Hi Stewart, > On 12 Jul 2023, at 2:52 pm, Stewart Hildebrand <[email protected]> > wrote: > > When mapping BARs for vPCI, it's valid for a BAR mfn_t start to equal the BAR > mfn_t end (i.e. start == end) since end is inclusive. However, pci_check_bar() > currently returns false in this case, which results in Xen not mapping the BAR > in the guest 2nd stage page tables. In this example boot log, Linux has mapped > the BARs in the 1st stage, but since Xen did not map them in the 2nd stage, > Linux encounters a data abort and panics: > > [ 2.593300] pci 0000:00:00.0: BAR 0: assigned [mem 0x50008000-0x50008fff] > [ 2.593682] pci 0000:00:00.0: BAR 2: assigned [mem 0x50009000-0x50009fff] > [ 2.594066] pci 0000:00:00.0: BAR 4: assigned [mem 0x5000a000-0x5000afff] > ... > [ 2.810502] virtio-pci 0000:00:00.0: enabling device (0000 -> 0002) > (XEN) 0000:00:00.0: not mapping BAR [50008, 50008] invalid position > (XEN) 0000:00:00.0: not mapping BAR [50009, 50009] invalid position > (XEN) 0000:00:00.0: not mapping BAR [5000a, 5000a] invalid position > [ 2.817502] virtio-pci 0000:00:00.0: virtio_pci: leaving for legacy driver > [ 2.817853] virtio-pci 0000:00:00.0: enabling bus mastering > (XEN) arch/arm/traps.c:1992:d0v0 HSR=0x00000093010045 pc=0xffff8000089507d4 > gva=0xffff80000c46d012 gpa=0x00000050008012 > [ 2.818397] Unable to handle kernel ttbr address size fault at virtual > address ffff80000c46d012 > ... > > Adjust the end physical address e to account for the full page when converting > from mfn, at which point s and e cannot be equal, so drop the equality check > in > the condition. > > Note that adjusting e to account for the full page also increases the accuracy > of the subsequent is_bar_valid check. > > Fixes: cc80e2bab0d0 ("xen/pci: replace call to is_memory_hole to > pci_check_bar") > Signed-off-by: Stewart Hildebrand <[email protected]> > Reviewed-by: Roger Pau Monné <[email protected]>
I tested the patch on N1SDP board everything works. Reviewed-by: Rahul Singh <[email protected]> Tested-by: Rahul Singh <[email protected]> Regards, Rahul
