Merge branch 'pci/vc' into next

* pci/vc:
  PCI: Rename PCI_VC_PORT_REG1/2 to PCI_VC_PORT_CAP1/2
  PCI: Add Virtual Channel to save/restore support
  PCI: Add support for save/restore of extended capabilities
  PCI: Add pci_wait_for_pending() (refactor pci_wait_for_pending_transaction())

drivers/pci/Makefile

@@ -4,7 +4,7 @@
 
 obj-y		+= access.o bus.o probe.o host-bridge.o remove.o pci.o \
 			pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \
-			irq.o vpd.o setup-bus.o
+			irq.o vpd.o setup-bus.o vc.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_SYSFS) += slot.o
 

drivers/pci/pci.c

@@ -430,6 +430,32 @@ pci_find_parent_resource(const struct pci_dev *dev, struct resource *res)
 	return best;
 }
 
+/**
+ * pci_wait_for_pending - wait for @mask bit(s) to clear in status word @pos
+ * @dev: the PCI device to operate on
+ * @pos: config space offset of status word
+ * @mask: mask of bit(s) to care about in status word
+ *
+ * Return 1 when mask bit(s) in status word clear, 0 otherwise.
+ */
+int pci_wait_for_pending(struct pci_dev *dev, int pos, u16 mask)
+{
+	int i;
+
+	/* Wait for Transaction Pending bit clean */
+	for (i = 0; i < 4; i++) {
+		u16 status;
+		if (i)
+			msleep((1 << (i - 1)) * 100);
+
+		pci_read_config_word(dev, pos, &status);
+		if (!(status & mask))
+			return 1;
+	}
+
+	return 0;
+}
+
 /**
  * pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
  * @dev: PCI device to have its BARs restored
@@ -835,18 +861,28 @@ EXPORT_SYMBOL(pci_choose_state);
 #define PCI_EXP_SAVE_REGS	7
 
 
-static struct pci_cap_saved_state *pci_find_saved_cap(
-	struct pci_dev *pci_dev, char cap)
+static struct pci_cap_saved_state *_pci_find_saved_cap(struct pci_dev *pci_dev,
+						       u16 cap, bool extended)
 {
 	struct pci_cap_saved_state *tmp;
 
 	hlist_for_each_entry(tmp, &pci_dev->saved_cap_space, next) {
-		if (tmp->cap.cap_nr == cap)
+		if (tmp->cap.cap_extended == extended && tmp->cap.cap_nr == cap)
 			return tmp;
 	}
 	return NULL;
 }
 
+struct pci_cap_saved_state *pci_find_saved_cap(struct pci_dev *dev, char cap)
+{
+	return _pci_find_saved_cap(dev, cap, false);
+}
+
+struct pci_cap_saved_state *pci_find_saved_ext_cap(struct pci_dev *dev, u16 cap)
+{
+	return _pci_find_saved_cap(dev, cap, true);
+}
+
 static int pci_save_pcie_state(struct pci_dev *dev)
 {
 	int i = 0;
@@ -948,6 +984,8 @@ pci_save_state(struct pci_dev *dev)
 		return i;
 	if ((i = pci_save_pcix_state(dev)) != 0)
 		return i;
+	if ((i = pci_save_vc_state(dev)) != 0)
+		return i;
 	return 0;
 }
 
@@ -1010,6 +1048,7 @@ void pci_restore_state(struct pci_dev *dev)
 	/* PCI Express register must be restored first */
 	pci_restore_pcie_state(dev);
 	pci_restore_ats_state(dev);
+	pci_restore_vc_state(dev);
 
 	pci_restore_config_space(dev);
 
@@ -1087,7 +1126,7 @@ int pci_load_saved_state(struct pci_dev *dev, struct pci_saved_state *state)
 	while (cap->size) {
 		struct pci_cap_saved_state *tmp;
 
-		tmp = pci_find_saved_cap(dev, cap->cap_nr);
+		tmp = _pci_find_saved_cap(dev, cap->cap_nr, cap->cap_extended);
 		if (!tmp || tmp->cap.size != cap->size)
 			return -EINVAL;
 
@@ -2021,18 +2060,24 @@ static void pci_add_saved_cap(struct pci_dev *pci_dev,
 }
 
 /**
- * pci_add_cap_save_buffer - allocate buffer for saving given capability registers
+ * _pci_add_cap_save_buffer - allocate buffer for saving given
+ *                            capability registers
  * @dev: the PCI device
  * @cap: the capability to allocate the buffer for
+ * @extended: Standard or Extended capability ID
  * @size: requested size of the buffer
  */
-static int pci_add_cap_save_buffer(
-	struct pci_dev *dev, char cap, unsigned int size)
+static int _pci_add_cap_save_buffer(struct pci_dev *dev, u16 cap,
+				    bool extended, unsigned int size)
 {
 	int pos;
 	struct pci_cap_saved_state *save_state;
 
-	pos = pci_find_capability(dev, cap);
+	if (extended)
+		pos = pci_find_ext_capability(dev, cap);
+	else
+		pos = pci_find_capability(dev, cap);
+
 	if (pos <= 0)
 		return 0;
 
@@ -2041,12 +2086,23 @@ static int pci_add_cap_save_buffer(
 		return -ENOMEM;
 
 	save_state->cap.cap_nr = cap;
+	save_state->cap.cap_extended = extended;
 	save_state->cap.size = size;
 	pci_add_saved_cap(dev, save_state);
 
 	return 0;
 }
 
+int pci_add_cap_save_buffer(struct pci_dev *dev, char cap, unsigned int size)
+{
+	return _pci_add_cap_save_buffer(dev, cap, false, size);
+}
+
+int pci_add_ext_cap_save_buffer(struct pci_dev *dev, u16 cap, unsigned int size)
+{
+	return _pci_add_cap_save_buffer(dev, cap, true, size);
+}
+
 /**
  * pci_allocate_cap_save_buffers - allocate buffers for saving capabilities
  * @dev: the PCI device
@@ -2065,6 +2121,8 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev)
 	if (error)
 		dev_err(&dev->dev,
 			"unable to preallocate PCI-X save buffer\n");
+
+	pci_allocate_vc_save_buffers(dev);
 }
 
 void pci_free_cap_save_buffers(struct pci_dev *dev)
@@ -3204,20 +3262,10 @@ EXPORT_SYMBOL(pci_set_dma_seg_boundary);
  */
 int pci_wait_for_pending_transaction(struct pci_dev *dev)
 {
-	int i;
-	u16 status;
-
-	/* Wait for Transaction Pending bit clean */
-	for (i = 0; i < 4; i++) {
-		if (i)
-			msleep((1 << (i - 1)) * 100);
-
-		pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &status);
-		if (!(status & PCI_EXP_DEVSTA_TRPND))
-			return 1;
-	}
+	if (!pci_is_pcie(dev))
+		return 1;
 
-	return 0;
+	return pci_wait_for_pending(dev, PCI_EXP_DEVSTA, PCI_EXP_DEVSTA_TRPND);
 }
 EXPORT_SYMBOL(pci_wait_for_pending_transaction);
 
@@ -3244,10 +3292,8 @@ static int pcie_flr(struct pci_dev *dev, int probe)
 
 static int pci_af_flr(struct pci_dev *dev, int probe)
 {
-	int i;
 	int pos;
 	u8 cap;
-	u8 status;
 
 	pos = pci_find_capability(dev, PCI_CAP_ID_AF);
 	if (!pos)
@@ -3261,14 +3307,8 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
 		return 0;
 
 	/* Wait for Transaction Pending bit clean */
-	for (i = 0; i < 4; i++) {
-		if (i)
-			msleep((1 << (i - 1)) * 100);
-
-		pci_read_config_byte(dev, pos + PCI_AF_STATUS, &status);
-		if (!(status & PCI_AF_STATUS_TP))
-			goto clear;
-	}
+	if (pci_wait_for_pending(dev, PCI_AF_STATUS, PCI_AF_STATUS_TP))
+		goto clear;
 
 	dev_err(&dev->dev, "transaction is not cleared; "
 			"proceeding with reset anyway\n");

drivers/pci/vc.c

+/*
+ * PCI Virtual Channel support
+ *
+ * Copyright (C) 2013 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
+#include <linux/types.h>
+
+/**
+ * pci_vc_save_restore_dwords - Save or restore a series of dwords
+ * @dev: device
+ * @pos: starting config space position
+ * @buf: buffer to save to or restore from
+ * @dwords: number of dwords to save/restore
+ * @save: whether to save or restore
+ */
+static void pci_vc_save_restore_dwords(struct pci_dev *dev, int pos,
+				       u32 *buf, int dwords, bool save)
+{
+	int i;
+
+	for (i = 0; i < dwords; i++, buf++) {
+		if (save)
+			pci_read_config_dword(dev, pos + (i * 4), buf);
+		else
+			pci_write_config_dword(dev, pos + (i * 4), *buf);
+	}
+}
+
+/**
+ * pci_vc_load_arb_table - load and wait for VC arbitration table
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ *
+ * Set Load VC Arbitration Table bit requesting hardware to apply the VC
+ * Arbitration Table (previously loaded).  When the VC Arbitration Table
+ * Status clears, hardware has latched the table into VC arbitration logic.
+ */
+static void pci_vc_load_arb_table(struct pci_dev *dev, int pos)
+{
+	u16 ctrl;
+
+	pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL, &ctrl);
+	pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL,
+			      ctrl | PCI_VC_PORT_CTRL_LOAD_TABLE);
+	if (pci_wait_for_pending(dev, pos + PCI_VC_PORT_STATUS,
+				 PCI_VC_PORT_STATUS_TABLE))
+		return;
+
+	dev_err(&dev->dev, "VC arbitration table failed to load\n");
+}
+
+/**
+ * pci_vc_load_port_arb_table - Load and wait for VC port arbitration table
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @res: VC resource number, ie. VCn (0-7)
+ *
+ * Set Load Port Arbitration Table bit requesting hardware to apply the Port
+ * Arbitration Table (previously loaded).  When the Port Arbitration Table
+ * Status clears, hardware has latched the table into port arbitration logic.
+ */
+static void pci_vc_load_port_arb_table(struct pci_dev *dev, int pos, int res)
+{
+	int ctrl_pos, status_pos;
+	u32 ctrl;
+
+	ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+	status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+
+	pci_read_config_dword(dev, ctrl_pos, &ctrl);
+	pci_write_config_dword(dev, ctrl_pos,
+			       ctrl | PCI_VC_RES_CTRL_LOAD_TABLE);
+
+	if (pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_TABLE))
+		return;
+
+	dev_err(&dev->dev, "VC%d port arbitration table failed to load\n", res);
+}
+
+/**
+ * pci_vc_enable - Enable virtual channel
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @res: VC res number, ie. VCn (0-7)
+ *
+ * A VC is enabled by setting the enable bit in matching resource control
+ * registers on both sides of a link.  We therefore need to find the opposite
+ * end of the link.  To keep this simple we enable from the downstream device.
+ * RC devices do not have an upstream device, nor does it seem that VC9 do
+ * (spec is unclear).  Once we find the upstream device, match the VC ID to
+ * get the correct resource, disable and enable on both ends.
+ */
+static void pci_vc_enable(struct pci_dev *dev, int pos, int res)
+{
+	int ctrl_pos, status_pos, id, pos2, evcc, i, ctrl_pos2, status_pos2;
+	u32 ctrl, header, cap1, ctrl2;
+	struct pci_dev *link = NULL;
+
+	/* Enable VCs from the downstream device */
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
+	    pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)
+		return;
+
+	ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+	status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+
+	pci_read_config_dword(dev, ctrl_pos, &ctrl);
+	id = ctrl & PCI_VC_RES_CTRL_ID;
+
+	pci_read_config_dword(dev, pos, &header);
+
+	/* If there is no opposite end of the link, skip to enable */
+	if (PCI_EXT_CAP_ID(header) == PCI_EXT_CAP_ID_VC9 ||
+	    pci_is_root_bus(dev->bus))
+		goto enable;
+
+	pos2 = pci_find_ext_capability(dev->bus->self, PCI_EXT_CAP_ID_VC);
+	if (!pos2)
+		goto enable;
+
+	pci_read_config_dword(dev->bus->self, pos2 + PCI_VC_PORT_CAP1, &cap1);
+	evcc = cap1 & PCI_VC_CAP1_EVCC;
+
+	/* VC0 is hardwired enabled, so we can start with 1 */
+	for (i = 1; i < evcc + 1; i++) {
+		ctrl_pos2 = pos2 + PCI_VC_RES_CTRL +
+				(i * PCI_CAP_VC_PER_VC_SIZEOF);
+		status_pos2 = pos2 + PCI_VC_RES_STATUS +
+				(i * PCI_CAP_VC_PER_VC_SIZEOF);
+		pci_read_config_dword(dev->bus->self, ctrl_pos2, &ctrl2);
+		if ((ctrl2 & PCI_VC_RES_CTRL_ID) == id) {
+			link = dev->bus->self;
+			break;
+		}
+	}
+
+	if (!link)
+		goto enable;
+
+	/* Disable if enabled */
+	if (ctrl2 & PCI_VC_RES_CTRL_ENABLE) {
+		ctrl2 &= ~PCI_VC_RES_CTRL_ENABLE;
+		pci_write_config_dword(link, ctrl_pos2, ctrl2);
+	}
+
+	/* Enable on both ends */
+	ctrl2 |= PCI_VC_RES_CTRL_ENABLE;
+	pci_write_config_dword(link, ctrl_pos2, ctrl2);
+enable:
+	ctrl |= PCI_VC_RES_CTRL_ENABLE;
+	pci_write_config_dword(dev, ctrl_pos, ctrl);
+
+	if (!pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_NEGO))
+		dev_err(&dev->dev, "VC%d negotiation stuck pending\n", id);
+
+	if (link && !pci_wait_for_pending(link, status_pos2,
+					  PCI_VC_RES_STATUS_NEGO))
+		dev_err(&link->dev, "VC%d negotiation stuck pending\n", id);
+}
+
+/**
+ * pci_vc_do_save_buffer - Size, save, or restore VC state
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @save_state: buffer for save/restore
+ * @name: for error message
+ * @save: if provided a buffer, this indicates what to do with it
+ *
+ * Walking Virtual Channel config space to size, save, or restore it
+ * is complicated, so we do it all from one function to reduce code and
+ * guarantee ordering matches in the buffer.  When called with NULL
+ * @save_state, return the size of the necessary save buffer.  When called
+ * with a non-NULL @save_state, @save determines whether we save to the
+ * buffer or restore from it.
+ */
+static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos,
+				 struct pci_cap_saved_state *save_state,
+				 bool save)
+{
+	u32 cap1;
+	char evcc, lpevcc, parb_size;
+	int i, len = 0;
+	u8 *buf = save_state ? (u8 *)save_state->cap.data : NULL;
+
+	/* Sanity check buffer size for save/restore */
+	if (buf && save_state->cap.size !=
+	    pci_vc_do_save_buffer(dev, pos, NULL, save)) {
+		dev_err(&dev->dev,
+			"VC save buffer size does not match @0x%x\n", pos);
+		return -ENOMEM;
+	}
+
+	pci_read_config_dword(dev, pos + PCI_VC_PORT_CAP1, &cap1);
+	/* Extended VC Count (not counting VC0) */
+	evcc = cap1 & PCI_VC_CAP1_EVCC;
+	/* Low Priority Extended VC Count (not counting VC0) */
+	lpevcc = (cap1 & PCI_VC_CAP1_LPEVCC) >> 4;
+	/* Port Arbitration Table Entry Size (bits) */
+	parb_size = 1 << ((cap1 & PCI_VC_CAP1_ARB_SIZE) >> 10);
+
+	/*
+	 * Port VC Control Register contains VC Arbitration Select, which
+	 * cannot be modified when more than one LPVC is in operation.  We
+	 * therefore save/restore it first, as only VC0 should be enabled
+	 * after device reset.
+	 */
+	if (buf) {
+		if (save)
+			pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL,
+					     (u16 *)buf);
+		else
+			pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL,
+					      *(u16 *)buf);
+		buf += 2;
+	}
+	len += 2;
+
+	/*
+	 * If we have any Low Priority VCs and a VC Arbitration Table Offset
+	 * in Port VC Capability Register 2 then save/restore it next.
+	 */
+	if (lpevcc) {
+		u32 cap2;
+		int vcarb_offset;
+
+		pci_read_config_dword(dev, pos + PCI_VC_PORT_CAP2, &cap2);
+		vcarb_offset = ((cap2 & PCI_VC_CAP2_ARB_OFF) >> 24) * 16;
+
+		if (vcarb_offset) {
+			int size, vcarb_phases = 0;
+
+			if (cap2 & PCI_VC_CAP2_128_PHASE)
+				vcarb_phases = 128;
+			else if (cap2 & PCI_VC_CAP2_64_PHASE)
+				vcarb_phases = 64;
+			else if (cap2 & PCI_VC_CAP2_32_PHASE)
+				vcarb_phases = 32;
+
+			/* Fixed 4 bits per phase per lpevcc (plus VC0) */
+			size = ((lpevcc + 1) * vcarb_phases * 4) / 8;
+
+			if (size && buf) {
+				pci_vc_save_restore_dwords(dev,
+							   pos + vcarb_offset,
+							   (u32 *)buf,
+							   size / 4, save);
+				/*
+				 * On restore, we need to signal hardware to
+				 * re-load the VC Arbitration Table.
+				 */
+				if (!save)
+					pci_vc_load_arb_table(dev, pos);
+
+				buf += size;
+			}
+			len += size;
+		}
+	}
+
+	/*
+	 * In addition to each VC Resource Control Register, we may have a
+	 * Port Arbitration Table attached to each VC.  The Port Arbitration
+	 * Table Offset in each VC Resource Capability Register tells us if
+	 * it exists.  The entry size is global from the Port VC Capability
+	 * Register1 above.  The number of phases is determined per VC.
+	 */
+	for (i = 0; i < evcc + 1; i++) {
+		u32 cap;
+		int parb_offset;
+
+		pci_read_config_dword(dev, pos + PCI_VC_RES_CAP +
+				      (i * PCI_CAP_VC_PER_VC_SIZEOF), &cap);
+		parb_offset = ((cap & PCI_VC_RES_CAP_ARB_OFF) >> 24) * 16;
+		if (parb_offset) {
+			int size, parb_phases = 0;
+
+			if (cap & PCI_VC_RES_CAP_256_PHASE)
+				parb_phases = 256;
+			else if (cap & (PCI_VC_RES_CAP_128_PHASE |
+					PCI_VC_RES_CAP_128_PHASE_TB))
+				parb_phases = 128;
+			else if (cap & PCI_VC_RES_CAP_64_PHASE)
+				parb_phases = 64;
+			else if (cap & PCI_VC_RES_CAP_32_PHASE)
+				parb_phases = 32;
+
+			size = (parb_size * parb_phases) / 8;
+
+			if (size && buf) {
+				pci_vc_save_restore_dwords(dev,
+							   pos + parb_offset,
+							   (u32 *)buf,
+							   size / 4, save);
+				buf += size;
+			}
+			len += size;
+		}
+
+		/* VC Resource Control Register */
+		if (buf) {
+			int ctrl_pos = pos + PCI_VC_RES_CTRL +
+						(i * PCI_CAP_VC_PER_VC_SIZEOF);
+			if (save)
+				pci_read_config_dword(dev, ctrl_pos,
+						      (u32 *)buf);
+			else {
+				u32 tmp, ctrl = *(u32 *)buf;
+				/*
+				 * For an FLR case, the VC config may remain.
+				 * Preserve enable bit, restore the rest.
+				 */
+				pci_read_config_dword(dev, ctrl_pos, &tmp);
+				tmp &= PCI_VC_RES_CTRL_ENABLE;
+				tmp |= ctrl & ~PCI_VC_RES_CTRL_ENABLE;
+				pci_write_config_dword(dev, ctrl_pos, tmp);
+				/* Load port arbitration table if used */
+				if (ctrl & PCI_VC_RES_CTRL_ARB_SELECT)
+					pci_vc_load_port_arb_table(dev, pos, i);
+				/* Re-enable if needed */
+				if ((ctrl ^ tmp) & PCI_VC_RES_CTRL_ENABLE)
+					pci_vc_enable(dev, pos, i);
+			}
+			buf += 4;
+		}
+		len += 4;
+	}
+
+	return buf ? 0 : len;
+}
+
+static struct {
+	u16 id;
+	const char *name;
+} vc_caps[] = { { PCI_EXT_CAP_ID_MFVC, "MFVC" },
+		{ PCI_EXT_CAP_ID_VC, "VC" },
+		{ PCI_EXT_CAP_ID_VC9, "VC9" } };
+
+/**
+ * pci_save_vc_state - Save VC state to pre-allocate save buffer
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability and
+ * save it to the pre-allocated save buffer.
+ */
+int pci_save_vc_state(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+		int pos, ret;
+		struct pci_cap_saved_state *save_state;
+
+		pos = pci_find_ext_capability(dev, vc_caps[i].id);
+		if (!pos)
+			continue;
+
+		save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id);
+		if (!save_state) {
+			dev_err(&dev->dev, "%s buffer not found in %s\n",
+				vc_caps[i].name, __func__);
+			return -ENOMEM;
+		}
+
+		ret = pci_vc_do_save_buffer(dev, pos, save_state, true);
+		if (ret) {
+			dev_err(&dev->dev, "%s save unsuccessful %s\n",
+				vc_caps[i].name, __func__);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * pci_restore_vc_state - Restore VC state from save buffer
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability and
+ * restore it from the previously saved buffer.
+ */
+void pci_restore_vc_state(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+		int pos;
+		struct pci_cap_saved_state *save_state;
+
+		pos = pci_find_ext_capability(dev, vc_caps[i].id);
+		save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id);
+		if (!save_state || !pos)
+			continue;
+
+		pci_vc_do_save_buffer(dev, pos, save_state, false);
+	}
+}
+
+/**
+ * pci_allocate_vc_save_buffers - Allocate save buffers for VC caps
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability, size
+ * it, and allocate a buffer for save/restore.
+ */
+
+void pci_allocate_vc_save_buffers(struct pci_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+		int len, pos = pci_find_ext_capability(dev, vc_caps[i].id);
+
+		if (!pos)
+			continue;
+
+		len = pci_vc_do_save_buffer(dev, pos, NULL, false);
+		if (pci_add_ext_cap_save_buffer(dev, vc_caps[i].id, len))
+			dev_err(&dev->dev,
+				"unable to preallocate %s save buffer\n",
+				vc_caps[i].name);
+	}
+}

drivers/vfio/pci/vfio_pci_config.c

@@ -975,20 +975,20 @@ static int vfio_vc_cap_len(struct vfio_pci_device *vdev, u16 pos)
 	int ret, evcc, phases, vc_arb;
 	int len = PCI_CAP_VC_BASE_SIZEOF;
 
-	ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_REG1, &tmp);
+	ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP1, &tmp);
 	if (ret)
 		return pcibios_err_to_errno(ret);
 
-	evcc = tmp & PCI_VC_REG1_EVCC; /* extended vc count */
-	ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_REG2, &tmp);
+	evcc = tmp & PCI_VC_CAP1_EVCC; /* extended vc count */
+	ret = pci_read_config_dword(pdev, pos + PCI_VC_PORT_CAP2, &tmp);
 	if (ret)
 		return pcibios_err_to_errno(ret);
 
-	if (tmp & PCI_VC_REG2_128_PHASE)
+	if (tmp & PCI_VC_CAP2_128_PHASE)
 		phases = 128;
-	else if (tmp & PCI_VC_REG2_64_PHASE)
+	else if (tmp & PCI_VC_CAP2_64_PHASE)
 		phases = 64;
-	else if (tmp & PCI_VC_REG2_32_PHASE)
+	else if (tmp & PCI_VC_CAP2_32_PHASE)
 		phases = 32;
 	else
 		phases = 0;

include/linux/pci.h

@@ -224,7 +224,8 @@ enum pci_bus_speed {
 };
 
 struct pci_cap_saved_data {
-	char cap_nr;
+	u16 cap_nr;
+	bool cap_extended;
 	unsigned int size;
 	u32 data[0];
 };
@@ -938,6 +939,7 @@ bool pci_check_and_unmask_intx(struct pci_dev *dev);
 void pci_msi_off(struct pci_dev *dev);
 int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size);
 int pci_set_dma_seg_boundary(struct pci_dev *dev, unsigned long mask);
+int pci_wait_for_pending(struct pci_dev *dev, int pos, u16 mask);
 int pci_wait_for_pending_transaction(struct pci_dev *dev);
 int pcix_get_max_mmrbc(struct pci_dev *dev);
 int pcix_get_mmrbc(struct pci_dev *dev);
@@ -976,6 +978,12 @@ struct pci_saved_state *pci_store_saved_state(struct pci_dev *dev);
 int pci_load_saved_state(struct pci_dev *dev, struct pci_saved_state *state);
 int pci_load_and_free_saved_state(struct pci_dev *dev,
 				  struct pci_saved_state **state);
+struct pci_cap_saved_state *pci_find_saved_cap(struct pci_dev *dev, char cap);
+struct pci_cap_saved_state *pci_find_saved_ext_cap(struct pci_dev *dev,
+						   u16 cap);
+int pci_add_cap_save_buffer(struct pci_dev *dev, char cap, unsigned int size);
+int pci_add_ext_cap_save_buffer(struct pci_dev *dev,
+				u16 cap, unsigned int size);
 int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state);
 int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
 pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);
@@ -997,6 +1005,11 @@ static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state,
 	return __pci_enable_wake(dev, state, false, enable);
 }
 
+/* PCI Virtual Channel */
+int pci_save_vc_state(struct pci_dev *dev);
+void pci_restore_vc_state(struct pci_dev *dev);
+void pci_allocate_vc_save_buffers(struct pci_dev *dev);
+
 #define PCI_EXP_IDO_REQUEST	(1<<0)
 #define PCI_EXP_IDO_COMPLETION	(1<<1)
 void pci_enable_ido(struct pci_dev *dev, unsigned long type);

include/uapi/linux/pci_regs.h

@@ -685,17 +685,34 @@
 #define PCI_ERR_ROOT_ERR_SRC	52	/* Error Source Identification */
 
 /* Virtual Channel */
-#define PCI_VC_PORT_REG1	4
-#define  PCI_VC_REG1_EVCC	0x7	/* extended VC count */
-#define PCI_VC_PORT_REG2	8
-#define  PCI_VC_REG2_32_PHASE	0x2
-#define  PCI_VC_REG2_64_PHASE	0x4
-#define  PCI_VC_REG2_128_PHASE	0x8
+#define PCI_VC_PORT_CAP1	4
+#define  PCI_VC_CAP1_EVCC	0x00000007	/* extended VC count */
+#define  PCI_VC_CAP1_LPEVCC	0x00000070	/* low prio extended VC count */
+#define  PCI_VC_CAP1_ARB_SIZE	0x00000c00
+#define PCI_VC_PORT_CAP2	8
+#define  PCI_VC_CAP2_32_PHASE		0x00000002
+#define  PCI_VC_CAP2_64_PHASE		0x00000004
+#define  PCI_VC_CAP2_128_PHASE		0x00000008
+#define  PCI_VC_CAP2_ARB_OFF		0xff000000
 #define PCI_VC_PORT_CTRL	12
+#define  PCI_VC_PORT_CTRL_LOAD_TABLE	0x00000001
 #define PCI_VC_PORT_STATUS	14
+#define  PCI_VC_PORT_STATUS_TABLE	0x00000001
 #define PCI_VC_RES_CAP		16
+#define  PCI_VC_RES_CAP_32_PHASE	0x00000002
+#define  PCI_VC_RES_CAP_64_PHASE	0x00000004
+#define  PCI_VC_RES_CAP_128_PHASE	0x00000008
+#define  PCI_VC_RES_CAP_128_PHASE_TB	0x00000010
+#define  PCI_VC_RES_CAP_256_PHASE	0x00000020
+#define  PCI_VC_RES_CAP_ARB_OFF		0xff000000
 #define PCI_VC_RES_CTRL		20
+#define  PCI_VC_RES_CTRL_LOAD_TABLE	0x00010000
+#define  PCI_VC_RES_CTRL_ARB_SELECT	0x000e0000
+#define  PCI_VC_RES_CTRL_ID		0x07000000
+#define  PCI_VC_RES_CTRL_ENABLE		0x80000000
 #define PCI_VC_RES_STATUS	26
+#define  PCI_VC_RES_STATUS_TABLE	0x00000001
+#define  PCI_VC_RES_STATUS_NEGO		0x00000002
 #define PCI_CAP_VC_BASE_SIZEOF		0x10
 #define PCI_CAP_VC_PER_VC_SIZEOF	0x0C