6.15-stable review patch. If anyone has any objections, please let me know.
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From: Niklas Cassel cassel@kernel.org
commit c8bcb01352a86bc5592403904109c22b66bd916e upstream.
While cdns_pcie_ep_set_msix() 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 the following QEMU error when using 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.
[bhelgaas: more specific subject and commit log]
Fixes: 3ef5d16f50f8 ("PCI: cadence: Add MSI-X support to Endpoint driver") Signed-off-by: Niklas Cassel cassel@kernel.org Signed-off-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Wilfred Mallawa wilfred.mallawa@wdc.com Reviewed-by: Damien Le Moal dlemoal@kernel.org Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250514074313.283156-10-cassel@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/controller/cadence/pcie-cadence-ep.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c @@ -292,13 +292,14 @@ static int cdns_pcie_ep_set_msix(struct struct cdns_pcie *pcie = &ep->pcie; u32 cap = CDNS_PCIE_EP_FUNC_MSIX_CAP_OFFSET; u32 val, reg; + u16 actual_interrupts = interrupts + 1;
fn = cdns_pcie_get_fn_from_vfn(pcie, fn, vfn);
reg = cap + PCI_MSIX_FLAGS; val = cdns_pcie_ep_fn_readw(pcie, fn, reg); val &= ~PCI_MSIX_FLAGS_QSIZE; - val |= interrupts; + val |= interrupts; /* 0's based value */ cdns_pcie_ep_fn_writew(pcie, fn, reg, val);
/* Set MSI-X BAR and offset */ @@ -308,7 +309,7 @@ static int cdns_pcie_ep_set_msix(struct
/* Set PBA BAR and offset. BAR must match MSI-X BAR */ reg = cap + PCI_MSIX_PBA; - val = (offset + (interrupts * PCI_MSIX_ENTRY_SIZE)) | bir; + val = (offset + (actual_interrupts * PCI_MSIX_ENTRY_SIZE)) | bir; cdns_pcie_ep_fn_writel(pcie, fn, reg, val);
return 0;