[PATCH v4 4/7] PCI: Allow IOV resources to be resized in pci_resize_resource()

[Michał Winiarski]

Similar to regular resizable BAR, VF BAR can also be resized.

The structures are very similar, which means we can reuse most of the
implementation.

Extend the pci_resize_resource() function to accept IOV resources.

See PCIe r4.0, sec 9.3.7.4.

Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
---
 drivers/pci/iov.c       | 21 +++++++++++++++++++++
 drivers/pci/pci.c       | 10 +++++++++-
 drivers/pci/pci.h       | 10 +++++++++-
 drivers/pci/setup-res.c | 36 +++++++++++++++++++++++++++++++-----
 4 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index eedc1df56c49e..79143c1bc7bb4 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -154,6 +154,27 @@ resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
 	return dev->sriov->barsz[pci_resource_from_iov(resno)];
 }
 
+void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
+			       resource_size_t size)
+{
+	if (!pci_resource_is_iov(resno)) {
+		pci_warn(dev, "%s is not an IOV resource\n",
+			 pci_resource_name(dev, resno));
+		return;
+	}
+
+	dev->sriov->barsz[pci_resource_from_iov(resno)] = size;
+}
+
+bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
+{
+	u16 cmd;
+
+	pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd);
+
+	return cmd & PCI_SRIOV_CTRL_MSE;
+}
+
 static void pci_read_vf_config_common(struct pci_dev *virtfn)
 {
 	struct pci_dev *physfn = virtfn->physfn;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7d85c04fbba2a..905a533807b32 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3720,8 +3720,16 @@ static int pci_rebar_find_pos(struct pci_dev *pdev, int bar)
 {
 	unsigned int pos, nbars, i;
 	u32 ctrl;
+	int cap;
 
-	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR);
+	if (pci_resource_is_iov(bar)) {
+		cap = PCI_EXT_CAP_ID_VF_REBAR;
+		bar = pci_resource_from_iov(bar);
+	} else {
+		cap = PCI_EXT_CAP_ID_REBAR;
+	}
+
+	pos = pci_find_ext_capability(pdev, cap);
 	if (!pos)
 		return -ENOTSUPP;
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1f8d88f0243b7..4347858007145 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -580,6 +580,9 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno);
 resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno);
 void pci_restore_iov_state(struct pci_dev *dev);
 int pci_iov_bus_range(struct pci_bus *bus);
+void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
+			       resource_size_t size);
+bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev);
 static inline bool pci_resource_is_iov(int resno)
 {
 	return resno >= PCI_IOV_RESOURCES && resno <= PCI_IOV_RESOURCE_END;
@@ -613,6 +616,12 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
 {
 	return 0;
 }
+static inline void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
+					     resource_size_t size) { }
+static inline bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
+{
+	return false;
+}
 static inline bool pci_resource_is_iov(int resno)
 {
 	return false;
@@ -621,7 +630,6 @@ static inline int pci_resource_to_iov(int resno)
 {
 	return -ENODEV;
 }
-
 static inline int pci_resource_from_iov(int resno)
 {
 	return -ENODEV;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index e2cf79253ebda..cec8f684b7c70 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -425,13 +425,40 @@ void pci_release_resource(struct pci_dev *dev, int resno)
 }
 EXPORT_SYMBOL(pci_release_resource);
 
+static bool pci_resize_is_memory_decoding_enabled(struct pci_dev *dev,
+						  int resno)
+{
+	u16 cmd;
+
+	if (pci_resource_is_iov(resno))
+		return pci_iov_is_memory_decoding_enabled(dev);
+
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+
+	return cmd & PCI_COMMAND_MEMORY;
+}
+
+static void pci_resize_resource_set_size(struct pci_dev *dev, int resno,
+					 int size)
+{
+	resource_size_t res_size = pci_rebar_size_to_bytes(size);
+	struct resource *res = dev->resource + resno;
+
+	if (!pci_resource_is_iov(resno)) {
+		res->end = res->start + res_size - 1;
+	} else {
+		res->end = res->start +
+			res_size * pci_sriov_get_totalvfs(dev) - 1;
+		pci_iov_resource_set_size(dev, resno, res_size);
+	}
+}
+
 int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 {
 	struct resource *res = dev->resource + resno;
 	struct pci_host_bridge *host;
 	int old, ret;
 	u32 sizes;
-	u16 cmd;
 
 	/* Check if we must preserve the firmware's resource assignment */
 	host = pci_find_host_bridge(dev->bus);
@@ -442,8 +469,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 	if (!(res->flags & IORESOURCE_UNSET))
 		return -EBUSY;
 
-	pci_read_config_word(dev, PCI_COMMAND, &cmd);
-	if (cmd & PCI_COMMAND_MEMORY)
+	if (pci_resize_is_memory_decoding_enabled(dev, resno))
 		return -EBUSY;
 
 	sizes = pci_rebar_get_possible_sizes(dev, resno);
@@ -461,7 +487,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 	if (ret)
 		return ret;
 
-	res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
+	pci_resize_resource_set_size(dev, resno, size);
 
 	/* Check if the new config works by trying to assign everything. */
 	if (dev->bus->self) {
@@ -473,7 +499,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 
 error_resize:
 	pci_rebar_set_size(dev, resno, old);
-	res->end = res->start + pci_rebar_size_to_bytes(old) - 1;
+	pci_resize_resource_set_size(dev, resno, old);
 	return ret;
 }
 EXPORT_SYMBOL(pci_resize_resource);
-- 
2.47.0