From: Daniel Henrique Barboza <danielhb413@gmail.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: aneesh.kumar@linux.ibm.com, qemu-ppc@nongnu.org,
qemu-devel@nongnu.org, groug@kaod.org
Subject: Re: [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT
Date: Tue, 15 Jun 2021 17:26:29 -0300 [thread overview]
Message-ID: <65a744dc-3edd-a0e8-4e32-dab7ad1d64d5@gmail.com> (raw)
In-Reply-To: <YMgmPDrr7oJFGME1@yekko>
On 6/15/21 1:02 AM, David Gibson wrote:
> 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.
Ok.
>
> 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.
I don't mind making it dependent on the default machine. I'll wrap this
CAS change (and as result, all FORM2 support) to be available only for
the default machine type.
Thanks,
Daniel
>
>> ---
>> 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);
>> }
>>
>
next prev parent reply other threads:[~2021-06-15 20:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 1:33 [RFC PATCH 0/8] pSeries base FORM2 NUMA affinity support Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 1/8] spapr: move NUMA data init to do_client_architecture_support() Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 2/8] spapr_numa.c: split FORM1 code into helpers Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 3/8] spapr_numa.c: wait for CAS before writing rtas DT Daniel Henrique Barboza
2021-06-15 4:02 ` David Gibson
2021-06-15 20:26 ` Daniel Henrique Barboza [this message]
2021-06-15 1:33 ` [RFC PATCH 4/8] spapr_numa.c: base FORM2 NUMA affinity support Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 5/8] spapr: simplify spapr_numa_associativity_init params Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 6/8] nvdimm: add PPC64 'device-node' property Daniel Henrique Barboza
2021-06-15 9:33 ` Aneesh Kumar K.V
2021-06-15 20:13 ` Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 7/8] spapr_numa, spapar_nvdimm: write secondary NUMA domain for nvdimms Daniel Henrique Barboza
2021-06-15 1:33 ` [RFC PATCH 8/8] spapr: move memory/cpu less check to spapr_numa_FORM1_affinity_init() Daniel Henrique Barboza
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