On 2020/1/10 20:11, Lorenzo Pieralisi wrote: > On Mon, Dec 30, 2019 at 08:27:04PM +0800, Hanjun Guo wrote: >> The IORT spec [0] says Number of IDs = The number of IDs in the range minus >> one, it is confusing but it was written down in the first version of the >> IORT spec. But the IORT ID mapping function iort_id_map() did something >> wrong from the start, which bails out if: >> >> the request ID >= the input base + number of IDs >> >> This is wrong because it ignored the "minus one", and breaks some valid >> usecases such as ID mapping to contain single device mapping without >> single mapping flag set. >> >> Pankaj Bansal proposed a solution to fix the issue [1], which bails >> out if: >> >> the request ID > the input base + number of IDs >> >> This works as the spec defined, unfortunately some firmware didn't >> minus one for the number of IDs in the range, and the propoased >> solution will break those systems in this way: >> >> PCI hostbridge mapping entry 1: >> Input base: 0x1000 >> ID Count: 0x100 >> Output base: 0x1000 >> Output reference: 0xC4 //ITS reference >> >> PCI hostbridge mapping entry 2: >> Input base: 0x1100 >> ID Count: 0x100 >> Output base: 0x2000 >> Output reference: 0xD4 //ITS reference >> >> Two mapping entries which the second entry's Input base = the first >> entry's Input base + ID count, so for requester ID 0x1100 will map >> to ITS 0xC4 not 0xD4 if we update '>=' to '>'. >> >> So introduce a workaround to match the IORT's OEM information for >> the broken firmware, also update the logic of the ID mapping for >> firmwares report the number of IDs as the IORT spec defined, to >> make the code compatible for both kinds of system. >> >> I checked the ACPI tables in the tianocore/edk2-platforms [2], only >> HiSilicon HIP07/08 did wrong, so just add HIP07/08 to the workaround >> info table, if we break other platforms, we can add that later. >> >> [0]: http://infocenter.arm.com/help/topic/com.arm.doc.den0049d/DEN0049D_IO_Remapping_Table.pdf >> [1]: https://patchwork.kernel.org/patch/11292823/ >> [2]: https://github.com/tianocore/edk2-platforms >> >> Cc: Pankaj Bansal <pankaj.bansal@xxxxxxx> >> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> >> Signed-off-by: Hanjun Guo <guohanjun@xxxxxxxxxx> > > Commit log rewritten below - please update the code (and check the > log) as per this thread discussion. Thank you, I will resend it ASAP. Thanks Hanjun
