lkml.org 
[lkml]   [2022]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of error
    On Tue, Nov 22, 2022 at 04:06:25PM +0100, Thomas Gleixner wrote:
    > On Tue, Nov 22 2022 at 10:20, Peter Zijlstra wrote:
    >
    > > On Mon, Nov 21, 2022 at 01:26:28PM +1300, Kai Huang wrote:
    > >
    > >> Shutting down the TDX module requires calling TDH.SYS.LP.SHUTDOWN on all
    > >> BIOS-enabled CPUs, and the SEMACALL can run concurrently on different
    > >> CPUs. Implement a mechanism to run SEAMCALL concurrently on all online
    > >> CPUs and use it to shut down the module. Later logical-cpu scope module
    > >> initialization will use it too.
    > >
    > > Uhh, those requirements ^ are not met by this:
    >
    > Can run concurrently != Must run concurrently
    >
    > The documentation clearly says "can run concurrently" as quoted above.

    The next sentense says: "Implement a mechanism to run SEAMCALL
    concurrently" -- it does not.

    Anyway, since we're all in agreement there is no such requirement at
    all, a schedule_on_each_cpu() might be more appropriate, there is no
    reason to use IPIs and spin-waiting for any of this.

    That said; perhaps we should grow:

    schedule_on_cpu(struct cpumask *cpus, work_func_t func);

    to only disturb a given mask of CPUs.

    \
     
     \ /
      Last update: 2022-11-22 20:08    [W:4.150 / U:0.172 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site