PCI/IOV: Adjust ->barsz[] when changing BAR size

pci_rebar_set_size() adjusts BAR size for both normal and IOV BARs. The
struct pci_sriov keeps a cached copy of BAR size in ->barsz[] which is not
adjusted by pci_rebar_set_size() but by pci_iov_resource_set_size().
pci_iov_resource_set_size() is called also from
pci_resize_resource_set_size().

The current arrangement is problematic once BAR resize algorithm starts to
roll back changes properly in case of a failure. The normal resource
fitting algorithm rolls back resource size using the struct
pci_dev_resource easily but also calling pci_resize_resource_set_size() or
pci_iov_resource_set_size() to roll back BAR size would be an extra burden,
whereas combining ->barsz[] update with pci_rebar_set_size() naturally
rolls back it when restoring the old BAR size on a different layer of the
BAR resize operation.

Thus, rework pci_rebar_set_size() to also update ->barsz[].

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org> # AVA, AMD GPU
Link: https://patch.msgid.link/20251113162628.5946-3-ilpo.jarvinen@linux.intel.com

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 77dee43b785838d215b58db2d22088e9346e0583..04b675e9096309fcb20e5ef6bcc568e82c1cb9ac 100644 (file)
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -158,8 +158,7 @@ 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)
+void pci_iov_resource_set_size(struct pci_dev *dev, int resno, int size)
 {
        if (!pci_resource_is_iov(resno)) {
                pci_warn(dev, "%s is not an IOV resource\n",
@@ -167,7 +166,8 @@ void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
                return;
        }
 
-       dev->sriov->barsz[pci_resource_num_to_vf_bar(resno)] = size;
+       resno = pci_resource_num_to_vf_bar(resno);
+       dev->sriov->barsz[resno] = pci_rebar_size_to_bytes(size);
 }
 
 bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
@@ -1340,7 +1340,6 @@ EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
 int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
 {
        u32 sizes;
-       int ret;
 
        if (!pci_resource_is_iov(resno))
                return -EINVAL;
@@ -1355,13 +1354,7 @@ int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
        if (!(sizes & BIT(size)))
                return -EINVAL;
 
-       ret = pci_rebar_set_size(dev, resno, size);
-       if (ret)
-               return ret;
-
-       pci_iov_resource_set_size(dev, resno, pci_rebar_size_to_bytes(size));
-
-       return 0;
+       return pci_rebar_set_size(dev, resno, size);
 }
 EXPORT_SYMBOL_GPL(pci_iov_vf_bar_set_size);
 

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b14dd064006cca80ec5275e45a35d6dc2b4d0bbc..7dfc58b0e55ef7f6ab4470f43cc777cdd081dcfd 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3803,6 +3803,10 @@ int pci_rebar_set_size(struct pci_dev *pdev, int bar, int size)
        ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
        ctrl |= FIELD_PREP(PCI_REBAR_CTRL_BAR_SIZE, size);
        pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
+
+       if (pci_resource_is_iov(bar))
+               pci_iov_resource_set_size(pdev, bar, size);
+
        return 0;
 }
 

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4492b809094b5794bd94dfbc20102cb208c3fa2f..bf1a577e962374d109068996c0b824e6dfb9d5bc 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -808,8 +808,7 @@ 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);
+void pci_iov_resource_set_size(struct pci_dev *dev, int resno, int size);
 bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev);
 static inline u16 pci_iov_vf_rebar_cap(struct pci_dev *dev)
 {
@@ -851,7 +850,7 @@ 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) { }
+                                            int size) { }
 static inline bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
 {
        return false;

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index c3ba4ccecd433d414c5423dd8db1fecaf0539c90..3d0b0b3f60c4cee73debd530e631f12eeb3fb4e3 100644 (file)
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -450,12 +450,10 @@ static void pci_resize_resource_set_size(struct pci_dev *dev, int resno,
        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);
-       }
+       if (pci_resource_is_iov(resno))
+               res_size *= pci_sriov_get_totalvfs(dev);
+
+       resource_set_size(res, res_size);
 }
 
 int pci_resize_resource(struct pci_dev *dev, int resno, int size)