While the parameter 'interrupts' to the functions pci_epc_set_msi() and
pci_epc_set_msix() represent the actual number of interrupts, and
pci_epc_get_msi() and pci_epc_get_msix() return the actual number of
interrupts.
These endpoint library functions just mentioned will however supply
"interrupts - 1" to the EPC callback functions pci_epc_ops->set_msi() and
pci_epc_ops->set_msix(), and likewise add 1 to return value from
pci_epc_ops->get_msi() and pci_epc_ops->get_msix(), even though the
parameter name for the callback function is also named 'interrupts'.
While the set_msix() callback function in pcie-designware-ep writes the
Table Size field correctly (N-1), the calculation of the PBA offset
is wrong because it calculates space for (N-1) entries instead of N.
This results in e.g. the following error when using QEMU with PCI
passthrough on a device which relies on the PCI endpoint subsystem:
failed to add PCI capability 0x11[0x50]@0xb0: table & pba overlap, or they don't fit in BARs, or don't align
Fix the calculation of PBA offset in the MSI-X capability.
Fixes: 83153d9f36e2 ("PCI: endpoint: Fix ->set_msix() to take BIR and offset as arguments")
Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-designware-ep.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 1a0bf9341542..24026f3f3413 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -585,6 +585,7 @@ static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
struct dw_pcie_ep_func *ep_func;
u32 val, reg;
+ u16 actual_interrupts = interrupts + 1;
ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
if (!ep_func || !ep_func->msix_cap)
@@ -595,7 +596,7 @@ static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
reg = ep_func->msix_cap + PCI_MSIX_FLAGS;
val = dw_pcie_ep_readw_dbi(ep, func_no, reg);
val &= ~PCI_MSIX_FLAGS_QSIZE;
- val |= interrupts;
+ val |= interrupts; /* 0's based value */
dw_pcie_writew_dbi(pci, reg, val);
reg = ep_func->msix_cap + PCI_MSIX_TABLE;
@@ -603,7 +604,7 @@ static int dw_pcie_ep_set_msix(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
dw_pcie_ep_writel_dbi(ep, func_no, reg, val);
reg = ep_func->msix_cap + PCI_MSIX_PBA;
- val = (offset + (interrupts * PCI_MSIX_ENTRY_SIZE)) | bir;
+ val = (offset + (actual_interrupts * PCI_MSIX_ENTRY_SIZE)) | bir;
dw_pcie_ep_writel_dbi(ep, func_no, reg, val);
dw_pcie_dbi_ro_wr_dis(pci);
--
2.49.0
