On Wed, Feb 25, 2026 at 09:57:38PM -0500, Stewart Hildebrand wrote:
> A hotplugged PCI device may be added uninitialized. In particular,
> memory decoding might be disabled and the BARs might be zeroed. In this
> case, the BARs will not be mapped in p2m. However, vpci_make_msix_hole()
> unconditionally attempts to punch holes in p2m, leading to init_msix()
> failing:
>
> (XEN) d0v0 0000:01:00.0: existing mapping (mfn: 1c1880 type: 0) at 0 clobbers
> MSIX MMIO area
> (XEN) d0 0000:01:00.0: init legacy cap 17 fail rc=-17, mask it
>
> vpci_make_msix_hole() should only attempt to punch holes if the BARs
> containing the MSI-X/PBA tables are mapped in p2m. Introduce a helper
> for checking if a BAR is enabled, and add a check for the situation
> inside vpci_make_msix_hole().
>
> As a result of the newly introduced checks in vpci_make_msix_hole(),
> move the call to vpci_make_msix_hole() within modify_decoding() to after
> setting ->enabled.
>
> Fixes: ee2eb6849d50 ("vpci: Refactor REGISTER_VPCI_INIT")
> Signed-off-by: Stewart Hildebrand <[email protected]>
Reviewed-by: Roger Pau Monné <[email protected]>
Thanks.
