[PATCH 5.4 261/320] PCI: pci-bridge-emul: Properly mark reserved PCIe bits in PCI config space

Greg Kroah-Hartman
2022-01-24T20:18:02Z

From: Pali Rohár <pali@kernel.org>

commit 7b067ac63a5730d2fae18399fed7e45f23d36912 upstream.

Some bits in PCI config space are reserved when device is PCIe. Properly
define behavior of PCI registers for PCIe emulated bridge and ensure that
it would not be possible change these reserved bits.

Link: https://lore.kernel.org/r/20211124155944.1290-3-pali@kernel.org
Fixes: 23a5fba4d941 ("PCI: Introduce PCI bridge emulated config space common logic")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/pci-bridge-emul.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -300,6 +300,27 @@ int pci_bridge_emul_init(struct pci_brid
kfree(bridge->pci_regs_behavior);
return -ENOMEM;
}
+ /* These bits are applicable only for PCI and reserved on PCIe */
+ bridge->pci_regs_behavior[PCI_CACHE_LINE_SIZE / 4].ro &=
+ ~GENMASK(15, 8);
+ bridge->pci_regs_behavior[PCI_COMMAND / 4].ro &=
+ ~((PCI_COMMAND_SPECIAL | PCI_COMMAND_INVALIDATE |
+ PCI_COMMAND_VGA_PALETTE | PCI_COMMAND_WAIT |
+ PCI_COMMAND_FAST_BACK) |
+ (PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK |
+ PCI_STATUS_DEVSEL_MASK) << 16);
+ bridge->pci_regs_behavior[PCI_PRIMARY_BUS / 4].ro &=
+ ~GENMASK(31, 24);
+ bridge->pci_regs_behavior[PCI_IO_BASE / 4].ro &=
+ ~((PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK |
+ PCI_STATUS_DEVSEL_MASK) << 16);
+ bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].rw &=
+ ~((PCI_BRIDGE_CTL_MASTER_ABORT |
+ BIT(8) | BIT(9) | BIT(11)) << 16);
+ bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].ro &=
+ ~((PCI_BRIDGE_CTL_FAST_BACK) << 16);
+ bridge->pci_regs_behavior[PCI_INTERRUPT_LINE / 4].w1c &=
+ ~(BIT(10) << 16);
}

if (flags & PCI_BRIDGE_EMUL_NO_PREFETCHABLE_BAR) {