On Fri, Jan 27, 2023 at 10:39:28PM -0500, Chuck Zmudzinski wrote: > On 1/27/2023 8:28 AM, Michael S. Tsirkin wrote: > > On Sun, Jan 15, 2023 at 07:49:51PM -0500, Chuck Zmudzinski wrote: > > > The current reserved slot check in do_pci_register_device(), added with > > > commit 8b8849844fd6 > > > > add ("subject here") please > > > > > ,is done even if the pci device being added is > > > configured manually for a particular slot. The new property, when set > > > to false, disables the check when the device is configured to request a > > > particular slot. This allows an administrator or management tool to > > > override slot_reserved_mask for a pci device by requesting a particular > > > slot for the device. The new property is initialized to true which > > > preserves the existing behavior of slot_reserved_mask by default. > > > > > > Signed-off-by: Chuck Zmudzinski <brchu...@aol.com> > > > > Thanks! > > I'm trying to think of the best default for this. > > I think it would be better for the default value of > enforce_slot_reserved_mask_manual to be false, so that a > user-specified slot will by default override slot_reserved_mask. > But doing that would change the current behavior of > slot_reserved_mask. > > Currently, this is the only place where slot_reserved_mask is used in all > of the Qemu source (code from hw/sparc64/sun4u.c): > > ------ snip ------- > /* Only in-built Simba APBs can exist on the root bus, slot 0 on busA is > reserved (leaving no slots free after on-board devices) however slots > 0-3 are free on busB */ > pci_bus->slot_reserved_mask = 0xfffffffc; > pci_busA->slot_reserved_mask = 0xfffffff1; > pci_busB->slot_reserved_mask = 0xfffffff0; > ------ snip ------- > > I think we could safely change the default value of > enforce_slot_reserved_mask_manual to false but set > it to true for the sparc64 sun4u board here to preserve > the current behavior of the only existing board in Qemu > that uses slot_reserved_mask. > > What do you think?
I guess first can you answer whether this is still needed with the latest Xen patches? -- MST