adding Marcel; comments at the bottom On 08/07/18 09:20, Jing Liu wrote: > Add a device-specific capability for the RedHat PCI BRIDGE > to enable reserving additional resources. > > Signed-off-by: Jing Liu <[email protected]> > --- > src/fw/pciinit.c | 9 ++++++--- > src/hw/pci_ids.h | 1 + > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c > index 3a2f747..0265e9d 100644 > --- a/src/fw/pciinit.c > +++ b/src/fw/pciinit.c > @@ -525,9 +525,12 @@ static void pci_bios_init_platform(void) > > static u8 pci_find_resource_reserve_capability(u16 bdf) > { > - if (pci_config_readw(bdf, PCI_VENDOR_ID) == PCI_VENDOR_ID_REDHAT && > - pci_config_readw(bdf, PCI_DEVICE_ID) == > - PCI_DEVICE_ID_REDHAT_ROOT_PORT) { > + u16 vendor_id = pci_config_readw(bdf, PCI_VENDOR_ID); > + u16 device_id = pci_config_readw(bdf, PCI_DEVICE_ID); > + > + if (vendor_id == PCI_VENDOR_ID_REDHAT && > + (device_id == PCI_DEVICE_ID_REDHAT_ROOT_PORT || > + device_id == PCI_DEVICE_ID_REDHAT_BRIDGE)) { > u8 cap = 0; > do { > cap = pci_find_capability(bdf, PCI_CAP_ID_VNDR, cap); > diff --git a/src/hw/pci_ids.h b/src/hw/pci_ids.h > index 38fa2ca..1096461 100644 > --- a/src/hw/pci_ids.h > +++ b/src/hw/pci_ids.h > @@ -2265,6 +2265,7 @@ > > #define PCI_VENDOR_ID_REDHAT 0x1b36 > #define PCI_DEVICE_ID_REDHAT_ROOT_PORT 0x000C > +#define PCI_DEVICE_ID_REDHAT_BRIDGE 0x0001 > > #define PCI_VENDOR_ID_TEKRAM 0x1de1 > #define PCI_DEVICE_ID_TEKRAM_DC290 0xdc29 >
Given that you are touching this function, it's a good opportunity to clean up its issues that I pointed out earlier in <https://bugzilla.redhat.com/show_bug.cgi?id=1536147#c0>, noted as "side comments (a), (b) and (c)". I'll re-iterate: * The "PCI: QEMU resource reserve cap not found" debug message is printed under wrong conditions. Namely, it is both printed when it makes no sense (i.e., when the vendor-id/device-id don't match and we don't even go looking for the capability), and it's *not* printed when it does makes sense (the search loop completes without finding the capability). * There is a logic bug: if we find the capability but it's truncated, we print a good error message, but then go ahead and return the offset of the broken (truncated) capability just the same. In this case, we should return zero. So, I suggest that you please: (1) send a patch that fixes the logic bug, (2) send another patch that cleans up the debug messages, (3) send yet another patch that recognizes the capability in question on the traditional bridge device too. (I.e., a variant of the current patch, rebased to (1) and (2)). More comments for this patch: (4) the subject line should be clarified, such as: pci: recognize RH resource reservation capability on traditional bridges (72 characters). The commit message body should be updated accordingly -- we're not adding the capability, just matching it on another device. (5) Regarding the code: I'm not sure how careful SeaBIOS is about unnecessary config space accesses (i.e., unnecessary traps to the host). Personally I would prefer if we didn't unconditionally read the device ID post-patch either -- that is, if the vendor ID doesn't match, we shouldn't read the device ID. Something like: > u16 device_id; > > if (pci_config_readw(bdf, PCI_VENDOR_ID) != PCI_VENDOR_ID_REDHAT) { > return 0; > } > > device_id = pci_config_readw(bdf, PCI_DEVICE_ID); > if (device_id != PCI_DEVICE_ID_REDHAT_ROOT_PORT && > device_id != PCI_DEVICE_ID_REDHAT_BRIDGE) { > return 0; > } > > /* success / failure messages are justified after this point */ > ... The vendor-id/device-id checks should likely be reorganized as shown above in patch (2), as a part of the debug message cleanup. And then the device-id check can be extended to cover PCI_DEVICE_ID_REDHAT_BRIDGE in patch (3). Just my opinion of course; I'm not a SeaBIOS maintainer. Thanks, Laszlo _______________________________________________ SeaBIOS mailing list [email protected] https://mail.coreboot.org/mailman/listinfo/seabios
