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IsPciDeviceRejected() masks BAR value with 0xFFFFFFF0 before testing the type bits (2:1) that mark a 64-bit memory BAR, essentially clears them, making the 64-bit BAR code path unreachable and treated as if it were 32-bit. The function rejects a device when BAR looks unprogrammed by comparing if its size mask equals its value. When a 64-bit BAR is mistaken for a 32-bit one, only its lower part is compared, possibly leading a valid BAR being falsely rejected. For example, a 2G BAR with size mask 0x80000000 at 0x180000000 matches and the device is dropped. This code runs during light enumeration (PciEnumeratorLight), used when PCI resources are already assigned by the platform (e.g. Xen HVM, where hvmloader programs the BARs). The rejected device never receives a PciIo handle, so no driver can bind to it. For example, a virtio-vga with a 64-bit BAR vanishes under OVMF on Xen, leaving the guest with no graphics output. Fix by testing the type bits on the raw BAR value before masking. Signed-off-by: Jiaqing Zhao <Zhao.Jiaqing@amd.com> |
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| Application | ||
| Bus | ||
| Core | ||
| Include | ||
| Library | ||
| Logo | ||
| Test | ||
| Universal | ||
| MdeModulePkg.ci.yaml | ||
| MdeModulePkg.dec | ||
| MdeModulePkg.dsc | ||
| MdeModulePkg.uni | ||
| MdeModulePkgExtra.uni | ||