PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()

A BAR of type BAR_FIXED has a fixed BAR size (the size cannot be changed).

When using pci_epf_alloc_space() to allocate backing memory for a BAR,
pci_epf_alloc_space() will always set the size to the fixed BAR size if
the BAR type is BAR_FIXED (and will give an error if you the requested size
is larger than the fixed BAR size).

However, some drivers might not call pci_epf_alloc_space() before calling
pci_epc_set_bar(), so add a check in pci_epc_set_bar() to ensure that an
EPF driver cannot set a size different from the fixed BAR size, if the BAR
type is BAR_FIXED.

The pci_epc_function_is_valid() check is removed because this check is now
done by pci_epc_get_features().

Link: https://lore.kernel.org/r/20241213143301.4158431-13-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 575a0f208c9521c4a408af0a1c72288c1bef881a..78cc7d47a7d425be9cb92935066cdc128ea2ce4c 100644 (file)
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -600,10 +600,17 @@ EXPORT_SYMBOL_GPL(pci_epc_clear_bar);
 int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
                    struct pci_epf_bar *epf_bar)
 {
-       int ret;
+       const struct pci_epc_features *epc_features;
+       enum pci_barno bar = epf_bar->barno;
        int flags = epf_bar->flags;
+       int ret;
 
-       if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+       epc_features = pci_epc_get_features(epc, func_no, vfunc_no);
+       if (!epc_features)
+               return -EINVAL;
+
+       if (epc_features->bar[bar].type == BAR_FIXED &&
+           (epc_features->bar[bar].fixed_size != epf_bar->size))
                return -EINVAL;
 
        if ((epf_bar->barno == BAR_5 && flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||