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Re: [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT
From: |
David Gibson |
Subject: |
Re: [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT |
Date: |
Tue, 15 Jun 2021 14:02:04 +1000 |
On Mon, Jun 14, 2021 at 10:33:04PM -0300, Daniel Henrique Barboza wrote:
> spapr_numa_write_rtas_dt() is called from spapr_dt_rtas(), which in
> turned is called by spapr_build_fdt(). spapr_build_fdt() is called in
> two places: spapr_machine_reset() and do_client_architecture_support().
> When called in machine_reset() we're writing RTAS nodes with NUMA
> artifacts without going through CAS first.
>
> This is not an issue because we always write the same thing in DT, since
> we support just FORM1 NUMA affinity. With the upcoming FORM2 support,
> we're now reliant on guest choice to decide what to write.
>
> Instead of taking a guess (e.g. default to FORM1, switch to FORM2 if
> guest chooses it), postpone the writing of
> ibm,associativity-reference-points and ibm,max-associativity-domains
> until we're sure what was negotiated with the guest.
>
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
I think it makes sense to fold this in with 1/8 moving the calculation
itself until after CAS.
This does make a (theoretical) functional change - it means that NUMA
information is not available before CAS, which it was before. I think
that's very unlikely to break anything, but I wonder if we should make
it dependent on the machine version just to be safe.
> ---
> hw/ppc/spapr_numa.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/hw/ppc/spapr_numa.c b/hw/ppc/spapr_numa.c
> index 04a86f9b5b..e1a7f80076 100644
> --- a/hw/ppc/spapr_numa.c
> +++ b/hw/ppc/spapr_numa.c
> @@ -379,6 +379,10 @@ static void
> spapr_numa_FORM1_write_rtas_dt(SpaprMachineState *spapr,
> */
> void spapr_numa_write_rtas_dt(SpaprMachineState *spapr, void *fdt, int rtas)
> {
> + if (spapr_ovec_empty(spapr->ov5_cas)) {
> + return;
> + }
> +
> spapr_numa_FORM1_write_rtas_dt(spapr, fdt, rtas);
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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- [RFC PATCH 0/8] pSeries base FORM2 NUMA affinity support, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 1/8] spapr: move NUMA data init to do_client_architecture_support(), Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 2/8] spapr_numa.c: split FORM1 code into helpers, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT, Daniel Henrique Barboza, 2021/06/14
- Re: [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT,
David Gibson <=
- [RFC PATCH 4/8] spapr_numa.c: base FORM2 NUMA affinity support, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 5/8] spapr: simplify spapr_numa_associativity_init params, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 6/8] nvdimm: add PPC64 'device-node' property, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 7/8] spapr_numa, spapar_nvdimm: write secondary NUMA domain for nvdimms, Daniel Henrique Barboza, 2021/06/14
- [RFC PATCH 8/8] spapr: move memory/cpu less check to spapr_numa_FORM1_affinity_init(), Daniel Henrique Barboza, 2021/06/14