On 6/8/20 1:57 PM, Cédric Le Goater wrote: > POWER8 and POWER9 have 12-bit LPIDs. Change LPID_RSVD to support up to > (4096 - 2) guests on these processors. POWER7 is kept the same with a > limitation of (1024 - 2), but it might be time to drop KVM support for > POWER7. > > Tested with 2048 guests * 4 vCPUs on a witherspoon system with 512G > RAM and a bit of swap.
For the record, it is possible to run 4094 guests * 4 vCPUs on a POWER9 system with 1TB. It takes ~5m to boot them all. CONFIG_NR_IRQS needs to be increased to support 4094 * 4 escalation interrupts. Cheers, C. > > Signed-off-by: Cédric Le Goater <c...@kaod.org> > --- > arch/powerpc/include/asm/reg.h | 3 ++- > arch/powerpc/kvm/book3s_64_mmu_hv.c | 8 ++++++-- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h > index 88e6c78100d9..b70bbfb0ea3c 100644 > --- a/arch/powerpc/include/asm/reg.h > +++ b/arch/powerpc/include/asm/reg.h > @@ -473,7 +473,8 @@ > #ifndef SPRN_LPID > #define SPRN_LPID 0x13F /* Logical Partition Identifier */ > #endif > -#define LPID_RSVD 0x3ff /* Reserved LPID for partn switching */ > +#define LPID_RSVD_POWER7 0x3ff /* Reserved LPID for partn switching */ > +#define LPID_RSVD 0xfff /* Reserved LPID for partn switching */ > #define SPRN_HMER 0x150 /* Hypervisor maintenance exception reg > */ > #define HMER_DEBUG_TRIG (1ul << (63 - 17)) /* Debug trigger */ > #define SPRN_HMEER 0x151 /* Hyp maintenance exception enable reg > */ > diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c > b/arch/powerpc/kvm/book3s_64_mmu_hv.c > index 18aed9775a3c..23035ab2ec50 100644 > --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c > +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c > @@ -260,11 +260,15 @@ int kvmppc_mmu_hv_init(void) > if (!mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE)) > return -EINVAL; > > - /* POWER7 has 10-bit LPIDs (12-bit in POWER8) */ > host_lpid = 0; > if (cpu_has_feature(CPU_FTR_HVMODE)) > host_lpid = mfspr(SPRN_LPID); > - rsvd_lpid = LPID_RSVD; > + > + /* POWER8 and above have 12-bit LPIDs (10-bit in POWER7) */ > + if (cpu_has_feature(CPU_FTR_ARCH_207S)) > + rsvd_lpid = LPID_RSVD; > + else > + rsvd_lpid = LPID_RSVD_POWER7; > > kvmppc_init_lpid(rsvd_lpid + 1); > >
