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[PATCH 1/7] drivers:hv: Lock access to hyperv_mmio resource tree

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  [PATCH 1/7] drivers:hv: Lock access to hyperv_mmio resource tree "K. Y. Srinivasan" <kys@microsoft.com> - 2016-04-05 17:50 +0200
    [PATCH 6/7] drivers:hv: Record MMIO range in use by frame buffer "K. Y. Srinivasan" <kys@microsoft.com> - 2016-04-05 17:50 +0200
    [PATCH 5/7] drivers:hv: Track allocations of children of hv_vmbus in private resource tree "K. Y. Srinivasan" <kys@microsoft.com> - 2016-04-05 17:50 +0200
    [PATCH 4/7] drivers:hv: Reverse order of resources in hyperv_mmio "K. Y. Srinivasan" <kys@microsoft.com> - 2016-04-05 17:50 +0200
    [PATCH 3/7] drivers:hv: Use new vmbus_mmio_free() from client drivers. "K. Y. Srinivasan" <kys@microsoft.com> - 2016-04-05 17:50 +0200

#1371738 — [PATCH 1/7] drivers:hv: Lock access to hyperv_mmio resource tree

From: Jake Oshins <jakeo@microsoft.com>

In existing code, this tree of resources is created
in single-threaded code and never modified after it is
created, and thus needs no locking.  This patch introduces
a semaphore for tree access, as other patches in this
series introduce run-time modifications of this resource
tree which can happen on multiple threads.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
Greg, please apply this to the 4.6 tree.

 drivers/hv/vmbus_drv.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 64713ff..799518b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -102,6 +102,7 @@ static struct notifier_block hyperv_panic_block = {
 };
 
 struct resource *hyperv_mmio;
+DEFINE_SEMAPHORE(hyperv_mmio_lock);
 
 static int vmbus_exists(void)
 {
@@ -1132,7 +1133,10 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 	resource_size_t range_min, range_max, start, local_min, local_max;
 	const char *dev_n = dev_name(&device_obj->device);
 	u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
-	int i;
+	int i, retval;
+
+	retval = -ENXIO;
+	down(&hyperv_mmio_lock);
 
 	for (iter = hyperv_mmio; iter; iter = iter->sibling) {
 		if ((iter->start >= max) || (iter->end <= min))
@@ -1169,13 +1173,17 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			for (; start + size - 1 <= local_max; start += align) {
 				*new = request_mem_region_exclusive(start, size,
 								    dev_n);
-				if (*new)
-					return 0;
+				if (*new) {
+					retval = 0;
+					goto exit;
+				}
 			}
 		}
 	}
 
-	return -ENXIO;
+exit:
+	up(&hyperv_mmio_lock);
+	return retval;
 }
 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
 
-- 
1.7.4.1

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#1371741 — [PATCH 6/7] drivers:hv: Record MMIO range in use by frame buffer

From: Jake Oshins <jakeo@microsoft.com>

Later in the boot sequence, we need to figure out which memory
ranges can be given out to various paravirtual drivers.  The
hyperv_fb driver should, ideally, be placed right on top of
the frame buffer, without some other device getting plopped on
top of this range in the meantime.  Recording this now allows
that to be guaranteed.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
	Greg, please apply this to the 4.6 tree.

 drivers/hv/vmbus_drv.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index dfc6149..eaa5c3b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -41,6 +41,7 @@
 #include <linux/ptrace.h>
 #include <linux/screen_info.h>
 #include <linux/kdebug.h>
+#include <linux/efi.h>
 #include "hyperv_vmbus.h"
 
 static struct acpi_device  *hv_acpi_dev;
@@ -101,6 +102,8 @@ static struct notifier_block hyperv_panic_block = {
 	.notifier_call = hyperv_panic_event,
 };
 
+static const char *fb_mmio_name = "fb_range";
+static struct resource *fb_mmio;
 struct resource *hyperv_mmio;
 DEFINE_SEMAPHORE(hyperv_mmio_lock);
 
@@ -1091,6 +1094,12 @@ static int vmbus_acpi_remove(struct acpi_device *device)
 	struct resource *next_res;
 
 	if (hyperv_mmio) {
+		if (fb_mmio) {
+			__release_region(hyperv_mmio, fb_mmio->start,
+					 resource_size(fb_mmio));
+			fb_mmio = NULL;
+		}
+
 		for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
 			next_res = cur_res->sibling;
 			kfree(cur_res);
@@ -1100,6 +1109,30 @@ static int vmbus_acpi_remove(struct acpi_device *device)
 	return 0;
 }
 
+static void vmbus_reserve_fb(void)
+{
+	int size;
+	/*
+	 * Make a claim for the frame buffer in the resource tree under the
+	 * first node, which will be the one below 4GB.  The length seems to
+	 * be underreported, particularly in a Generation 1 VM.  So start out
+	 * reserving a larger area and make it smaller until it succeeds.
+	 */
+
+	if (screen_info.lfb_base) {
+		if (efi_enabled(EFI_BOOT))
+			size = max_t(__u32, screen_info.lfb_size, 0x800000);
+		else
+			size = max_t(__u32, screen_info.lfb_size, 0x4000000);
+
+		for (; !fb_mmio && (size >= 0x100000); size >>= 1) {
+			fb_mmio = __request_region(hyperv_mmio,
+						   screen_info.lfb_base, size,
+						   fb_mmio_name, 0);
+		}
+	}
+}
+
 /**
  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
  * @new:		If successful, supplied a pointer to the
@@ -1261,8 +1294,10 @@ static int vmbus_acpi_add(struct acpi_device *device)
 
 		if (ACPI_FAILURE(result))
 			continue;
-		if (hyperv_mmio)
+		if (hyperv_mmio) {
+			vmbus_reserve_fb();
 			break;
+		}
 	}
 	ret_val = 0;
 
-- 
1.7.4.1

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#1371743 — [PATCH 5/7] drivers:hv: Track allocations of children of hv_vmbus in private resource tree

From: Jake Oshins <jakeo@microsoft.com>

This patch changes vmbus_allocate_mmio() and vmbus_free_mmio() so
that when child paravirtual devices allocate memory-mapped I/O
space, they allocate it privately from a resource tree pointed
at by hyperv_mmio and also by the public resource tree
iomem_resource.  This allows the region to be marked as "busy"
in the private tree, but a "bridge window" in the public tree,
guaranteeing that no two bridge windows will overlap each other
but while also allowing the PCI device children of the bridge
windows to overlap that window.

One might conclude that this belongs in the pnp layer, rather
than in this driver.  Rafael Wysocki, the maintainter of the
pnp layer, has previously asked that we not modify the pnp layer
as it is considered deprecated.  This patch is thus essentially
a workaround.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
	Greg, please apply this to the 4.6 tree.

 drivers/hv/vmbus_drv.c |   22 +++++++++++++++++++++-
 1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 1ce47d0..dfc6149 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1128,7 +1128,7 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			resource_size_t size, resource_size_t align,
 			bool fb_overlap_ok)
 {
-	struct resource *iter;
+	struct resource *iter, *shadow;
 	resource_size_t range_min, range_max, start, local_min, local_max;
 	const char *dev_n = dev_name(&device_obj->device);
 	u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
@@ -1170,12 +1170,22 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 
 			start = (local_min + align - 1) & ~(align - 1);
 			for (; start + size - 1 <= local_max; start += align) {
+				shadow = __request_region(iter, start,
+							  size,
+							  NULL,
+							  IORESOURCE_BUSY);
+				if (!shadow)
+					continue;
+
 				*new = request_mem_region_exclusive(start, size,
 								    dev_n);
 				if (*new) {
+					shadow->name = (char *)*new;
 					retval = 0;
 					goto exit;
 				}
+
+				__release_region(iter, start, size);
 			}
 		}
 	}
@@ -1196,7 +1206,17 @@ EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
  */
 void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 {
+	struct resource *iter;
+
+	down(&hyperv_mmio_lock);
+	for (iter = hyperv_mmio; iter; iter = iter->sibling) {
+		if ((iter->start >= start + size) || (iter->end <= start))
+			continue;
+
+		__release_region(iter, start, size);
+	}
 	release_mem_region(start, size);
+	up(&hyperv_mmio_lock);
 
 }
 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
-- 
1.7.4.1

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#1371744 — [PATCH 4/7] drivers:hv: Reverse order of resources in hyperv_mmio

From: Jake Oshins <jakeo@microsoft.com>

A patch later in this series allocates child nodes
in this resource tree.  For that to work, this tree
needs to be sorted in ascending order.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
	Greg, please apply this to the 4.6 tree.

 drivers/hv/vmbus_drv.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 60553c1..1ce47d0 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1049,7 +1049,6 @@ static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 	new_res->end = end;
 
 	/*
-	 * Stick ranges from higher in address space at the front of the list.
 	 * If two ranges are adjacent, merge them.
 	 */
 	do {
@@ -1070,7 +1069,7 @@ static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 			break;
 		}
 
-		if ((*old_res)->end < new_res->start) {
+		if ((*old_res)->start > new_res->end) {
 			new_res->sibling = *old_res;
 			if (prev_res)
 				(*prev_res)->sibling = new_res;
-- 
1.7.4.1

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#1371745 — [PATCH 3/7] drivers:hv: Use new vmbus_mmio_free() from client drivers.

From: Jake Oshins <jakeo@microsoft.com>

This patch modifies all the callers of vmbus_mmio_allocate()
to call vmbus_mmio_free() instead of release_mem_region().

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
	Greg, please apply this to the 4.6 tree.

 drivers/pci/host/pci-hyperv.c   |   14 +++++++-------
 drivers/video/fbdev/hyperv_fb.c |    4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index ed651ba..f2559b6 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1795,14 +1795,14 @@ static void hv_pci_free_bridge_windows(struct hv_pcibus_device *hbus)
 
 	if (hbus->low_mmio_space && hbus->low_mmio_res) {
 		hbus->low_mmio_res->flags |= IORESOURCE_BUSY;
-		release_mem_region(hbus->low_mmio_res->start,
-				   resource_size(hbus->low_mmio_res));
+		vmbus_free_mmio(hbus->low_mmio_res->start,
+				resource_size(hbus->low_mmio_res));
 	}
 
 	if (hbus->high_mmio_space && hbus->high_mmio_res) {
 		hbus->high_mmio_res->flags |= IORESOURCE_BUSY;
-		release_mem_region(hbus->high_mmio_res->start,
-				   resource_size(hbus->high_mmio_res));
+		vmbus_free_mmio(hbus->high_mmio_res->start,
+				resource_size(hbus->high_mmio_res));
 	}
 }
 
@@ -1880,8 +1880,8 @@ static int hv_pci_allocate_bridge_windows(struct hv_pcibus_device *hbus)
 
 release_low_mmio:
 	if (hbus->low_mmio_res) {
-		release_mem_region(hbus->low_mmio_res->start,
-				   resource_size(hbus->low_mmio_res));
+		vmbus_free_mmio(hbus->low_mmio_res->start,
+				resource_size(hbus->low_mmio_res));
 	}
 
 	return ret;
@@ -1924,7 +1924,7 @@ static int hv_allocate_config_window(struct hv_pcibus_device *hbus)
 
 static void hv_free_config_window(struct hv_pcibus_device *hbus)
 {
-	release_mem_region(hbus->mem_config->start, PCI_CONFIG_MMIO_LENGTH);
+	vmbus_free_mmio(hbus->mem_config->start, PCI_CONFIG_MMIO_LENGTH);
 }
 
 /**
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index e2451bd..2fd49b2 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -743,7 +743,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
 err3:
 	iounmap(fb_virt);
 err2:
-	release_mem_region(par->mem->start, screen_fb_size);
+	vmbus_free_mmio(par->mem->start, screen_fb_size);
 	par->mem = NULL;
 err1:
 	if (!gen2vm)
@@ -758,7 +758,7 @@ static void hvfb_putmem(struct fb_info *info)
 	struct hvfb_par *par = info->par;
 
 	iounmap(info->screen_base);
-	release_mem_region(par->mem->start, screen_fb_size);
+	vmbus_free_mmio(par->mem->start, screen_fb_size);
 	par->mem = NULL;
 }
 
-- 
1.7.4.1

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