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Re: [PATCH v6 06/18] spapr, ppc: Remove VPM0/RMLS hacks for POWER9
From: |
David Gibson |
Subject: |
Re: [PATCH v6 06/18] spapr, ppc: Remove VPM0/RMLS hacks for POWER9 |
Date: |
Wed, 26 Feb 2020 12:00:41 +1100 |
On Tue, Feb 25, 2020 at 04:58:01PM +0100, Greg Kurz wrote:
> On Tue, 25 Feb 2020 12:29:00 +0100
> Greg Kurz <address@hidden> wrote:
>
> > On Tue, 25 Feb 2020 10:37:12 +1100
> > David Gibson <address@hidden> wrote:
> >
> > > For the "pseries" machine, we use "virtual hypervisor" mode where we
> > > only model the CPU in non-hypervisor privileged mode. This means that
> > > we need guest physical addresses within the modelled cpu to be treated
> > > as absolute physical addresses.
> > >
> > > We used to do that by clearing LPCR[VPM0] and setting LPCR[RMLS] to a high
> > > limit so that the old offset based translation for guest mode applied,
> > > which does what we need. However, POWER9 has removed support for that
> > > translation mode, which meant we had some ugly hacks to keep it working.
> > >
> > > We now explicitly handle this sort of translation for virtual hypervisor
> > > mode, so the hacks aren't necessary. We don't need to set VPM0 and RMLS
> > > from the machine type code - they're now ignored in vhyp mode. On the cpu
> > > side we don't need to allow LPCR[RMLS] to be set on POWER9 in vhyp mode -
> > > that was only there to allow the hack on the machine side.
> > >
> > > Signed-off-by: David Gibson <address@hidden>
> > > Reviewed-by: Cédric Le Goater <address@hidden>
> > > ---
> >
> > Reviewed-by: Greg Kurz <address@hidden>
> >
>
> Ah wait...
>
> > > hw/ppc/spapr_cpu_core.c | 6 +-----
> > > target/ppc/mmu-hash64.c | 8 --------
> > > 2 files changed, 1 insertion(+), 13 deletions(-)
> > >
> > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > > index d09125d9af..ea5e11f1d9 100644
> > > --- a/hw/ppc/spapr_cpu_core.c
> > > +++ b/hw/ppc/spapr_cpu_core.c
> > > @@ -58,14 +58,10 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu)
> > > * we don't get spurious wakups before an RTAS start-cpu call.
> > > * For the same reason, set PSSCR_EC.
> > > */
> > > - lpcr &= ~(LPCR_VPM0 | LPCR_VPM1 | LPCR_ISL | LPCR_KBV |
> > > pcc->lpcr_pm);
> > > + lpcr &= ~(LPCR_VPM1 | LPCR_ISL | LPCR_KBV | pcc->lpcr_pm);
>
> ... a few lines above, we have a comment that should be dropped as well.
>
> * Clearing VPM0 will also cause us to use RMOR in mmu-hash64.c for
> * real mode accesses, which thankfully defaults to 0 and isn't
> * accessible in guest mode.
Removed, thanks.
>
> My R-b tag stands anyway.
>
> > > lpcr |= LPCR_LPES0 | LPCR_LPES1;
> > > env->spr[SPR_PSSCR] |= PSSCR_EC;
> > >
> > > - /* Set RMLS to the max (ie, 16G) */
> > > - lpcr &= ~LPCR_RMLS;
> > > - lpcr |= 1ull << LPCR_RMLS_SHIFT;
> > > -
> > > ppc_store_lpcr(cpu, lpcr);
> > >
> > > /* Set a full AMOR so guest can use the AMR as it sees fit */
> > > diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
> > > index e372c42add..caf47ad6fc 100644
> > > --- a/target/ppc/mmu-hash64.c
> > > +++ b/target/ppc/mmu-hash64.c
> > > @@ -1126,14 +1126,6 @@ void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong
> > > val)
> > > (LPCR_PECE_L_MASK & (LPCR_PDEE | LPCR_HDEE |
> > > LPCR_EEE |
> > > LPCR_DEE | LPCR_OEE)) | LPCR_MER | LPCR_GTSE |
> > > LPCR_TC |
> > > LPCR_HEIC | LPCR_LPES0 | LPCR_HVICE | LPCR_HDICE);
> > > - /*
> > > - * If we have a virtual hypervisor, we need to bring back RMLS.
> > > It
> > > - * doesn't exist on an actual P9 but that's all we know how to
> > > - * configure with softmmu at the moment
> > > - */
> > > - if (cpu->vhyp) {
> > > - lpcr |= (val & LPCR_RMLS);
> > > - }
> > > break;
> > > default:
> > > g_assert_not_reached();
> >
> >
>
--
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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- [PATCH v6 02/18] ppc: Remove stub support for 32-bit hypervisor mode, (continued)
- [PATCH v6 04/18] target/ppc: Correct handling of real mode accesses with vhyp on hash MMU, David Gibson, 2020/02/24
- [PATCH v6 08/18] target/ppc: Use class fields to simplify LPCR masking, David Gibson, 2020/02/24
- [PATCH v6 10/18] target/ppc: Correct RMLS table, David Gibson, 2020/02/24
- [PATCH v6 13/18] spapr: Don't use weird units for MIN_RMA_SLOF, David Gibson, 2020/02/24
- [PATCH v6 12/18] target/ppc: Don't store VRMA SLBE persistently, David Gibson, 2020/02/24