According to documentation [0] the correct offset for the Upstream Peer Decode Configuration Register (UPDCR) is 0x1014. It was previously defined as 0x1114. Commit d99321b63b1f intends to enforce isolation between PCI devices allowing them to be put into separate IOMMU groups. Due to the wrong register offset the intended isolation was not fully enforced. This is fixed with this patch. Please note that I did not test this patch because I have no hardware that implements this register. [0] https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/4th-gen-core-family-mobile-i-o-datasheet.pdf (page 325) Fixes: d99321b63b1f ("PCI: Enable quirks for PCIe ACS on Intel PCH root ports") Reviewed-by: Andrew Murray <andrew.murray@xxxxxxx> Signed-off-by: Steffen Liebergeld <steffen.liebergeld@xxxxxxxxxxxxxxx> --- drivers/pci/quirks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 208aacf39329..7e184beb2aa4 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4602,7 +4602,7 @@ int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags) #define INTEL_BSPR_REG_BPPD (1 << 9) /* Upstream Peer Decode Configuration Register */ -#define INTEL_UPDCR_REG 0x1114 +#define INTEL_UPDCR_REG 0x1014 /* 5:0 Peer Decode Enable bits */ #define INTEL_UPDCR_REG_MASK 0x3f -- 2.11.0
