutex);
+
+	return VM_FAULT_SIGBUS;
+
+}
+static const struct vm_operations_struct vas_vm_ops = {
+	.fault = vas_mmap_fault,
+};
+
 static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
 {
 	struct coproc_instance *cp_inst = fp->private_data;
@@ -417,6 +476,7 @@ static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
 			paste_addr, vma->vm_start, rc);
 
 	txwin->task_ref.vma = vma;
+	vma->vm_ops = &vas_vm_ops;
 
 out:
 	mutex_unlock(&txwin->task_ref.mmap_mutex);
-- 
2.27.0

[PATCH 08/10] powerpc/vas: Return paste instruction failure if no active window

[Haren Myneni]

The VAS window may not be active if the system looses credits and
the NX generates page fault when it receives request on unmap
paste address.

The kernel handles the fault by remap new paste address if the
window is active again, Otherwise return the paste instruction
failure if the executed instruction that caused the fault was
a paste.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/include/asm/ppc-opcode.h   |  2 ++
 arch/powerpc/platforms/book3s/vas-api.c | 47 ++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index baea657bc868..30bb3c0e07f9 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -261,6 +261,8 @@
 #define PPC_INST_MFSPR_PVR		0x7c1f42a6
 #define PPC_INST_MFSPR_PVR_MASK		0xfc1ffffe
 #define PPC_INST_MTMSRD			0x7c000164
+#define PPC_INST_PASTE			0x7c20070d
+#define PPC_INST_PASTE_MASK		0xfc2007ff
 #define PPC_INST_POPCNTB		0x7c0000f4
 #define PPC_INST_POPCNTB_MASK		0xfc0007fe
 #define PPC_INST_RFEBB			0x4c000124
diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c
index 5ceba75c13eb..2ffd34bc4032 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -351,6 +351,41 @@ static int coproc_release(struct inode *inode, struct file *fp)
 	return 0;
 }
 
+/*
+ * If the executed instruction that caused the fault was a paste, then
+ * clear regs CR0[EQ], advance NIP, and return 0. Else return error code.
+ */
+static int do_fail_paste(void)
+{
+	struct pt_regs *regs = current->thread.regs;
+	u32 instword;
+
+	if (WARN_ON_ONCE(!regs))
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(!user_mode(regs)))
+		return -EINVAL;
+
+	/*
+	 * If we couldn't translate the instruction, the driver should
+	 * return success without handling the fault, it will be retried
+	 * or the instruction fetch will fault.
+	 */
+	if (get_user(instword, (u32 __user *)(regs->nip)))
+		return -EAGAIN;
+
+	/*
+	 * Not a paste instruction, driver may fail the fault.
+	 */
+	if ((instword & PPC_INST_PASTE_MASK) != PPC_INST_PASTE)
+		return -ENOENT;
+
+	regs->ccr &= ~0xe0000000;	/* Clear CR0[0-2] to fail paste */
+	regs_add_return_ip(regs, 4);	/* Skip the paste */
+
+	return 0;
+}
+
 /*
  * This fault handler is invoked when the VAS/NX generates page fault on
  * the paste address. Happens if the kernel closes window in hypervisor
@@ -403,9 +438,19 @@ static vm_fault_t vas_mmap_fault(struct vm_fault *vmf)
 	}
 	mutex_unlock(&txwin->task_ref.mmap_mutex);
 
-	return VM_FAULT_SIGBUS;
+	/*
+	 * Received this fault due to closing the actual window.
+	 * It can happen during migration or lost credits.
+	 * Since no mapping, return the paste instruction failure
+	 * to the user space.
+	 */
+	ret = do_fail_paste();
+	if (!ret)
+		return VM_FAULT_NOPAGE;
 
+	return VM_FAULT_SIGBUS;
 }
+
 static const struct vm_operations_struct vas_vm_ops = {
 	.fault = vas_mmap_fault,
 };
-- 
2.27.0

[PATCH 09/10] powerpc/pseries/vas: sysfs interface to export capabilities

[Haren Myneni]

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/def_caps: (default GZIP capabilities)
	avail_creds /* Available credits to use */
	target_creds /* Total credits available. Can be
			 /* changed with DLPAR operation */
	used_creds  /* Used credits */

/sys/devices/vas/vas0/gzip/qos_caps (QoS GZIP capabilities)
	avail_creds
	target_creds
	used_creds

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/Makefile    |   2 +-
 arch/powerpc/platforms/pseries/vas-sysfs.c | 214 +++++++++++++++++++++
 arch/powerpc/platforms/pseries/vas.c       |   6 +
 arch/powerpc/platforms/pseries/vas.h       |   6 +
 4 files changed, 227 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/pseries/vas-sysfs.c

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 41d8aee98da4..349f42c31b65 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -30,6 +30,6 @@ obj-$(CONFIG_PPC_SVM)		+= svm.o
 obj-$(CONFIG_FA_DUMP)		+= rtas-fadump.o
 
 obj-$(CONFIG_SUSPEND)		+= suspend.o
-obj-$(CONFIG_PPC_VAS)		+= vas.o
+obj-$(CONFIG_PPC_VAS)		+= vas.o vas-sysfs.o
 
 obj-$(CONFIG_ARCH_HAS_CC_PLATFORM)	+= cc_platform.o
diff --git a/arch/powerpc/platforms/pseries/vas-sysfs.c b/arch/powerpc/platforms/pseries/vas-sysfs.c
new file mode 100644
index 000000000000..625082bebcb2
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/vas-sysfs.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2016-17 IBM Corp.
+ */
+
+#define pr_fmt(fmt) "vas: " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include "vas.h"
+
+#ifdef CONFIG_SYSFS
+static struct kobject *pseries_vas_kobj;
+static struct kobject *gzip_caps_kobj;
+
+struct vas_caps_entry {
+	struct kobject kobj;
+	struct vas_cop_feat_caps *caps;
+};
+
+#define to_caps_entry(entry) container_of(entry, struct vas_caps_entry, kobj)
+
+static ssize_t avail_creds_show(struct vas_cop_feat_caps *caps, char *buf)
+{
+	int avail_creds = atomic_read(&caps->target_creds) -
+			atomic_read(&caps->used_creds);
+	return sprintf(buf, "%d\n", avail_creds);
+}
+
+#define sysfs_capbs_entry_read(_name)					\
+static ssize_t _name##_show(struct vas_cop_feat_caps *caps, char *buf) 	\
+{									\
+	return sprintf(buf, "%d\n", atomic_read(&caps->_name));	\
+}
+
+struct vas_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct vas_cop_feat_caps *, char *);
+	ssize_t (*store)(struct vas_cop_feat_caps *, const char *, size_t);
+};
+
+#define VAS_ATTR_RO(_name)	\
+	sysfs_capbs_entry_read(_name);		\
+	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name,	\
+				0444, _name##_show, NULL);
+
+VAS_ATTR_RO(target_creds);
+VAS_ATTR_RO(used_creds);
+
+static struct vas_sysfs_entry avail_creds_attribute =
+	__ATTR(avail_creds, 0444, avail_creds_show, NULL);
+
+static struct attribute *vas_capab_attrs[] = {
+	&target_creds_attribute.attr,
+	&used_creds_attribute.attr,
+	&avail_creds_attribute.attr,
+	NULL,
+};
+
+static ssize_t vas_type_show(struct kobject *kobj, struct attribute *attr,
+			     char *buf)
+{
+	struct vas_caps_entry *centry;
+	struct vas_cop_feat_caps *caps;
+	struct vas_sysfs_entry *entry;
+
+	centry = to_caps_entry(kobj);
+	caps = centry->caps;
+	entry = container_of(attr, struct vas_sysfs_entry, attr);
+
+	if (!entry->show)
+		return -EIO;
+
+	return entry->show(caps, buf);
+}
+
+static ssize_t vas_type_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct vas_caps_entry *centry;
+	struct vas_cop_feat_caps *caps;
+	struct vas_sysfs_entry *entry;
+
+	centry = to_caps_entry(kobj);
+	caps = centry->caps;
+	entry = container_of(attr, struct vas_sysfs_entry, attr);
+	if (!entry->store)
+		return -EIO;
+
+	return entry->store(caps, buf, count);
+}
+
+static void vas_type_release(struct kobject *kobj)
+{
+	struct vas_caps_entry *centry = to_caps_entry(kobj);
+	kfree(centry);
+}
+
+static const struct sysfs_ops vas_sysfs_ops = {
+	.show	=	vas_type_show,
+	.store	=	vas_type_store,
+};
+
+static struct kobj_type vas_attr_type = {
+		.release	=	vas_type_release,
+		.sysfs_ops      =       &vas_sysfs_ops,
+		.default_attrs  =       vas_capab_attrs,
+};
+
+static char *vas_caps_kobj_name(struct vas_cop_feat_caps *caps,
+				struct kobject **kobj)
+{
+	if (caps->descriptor == VAS_GZIP_QOS_CAPABILITIES) {
+		*kobj = gzip_caps_kobj;
+		return "qos_caps";
+	} else if (caps->descriptor == VAS_GZIP_DEFAULT_CAPABILITIES) {
+		*kobj = gzip_caps_kobj;
+		return "def_caps";
+	} else
+		return "Unknown";
+}
+
+/*
+ * Add feature specific capability dir entry.
+ * Ex: VDefGzip or VQosGzip
+ */
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
+{
+	struct vas_caps_entry *centry;
+	struct kobject *kobj = NULL;
+	int ret = 0;
+	char *name;
+
+	centry = kzalloc(sizeof(*centry), GFP_KERNEL);
+	if (!centry)
+		return -ENOMEM;
+
+	kobject_init(&centry->kobj, &vas_attr_type);
+	centry->caps = caps;
+	name  = vas_caps_kobj_name(caps, &kobj);
+
+	if (kobj) {
+		ret = kobject_add(&centry->kobj, kobj, "%s", name);
+
+		if (ret) {
+			pr_err("VAS: sysfs kobject add / event failed %d\n",
+					ret);
+			kobject_put(&centry->kobj);
+		}
+	}
+
+	return ret;
+}
+
+static struct miscdevice vas_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "vas",
+};
+
+/*
+ * Add VAS and VasCaps (overall capabilities) dir entries.
+ */
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
+{
+	int ret;
+
+	ret = misc_register(&vas_miscdev);
+	if (ret < 0) {
+		pr_err("%s: register vas misc device failed\n", __func__);
+		return ret;
+	}
+
+	/*
+	 * The hypervisor does not expose multiple VAS instances, but can
+	 * see multiple VAS instances on PowerNV. So create 'vas0' directory
+	 * on PowerVM.
+	 */
+	pseries_vas_kobj = kobject_create_and_add("vas0",
+					&vas_miscdev.this_device->kobj);
+	if (!pseries_vas_kobj) {
+		pr_err("Failed to create VAS sysfs entry\n");
+		return -ENOMEM;
+	}
+
+	if ((vas_caps->feat_type & VAS_GZIP_QOS_FEAT_BIT) ||
+		(vas_caps->feat_type & VAS_GZIP_DEF_FEAT_BIT)) {
+		gzip_caps_kobj = kobject_create_and_add("gzip",
+						       pseries_vas_kobj);
+		if (!gzip_caps_kobj) {
+			pr_err("Failed to create VAS GZIP capability entry\n");
+			kobject_put(pseries_vas_kobj);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+#else
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
+{
+	return 0;
+}
+
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
+{
+	return 0;
+}
+#endif
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index ed458620f007..c769c8534b3a 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -540,6 +540,10 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
 		}
 	}
 
+	rc = sysfs_add_vas_caps(caps);
+	if (rc)
+		return rc;
+
 	copypaste_feat = true;
 
 	return 0;
@@ -826,6 +830,8 @@ static int __init pseries_vas_init(void)
 	caps_all.descriptor = be64_to_cpu(hv_caps->descriptor);
 	caps_all.feat_type = be64_to_cpu(hv_caps->feat_type);
 
+	sysfs_pseries_vas_init(&caps_all);
+
 	hv_cop_caps = kmalloc(sizeof(*hv_cop_caps), GFP_KERNEL);
 	if (!hv_cop_caps) {
 		rc = -ENOMEM;
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 1fbb49a34d48..15bcadf8872a 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -30,6 +30,9 @@
 #define VAS_COPY_PASTE_USER_MODE	0x00000001
 #define VAS_COP_OP_USER_MODE		0x00000010
 
+#define VAS_GZIP_QOS_CAPABILITIES	0x56516F73477A6970
+#define VAS_GZIP_DEFAULT_CAPABILITIES	0x56446566477A6970
+
 /*
  * Co-processor feature - GZIP QoS windows or GZIP default windows
  */
@@ -125,4 +128,7 @@ struct pseries_vas_window {
 	char *name;
 	int fault_virq;
 };
+
+int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps);
+int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps);
 #endif /* _VAS_H */
-- 
2.27.0

[PATCH 10/10] powerpc/pseries/vas: Write 'target_creds' for QoS credits change

[Haren Myneni]

PowerVM support two types of credits - Default (uses normal priority
FIFO) and Qality of service (QoS uses high priproty FIFO). The user
decides the number of QoS credits and sets this value with HMC
interface. With the core add/removal, this value can be changed in HMC
which invokes drmgr to communicate to the kernel.

This patch adds an interface so that drmgr command can write the new
target QoS credits in sysfs. But the kernel gets the new QoS
capabilities from the hypervisor whenever target_creds is updated
to make sure sync with the values in the hypervisor.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/vas-sysfs.c | 34 +++++++++++++++++++++-
 arch/powerpc/platforms/pseries/vas.c       |  2 +-
 arch/powerpc/platforms/pseries/vas.h       |  1 +
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/vas-sysfs.c b/arch/powerpc/platforms/pseries/vas-sysfs.c
index 625082bebcb2..5bae2269d194 100644
--- a/arch/powerpc/platforms/pseries/vas-sysfs.c
+++ b/arch/powerpc/platforms/pseries/vas-sysfs.c
@@ -32,6 +32,34 @@ static ssize_t avail_creds_show(struct vas_cop_feat_caps *caps, char *buf)
 	return sprintf(buf, "%d\n", avail_creds);
 }
 
+/*
+ * This function is used to get the notification from the drmgr when
+ * QoS credits are changed as part of DLPAR core add/removal. Though
+ * receiving the total QoS credits here, get the official QoS
+ * capabilities from the hypervisor.
+ */
+static ssize_t target_creds_store(struct vas_cop_feat_caps *caps,
+				       const char *buf, size_t count)
+{
+	int err;
+	u16 creds;
+
+	/*
+	 * Nothing to do for default credit type.
+	 */
+	if (caps->win_type == VAS_GZIP_DEF_FEAT_TYPE)
+		return -EOPNOTSUPP;
+
+	err = kstrtou16(buf, 0, &creds);
+	if (!err)
+		err = vas_reconfig_capabilties(caps->win_type);
+
+	if (err)
+		return -EINVAL;
+
+	return count;
+}
+
 #define sysfs_capbs_entry_read(_name)					\
 static ssize_t _name##_show(struct vas_cop_feat_caps *caps, char *buf) 	\
 {									\
@@ -48,8 +76,12 @@ struct vas_sysfs_entry {
 	sysfs_capbs_entry_read(_name);		\
 	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name,	\
 				0444, _name##_show, NULL);
+#define VAS_ATTR(_name)							\
+	sysfs_capbs_entry_read(_name);					\
+	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name, \
+				0644, _name##_show, _name##_store)
 
-VAS_ATTR_RO(target_creds);
+VAS_ATTR(target_creds);
 VAS_ATTR_RO(used_creds);
 
 static struct vas_sysfs_entry avail_creds_attribute =
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index c769c8534b3a..d271fa71bded 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -707,7 +707,7 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds)
  * changes. Reconfig window configurations based on the credits
  * availability from this new capabilities.
  */
-static int vas_reconfig_capabilties(u8 type)
+int vas_reconfig_capabilties(u8 type)
 {
 	int lpar_creds, avail_creds, excess_creds;
 	struct hv_vas_cop_feat_caps *hv_caps;
diff --git a/arch/powerpc/platforms/pseries/vas.h b/arch/powerpc/platforms/pseries/vas.h
index 15bcadf8872a..e369db35f0fd 100644
--- a/arch/powerpc/platforms/pseries/vas.h
+++ b/arch/powerpc/platforms/pseries/vas.h
@@ -130,5 +130,6 @@ struct pseries_vas_window {
 };
 
 int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps);
+int vas_reconfig_capabilties(u8 type);
 int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps);
 #endif /* _VAS_H */
-- 
2.27.0