PCI/IOV: Allow IOV resources to be resized in pci_resize_resource()

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

The capability layout is the same as PCI_EXT_CAP_ID_REBAR, which means we
can reuse most of the implementation, the only difference being resource
size calculation (which is multiplied by total VFs) and memory decoding
(which is controlled by a separate VF MSE field in SR-IOV cap).

Extend the pci_resize_resource() function to accept IOV resources.

See PCIe r6.2, sec 7.8.7.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20250702093522.518099-4-michal.winiarski@intel.com

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index bdac0780455255f4d57e65fc0f9099a8490474be..852424cf2ae158f31f4ab9acb7d6f4f6f6007995 100644 (file)
--- 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_num_to_vf_bar(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_num_to_vf_bar(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 e9448d55113bdfd2263d8e2f6b3ec802f56b712e..55695852975b40cc2baccb09ce4ee3710b0ce90a 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3752,7 +3752,13 @@ static int pci_rebar_find_pos(struct pci_dev *pdev, int bar)
        unsigned int pos, nbars, i;
        u32 ctrl;
 
-       pos = pdev->rebar_cap;
+       if (pci_resource_is_iov(bar)) {
+               pos = pci_iov_vf_rebar_cap(pdev);
+               bar = pci_resource_num_to_vf_bar(bar);
+       } else {
+               pos = pdev->rebar_cap;
+       }
+
        if (!pos)
                return -ENOTSUPP;
 

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 190e4c115014ebdabbcce34c600ac60c63e43581..c7430afe75151b65eb82066abfc4c02f03b76431 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -711,6 +711,9 @@ 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 u16 pci_iov_vf_rebar_cap(struct pci_dev *dev)
 {
        if (!dev->is_physfn)
@@ -750,6 +753,12 @@ 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 u16 pci_iov_vf_rebar_cap(struct pci_dev *dev)
 {
        return 0;

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index c6657cdd06f673d390018af574e133ca6a4b0566..d2b3ed51e88048962557bc04038e8b19f40478a6 100644 (file)
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -423,13 +423,39 @@ 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 = pci_resource_n(dev, resno);
+
+       if (!pci_resource_is_iov(resno)) {
+               resource_set_size(res, res_size);
+       } else {
+               resource_set_size(res, res_size * pci_sriov_get_totalvfs(dev));
+               pci_iov_resource_set_size(dev, resno, res_size);
+       }
+}
+
 int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 {
        struct resource *res = pci_resource_n(dev, 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);
@@ -440,8 +466,7 @@ 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);
@@ -459,7 +484,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
        if (ret)
                return ret;
 
-       resource_set_size(res, pci_rebar_size_to_bytes(size));
+       pci_resize_resource_set_size(dev, resno, size);
 
        /* Check if the new config works by trying to assign everything. */
        if (dev->bus->self) {
@@ -471,7 +496,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
 
 error_resize:
        pci_rebar_set_size(dev, resno, old);
-       resource_set_size(res, pci_rebar_size_to_bytes(old));
+       pci_resize_resource_set_size(dev, resno, old);
        return ret;
 }
 EXPORT_SYMBOL(pci_resize_resource);