[PATCH 2/3] PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()

[Niklas Cassel <cassel@kernel.org>]

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().

Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index bed7c7d1fe3c3..c69c133701c92 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -609,10 +609,17 @@ 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) ||
-- 
2.47.0