From: David Gibson <david@gibson.dropbear.id.au>
To: Greg Kurz <groug@kaod.org>
Cc: "Alexey Kardashevskiy" <aik@ozlabs.ru>,
qemu-ppc@nongnu.org, "Cédric Le Goater" <clg@kaod.org>,
qemu-devel@nongnu.org
Subject: Re: [PATCH 1/4] spapr: Don't check capabilities removed between CAS calls
Date: Thu, 26 Mar 2020 11:02:45 +1100 [thread overview]
Message-ID: <20200326000245.GH36889@umbus.fritz.box> (raw)
In-Reply-To: <158514993021.478799.10928618293640651819.stgit@bahia.lan>
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On Wed, Mar 25, 2020 at 04:25:30PM +0100, Greg Kurz wrote:
> We currently check if some capability in OV5 was removed by the guest
> since the previous CAS, and we trigger a CAS reboot in that case. This
> was required because it could call for a device-tree property or node
> removal, that we didn't support until recently (see commit 6787d27b04a7
> "spapr: add option vector handling in CAS-generated resets" for details).
>
> Now that we render a full FDT at CAS and that SLOF is able to handle
> node removal, we don't need to do a CAS reset in this case anymore.
> Also, this check can only return true if the guest has already called
> CAS since the last full system reset (otherwise spapr->ov5_cas is
> empty). Linux doesn't do that so this can be considered as dead code
> for the vast majority of existing setups.
>
> Drop the check. Since the only use of the ov5_cas_old variable is
> precisely the check itself, drop the variable as well.
>
> Signed-off-by: Greg Kurz <groug@kaod.org>
Applied to ppc-for-5.1.
> ---
> hw/ppc/spapr_hcall.c | 14 +-------------
> 1 file changed, 1 insertion(+), 13 deletions(-)
>
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 40c86e91eb89..1f123a68e46c 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -1676,7 +1676,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
> target_ulong fdt_bufsize = args[2];
> target_ulong ov_table;
> uint32_t cas_pvr;
> - SpaprOptionVector *ov1_guest, *ov5_guest, *ov5_cas_old;
> + SpaprOptionVector *ov1_guest, *ov5_guest;
> bool guest_radix;
> Error *local_err = NULL;
> bool raw_mode_supported = false;
> @@ -1781,22 +1781,10 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
> * by LoPAPR 1.1, 14.5.4.8, which QEMU doesn't implement, we don't need
> * to worry about this for now.
> */
> - ov5_cas_old = spapr_ovec_clone(spapr->ov5_cas);
> -
> - /* also clear the radix/hash bit from the current ov5_cas bits to
> - * be in sync with the newly ov5 bits. Else the radix bit will be
> - * seen as being removed and this will generate a reset loop
> - */
> - spapr_ovec_clear(ov5_cas_old, OV5_MMU_RADIX_300);
>
> /* full range of negotiated ov5 capabilities */
> spapr_ovec_intersect(spapr->ov5_cas, spapr->ov5, ov5_guest);
> spapr_ovec_cleanup(ov5_guest);
> - /* capabilities that have been added since CAS-generated guest reset.
> - * if capabilities have since been removed, generate another reset
> - */
> - spapr->cas_reboot = !spapr_ovec_subset(ov5_cas_old, spapr->ov5_cas);
> - spapr_ovec_cleanup(ov5_cas_old);
> /* Now that processing is finished, set the radix/hash bit for the
> * guest if it requested a valid mode; otherwise terminate the boot. */
> if (guest_radix) {
>
--
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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next prev parent reply other threads:[~2020-03-26 0:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 15:25 [PATCH 0/4] spapr: Get rid of CAS reboot flag Greg Kurz
2020-03-25 15:25 ` [PATCH 1/4] spapr: Don't check capabilities removed between CAS calls Greg Kurz
2020-03-26 0:02 ` David Gibson [this message]
2020-03-25 15:25 ` [PATCH 2/4] spapr: Simplify selection of radix/hash during CAS Greg Kurz
2020-03-25 15:25 ` [PATCH 3/4] spapr/cas: Separate CAS handling from rebuilding the FDT Greg Kurz
2020-03-25 15:25 ` [PATCH 4/4] spapr: Drop CAS reboot flag Greg Kurz
2020-03-31 0:44 ` [PATCH 0/4] spapr: Get rid of " David Gibson
2020-03-31 2:59 ` Alexey Kardashevskiy
2020-03-31 7:08 ` Greg Kurz
2020-03-31 10:29 ` Alexey Kardashevskiy
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