lkml.org 
[lkml]   [2019]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [RFC PATCH 0/2] Add support for SBI version to 0.2
    From
    On Sun, 15 Sep 2019 23:54:46 PDT (-0700), Christoph Hellwig wrote:
    > On Fri, Sep 13, 2019 at 08:54:27AM -0700, Palmer Dabbelt wrote:
    >> On Tue, Sep 3, 2019 at 12:38 AM hch@infradead.org <hch@infradead.org> wrote:
    >>
    >> > On Fri, Aug 30, 2019 at 11:13:25PM +0000, Atish Patra wrote:
    >> > > If I understood you clearly, you want to call it legacy in the spec and
    >> > > just say v0.1 extensions.
    >> > >
    >> > > The whole idea of marking them as legacy extensions to indicate that it
    >> > > would be obsolete in the future.
    >> > >
    >> > > But I am not too worried about the semantics here. So I am fine with
    >> > > just changing the text to v0.1 if that avoids confusion.
    >> >
    >> > So my main problems is that we are lumping all the "legacy" extensions
    >> > together. While some of them are simply a bad idea and shouldn't
    >> > really be implemented for anything new ever, others like the sfence.vma
    >> > and ipi ones are needed until we have hardware support to avoid them
    >> > and possibly forever for virtualization.
    >> >
    >> > So either we use different markers of legacy for them, or we at least
    >> > define new extensions that replace them at the same time. What I
    >> > want to avoid is the possibіly of an implementation using the really
    >> > legacy bits and new extensions at the same time.
    >> >
    >>
    >> Nominally we've got to replace these as well because we didn't include
    >> the length of the hart mask.
    >
    > Well, let's do that as part of definining the first real post-0.1
    > SBI then, and don't bother defining the old ones as legacy at all.
    >
    > Just two different specs that don't interact except that we reserve
    > extension space in the new one for the old one so that one SBI spec
    > can implement both.

    Makes sense. We're getting finish with this "just go write everything down"
    exercise, so we can start actually doing things now :).

    \
     
     \ /
      Last update: 2019-09-16 18:13    [W:3.419 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site