-----"Jason Gunthorpe" <jgg@xxxxxxxx> wrote: ----- >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx> >From: "Jason Gunthorpe" <jgg@xxxxxxxx> >Date: 08/19/2019 05:07PM >Cc: "Geert Uytterhoeven" <geert@xxxxxxxxxxxxxx>, "Doug Ledford" ><dledford@xxxxxxxxxx>, linux-rdma@xxxxxxxxxxxxxxx, >linux-kernel@xxxxxxxxxxxxxxx >Subject: [EXTERNAL] Re: Re: Re: [PATCH] RDMA/siw: Fix compiler >warnings on 32-bit due to u64/pointer abuse > >On Mon, Aug 19, 2019 at 02:52:13PM +0000, Bernard Metzler wrote: >> >> >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx> >> >From: "Jason Gunthorpe" <jgg@xxxxxxxx> >> >Date: 08/19/2019 04:19PM >> >Cc: "Geert Uytterhoeven" <geert@xxxxxxxxxxxxxx>, "Doug Ledford" >> ><dledford@xxxxxxxxxx>, linux-rdma@xxxxxxxxxxxxxxx, >> >linux-kernel@xxxxxxxxxxxxxxx >> >Subject: [EXTERNAL] Re: Re: Re: [PATCH] RDMA/siw: Fix compiler >> >warnings on 32-bit due to u64/pointer abuse >> > >> >On Mon, Aug 19, 2019 at 02:15:36PM +0000, Bernard Metzler wrote: >> >> >> >> >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx> >> >> >From: "Jason Gunthorpe" <jgg@xxxxxxxx> >> >> >Date: 08/19/2019 03:52PM >> >> >Cc: "Geert Uytterhoeven" <geert@xxxxxxxxxxxxxx>, "Doug Ledford" >> >> ><dledford@xxxxxxxxxx>, linux-rdma@xxxxxxxxxxxxxxx, >> >> >linux-kernel@xxxxxxxxxxxxxxx >> >> >Subject: [EXTERNAL] Re: Re: [PATCH] RDMA/siw: Fix compiler >> >warnings >> >> >on 32-bit due to u64/pointer abuse >> >> > >> >> >On Mon, Aug 19, 2019 at 01:36:11PM +0000, Bernard Metzler >wrote: >> >> >> >If the value is really a kernel pointer, then it ought to be >> >> >printed >> >> >> >with %p. We have been getting demanding on this point lately >in >> >> >RDMA >> >> >> >to enforce the ability to keep kernel pointers secret. >> >> >> > >> >> >> >> - wqe->sqe.sge[0].laddr = (u64)&wqe->sqe.sge[1]; >> >> >> >> + wqe->sqe.sge[0].laddr = (uintptr_t)&wqe->sqe.sge[1]; >> >> >> > >> >> >> >[..] >> >> >> > >> >> >> >> rv = siw_rx_kva(srx, >> >> >> >> - (void *)(sge->laddr + frx->sge_off), >> >> >> >> + (void *)(uintptr_t)(sge->laddr + frx->sge_off), >> >> >> >> sge_bytes); >> >> >> > >> >> >> >Bernard, this is nonsense, what is going on here with >> >sge->laddr >> >> >that >> >> >> >it can't be a void *? >> >> >> > >> >> >> siw_sge is defined in siw-abi.h. We make the address u64 to >keep >> >> >the ABI >> >> >> arch independent. >> >> > >> >> >Eh? How does the siw-abi.h store a kernel pointer? Sounds like >> >kernel >> >> >and user types are being mixed. >> >> > >> >> >> >> siw-abi.h defines the work queue elements of a siw send queue. >> >> For user land, the send queue is mmapped. Kernel or user land >> >> clients write to its send queue when posting work >> >> (SGE: buffer address, length, local key). >> > >> >Should have different types.. Don't want to accidently mix a laddr >> >under user control with one under kernel control. >> > >> Well we have an unsigned 64bit for both user and kernel >> application buffer addresses throughout the rdma stack, > >We do not. Kernel addresses are consistenyly void * or dma_addr_t > Absolutely. But these addresses are conveyed through the API as unsigned 64 during post_send(), and land in the siw send queue as is. During send queue processing, these addresses must be interpreted according to its context and transformed (casted) back to the callers intention. I frankly do not know what we can do differently... The representation of all addresses as unsigned 64 is given. Sorry for the confusion. >Most places that consume a data address are using lkeys anyhow, which >does have a lkey & u64, but that u64 is not a application buffer >address, but the IOVA of the lkey, which is very different. > >I really have no idea why siw needs to mix kernel VAs with user >pointers, particularly in wqes... > >Jason > >