On 03/02/2015 10:15 PM, Michael Ellerman wrote: > On Mon, 2015-03-02 at 13:30 -0800, Tyrel Datwyler wrote: >> On 03/01/2015 08:19 PM, Cyril Bur wrote: >>> On Fri, 2015-02-27 at 18:24 -0800, Tyrel Datwyler wrote: >>>> During suspend/migration operation we must wait for the VASI state reported >>>> by the hypervisor to become Suspending prior to making the ibm,suspend-me >>>> RTAS call. Calling routines to rtas_ibm_supend_me() pass a vasi_state >>>> variable >>>> that exposes the VASI state to the caller. This is unnecessary as the >>>> caller >>>> only really cares about the following three conditions; if there is an >>>> error >>>> we should bailout, success indicating we have suspended and woken back up >>>> so >>>> proceed to device tree updated, or we are not suspendable yet so try >>>> calling >>>> rtas_ibm_suspend_me again shortly. >>>> >>>> This patch removes the extraneous vasi_state variable and simply uses the >>>> return code to communicate how to proceed. We either succeed, fail, or get >>>> -EAGAIN in which case we sleep for a second before trying to call >>>> rtas_ibm_suspend_me again. >>>> >>>> u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32) >>>> | be32_to_cpu(args.args[1]); >>>> - rc = rtas_ibm_suspend_me(handle, &vasi_rc); >>>> - args.rets[0] = cpu_to_be32(vasi_rc); >>>> - if (rc) >>>> + rc = rtas_ibm_suspend_me(handle); >>>> + if (rc == -EAGAIN) >>>> + args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE); >>> >>> (continuing on...) so perhaps here have >>> rc = 0; >>> else if (rc == -EIO) >>> args.rets[0] = cpu_to_be32(-1); >>> rc = 0; >>> Which should keep the original behaviour, the last thing we want to do >>> is break BE. >> >> The biggest problem here is we are making what basically equates to a >> fake rtas call from drmgr which we intercept in ppc_rtas(). From there >> we make this special call to rtas_ibm_suspend_me() to check VASI state >> and do a bunch of other specialized work that needs to be setup prior to >> making the actual ibm,suspend-me rtas call. Since, we are cheating PAPR >> here I guess we can really handle it however we want. I chose to simply >> fail the rtas call in the case where rtas_ibm_suspend_me() fails with >> something other than -EAGAIN. In user space librtas will log errno for >> the failure and return RTAS_IO_ASSERT to drmgr which in turn will log >> that error and fail. > > We don't want to change the return values of the syscall unless we absolutely > have to. And I don't think that's the case here.
I'd like to argue that the one case I changed makes sense, but its just as easy to keep the original behavior. > > Sure we think drmgr is the only thing that uses this crap, but we don't know > for sure. I can't imagine how anybody else could possibly use this hack without a streamid from the hmc/hypervisor, but I've been wrong in the past more times than I can count. :) -Tyrel > > cheers > > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev