From: Chris Browy <cbrowy@avery-design.com> To: Jonathan Cameron <jonathan.cameron@huawei.com> Cc: "20210212162442.00007c1d@huawei.com" <20210212162442.00007c1d@Huawei.com>, armbru@redhat.com, Ben Widawsky <ben.widawsky@intel.com>, dan.j.williams@intel.com, david@redhat.com, f4bug@amsat.org, imammedo@redhat.com, ira.weiny@intel.com, jgroves@micron.com, linux-cxl@vger.kernel.org, mst@redhat.com, qemu-devel@nongnu.org, vishal.l.verma@intel.com Subject: Re: [RFC PATCH v2 1/2] Basic PCIe DOE support Date: Thu, 18 Feb 2021 19:46:54 -0500 [thread overview] Message-ID: <DDBDE314-FA91-4E43-9484-F83E446B6EE4@avery-design.com> (raw) In-Reply-To: <20210218191143.00000cdf@Huawei.com> > On Feb 18, 2021, at 2:11 PM, Jonathan Cameron <jonathan.cameron@huawei.com> wrote: > > On Fri, 12 Feb 2021 16:58:21 -0500 > Chris Browy <cbrowy@avery-design.com> wrote: > >>> On Feb 12, 2021, at 11:24 AM, Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: >>> >>> On Tue, 9 Feb 2021 15:35:49 -0500 >>> Chris Browy <cbrowy@avery-design.com> wrote: >>> >>> Run ./scripts/checkpatch.pl over the patches and fix all the warnings before >>> posting. It will save time by clearing out most of the minor formatting issues >>> and similar that inevitably sneak in during development. >>> >> Excellent suggestion. We’re still newbies! >> >>> The biggest issue I'm seeing in here is that the abstraction of >>> multiple DOE capabiltiies accessing same protocols doesn't make sense. >>> >>> Each DOE ecap region and hence mailbox can have it's own set of >>> (possibly overlapping) protocols. >>> >>> From the ECN: >>> "It is permitted for a protocol using data object exchanges to require >>> that a Function implement a unique instance of DOE for that specific >>> protocol, and/or to allow sharing of a DOE instance to only a specific >>> set of protocols using data object exchange, and/or to allow a Function >>> to implement multiple instances of DOE supporting the specific protocol." >>> >>> Tightly couple the ECAP and DOE. If we are in the multiple instances >>> of DOE supporting a specific protocol case, then register it separately >>> for each one. The individual device emulation then needs to deal with >>> any possible clashes etc. >> >> Not sure how configurable we want to make the device. It is a simple type 3 >> device after all. > > Agreed, but what I (or someone else) really doesn't want to have to do > in the future is reimplement DOE because we made design decisions that make > this version hard to reuse. Unless it is particularly nasty to do we should > try to design something that is generally useful rather than targeted to > closely at the specific case we are dealing with. > > I'd argue the ECAP and the DOE mailbox are always tightly coupled 1-to-1. > Whether the device wants to implement multiple protocols on each DOE mailbox > or indeed run individual protocols on multiple DOE mailboxes is a design > decision, but the actual mechanics of DOE match up with the config > space structures anything else is impdef on the device. Yes I agree that there is 1-to-1 between DOE extended cap (ECAP) and DOE Mailbox. If we want to provide complete flexibility we should let the user pass device property arrays to QEMU command for how many DOE ECAP’s to build out and how to assign protocol(s) to each of them. Array index is the DOE instance #. Also we can provide a property for cdat binary (blob) filename to initialize the CDAT structure[entries]. This just reads in whatever mix of CDAT structure types are in the blob. -device cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0,size=256M \ doe-ecap-instances=2 \ doe-ecap[0]=5 // bitwise OR for protocols shared doe-ecap[1]=2 //bitwise OR for protocols shared doe-ecap-cdat[1]=mycdat.bin where let’s say protocols bitvector bit [0]=CMA bit [1]=CDAT bit [2}=Compliance Let me know if you some better alternatives and we’ll implement it. > >> >> The DOE spec does leave it pretty arbitrary regarding N DOE instances (DOE >> Extended Cap entry points) for M protocols, including where N>1 and M=1. >> Currently we implement N=2 DOE caps (instances), one for CDAT, one for >> Compliance Mode.[ >> >> Maybe a more complex MLD device might have one or more DOE instances >> for the CDAT protocol alone to define each HDM but currently we only have >> one pmem (SLD) so we can’t really do much more than what’s supported. >> >> Open to further suggestion though. Based on answer to above we’ll follow >> the suggestion lower in the code review regarding >> > ... >
WARNING: multiple messages have this Message-ID (diff)
From: Chris Browy <cbrowy@avery-design.com> To: Jonathan Cameron <jonathan.cameron@huawei.com> Cc: Ben Widawsky <ben.widawsky@intel.com>, david@redhat.com, qemu-devel@nongnu.org, vishal.l.verma@intel.com, jgroves@micron.com, armbru@redhat.com, linux-cxl@vger.kernel.org, f4bug@amsat.org, "20210212162442.00007c1d@huawei.com" <20210212162442.00007c1d@Huawei.com>, mst@redhat.com, imammedo@redhat.com, dan.j.williams@intel.com, ira.weiny@intel.com Subject: Re: [RFC PATCH v2 1/2] Basic PCIe DOE support Date: Thu, 18 Feb 2021 19:46:54 -0500 [thread overview] Message-ID: <DDBDE314-FA91-4E43-9484-F83E446B6EE4@avery-design.com> (raw) In-Reply-To: <20210218191143.00000cdf@Huawei.com> > On Feb 18, 2021, at 2:11 PM, Jonathan Cameron <jonathan.cameron@huawei.com> wrote: > > On Fri, 12 Feb 2021 16:58:21 -0500 > Chris Browy <cbrowy@avery-design.com> wrote: > >>> On Feb 12, 2021, at 11:24 AM, Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: >>> >>> On Tue, 9 Feb 2021 15:35:49 -0500 >>> Chris Browy <cbrowy@avery-design.com> wrote: >>> >>> Run ./scripts/checkpatch.pl over the patches and fix all the warnings before >>> posting. It will save time by clearing out most of the minor formatting issues >>> and similar that inevitably sneak in during development. >>> >> Excellent suggestion. We’re still newbies! >> >>> The biggest issue I'm seeing in here is that the abstraction of >>> multiple DOE capabiltiies accessing same protocols doesn't make sense. >>> >>> Each DOE ecap region and hence mailbox can have it's own set of >>> (possibly overlapping) protocols. >>> >>> From the ECN: >>> "It is permitted for a protocol using data object exchanges to require >>> that a Function implement a unique instance of DOE for that specific >>> protocol, and/or to allow sharing of a DOE instance to only a specific >>> set of protocols using data object exchange, and/or to allow a Function >>> to implement multiple instances of DOE supporting the specific protocol." >>> >>> Tightly couple the ECAP and DOE. If we are in the multiple instances >>> of DOE supporting a specific protocol case, then register it separately >>> for each one. The individual device emulation then needs to deal with >>> any possible clashes etc. >> >> Not sure how configurable we want to make the device. It is a simple type 3 >> device after all. > > Agreed, but what I (or someone else) really doesn't want to have to do > in the future is reimplement DOE because we made design decisions that make > this version hard to reuse. Unless it is particularly nasty to do we should > try to design something that is generally useful rather than targeted to > closely at the specific case we are dealing with. > > I'd argue the ECAP and the DOE mailbox are always tightly coupled 1-to-1. > Whether the device wants to implement multiple protocols on each DOE mailbox > or indeed run individual protocols on multiple DOE mailboxes is a design > decision, but the actual mechanics of DOE match up with the config > space structures anything else is impdef on the device. Yes I agree that there is 1-to-1 between DOE extended cap (ECAP) and DOE Mailbox. If we want to provide complete flexibility we should let the user pass device property arrays to QEMU command for how many DOE ECAP’s to build out and how to assign protocol(s) to each of them. Array index is the DOE instance #. Also we can provide a property for cdat binary (blob) filename to initialize the CDAT structure[entries]. This just reads in whatever mix of CDAT structure types are in the blob. -device cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0,size=256M \ doe-ecap-instances=2 \ doe-ecap[0]=5 // bitwise OR for protocols shared doe-ecap[1]=2 //bitwise OR for protocols shared doe-ecap-cdat[1]=mycdat.bin where let’s say protocols bitvector bit [0]=CMA bit [1]=CDAT bit [2}=Compliance Let me know if you some better alternatives and we’ll implement it. > >> >> The DOE spec does leave it pretty arbitrary regarding N DOE instances (DOE >> Extended Cap entry points) for M protocols, including where N>1 and M=1. >> Currently we implement N=2 DOE caps (instances), one for CDAT, one for >> Compliance Mode.[ >> >> Maybe a more complex MLD device might have one or more DOE instances >> for the CDAT protocol alone to define each HDM but currently we only have >> one pmem (SLD) so we can’t really do much more than what’s supported. >> >> Open to further suggestion though. Based on answer to above we’ll follow >> the suggestion lower in the code review regarding >> > ... >
next prev parent reply other threads:[~2021-02-19 0:50 UTC|newest] Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-09 19:59 [RFC PATCH v2 0/2] PCIe DOE for PCIe and CXL 2.0 v2 release Chris Browy 2021-02-09 20:35 ` [RFC PATCH v2 1/2] Basic PCIe DOE support Chris Browy 2021-02-09 21:42 ` Ben Widawsky 2021-02-09 21:42 ` Ben Widawsky 2021-02-09 22:10 ` Chris Browy 2021-02-09 22:10 ` Chris Browy 2021-02-12 16:24 ` Jonathan Cameron 2021-02-12 16:24 ` Jonathan Cameron 2021-02-12 21:58 ` Chris Browy 2021-02-12 21:58 ` Chris Browy 2021-02-18 19:11 ` Jonathan Cameron 2021-02-18 19:11 ` Jonathan Cameron 2021-02-19 0:46 ` Chris Browy [this message] 2021-02-19 0:46 ` Chris Browy 2021-02-19 12:33 ` Jonathan Cameron 2021-02-19 12:33 ` Jonathan Cameron 2021-03-04 19:21 ` Jonathan Cameron 2021-03-04 19:21 ` Jonathan Cameron 2021-03-04 19:50 ` Chris Browy 2021-03-04 19:50 ` Chris Browy 2021-02-09 20:36 ` [RFC v2 2/2] Basic CXL DOE for CDAT and Compliance Mode Chris Browy 2021-02-09 21:53 ` Ben Widawsky 2021-02-09 21:53 ` Ben Widawsky 2021-02-09 22:53 ` Chris Browy 2021-02-09 22:53 ` Chris Browy 2021-02-12 17:23 ` Jonathan Cameron 2021-02-12 17:23 ` Jonathan Cameron 2021-02-12 22:26 ` Chris Browy 2021-02-12 22:26 ` Chris Browy 2021-02-18 19:15 ` Jonathan Cameron 2021-02-18 19:15 ` Jonathan Cameron 2021-02-19 0:53 ` Chris Browy 2021-02-19 0:53 ` Chris Browy
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