diff options
| author | Jordan Niethe <jniethe5@gmail.com> | 2019-12-06 14:17:22 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-26 00:11:37 +1100 |
| commit | 736bcdd3a9fc672af33fb83230ecd0570ec38ec6 (patch) | |
| tree | 46b27cba94fa34092b40826832ad1a41189d1b22 /arch/powerpc/kernel/dt_cpu_ftrs.c | |
| parent | 5649607a8d0b0e019a4db14aab3de1e16c3a2b4f (diff) | |
| download | linux-736bcdd3a9fc672af33fb83230ecd0570ec38ec6.tar.bz2 | |
powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2
Commit a25bd72badfa ("powerpc/mm/radix: Workaround prefetch issue with
KVM") introduced a number of workarounds as coming out of a guest with
the mmu enabled would make the cpu would start running in hypervisor
state with the PID value from the guest. The cpu will then start
prefetching for the hypervisor with that PID value.
In Power9 DD2.2 the cpu behaviour was modified to fix this. When
accessing Quadrant 0 in hypervisor mode with LPID != 0 prefetching will
not be performed. This means that we can get rid of the workarounds for
Power9 DD2.2 and later revisions. Add a new cpu feature
CPU_FTR_P9_RADIX_PREFETCH_BUG to indicate if the workarounds are needed.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191206031722.25781-1-jniethe5@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/dt_cpu_ftrs.c')
| -rw-r--r-- | arch/powerpc/kernel/dt_cpu_ftrs.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c index 180b3a5d1001..182b4047c1ef 100644 --- a/arch/powerpc/kernel/dt_cpu_ftrs.c +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c @@ -727,17 +727,20 @@ static __init void cpufeatures_cpu_quirks(void) /* * Not all quirks can be derived from the cpufeatures device tree. */ - if ((version & 0xffffefff) == 0x004e0200) - ; /* DD2.0 has no feature flag */ - else if ((version & 0xffffefff) == 0x004e0201) + if ((version & 0xffffefff) == 0x004e0200) { + /* DD2.0 has no feature flag */ + cur_cpu_spec->cpu_features |= CPU_FTR_P9_RADIX_PREFETCH_BUG; + } else if ((version & 0xffffefff) == 0x004e0201) { cur_cpu_spec->cpu_features |= CPU_FTR_POWER9_DD2_1; - else if ((version & 0xffffefff) == 0x004e0202) { + cur_cpu_spec->cpu_features |= CPU_FTR_P9_RADIX_PREFETCH_BUG; + } else if ((version & 0xffffefff) == 0x004e0202) { cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_HV_ASSIST; cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_XER_SO_BUG; cur_cpu_spec->cpu_features |= CPU_FTR_POWER9_DD2_1; - } else if ((version & 0xffff0000) == 0x004e0000) + } else if ((version & 0xffff0000) == 0x004e0000) { /* DD2.1 and up have DD2_1 */ cur_cpu_spec->cpu_features |= CPU_FTR_POWER9_DD2_1; + } if ((version & 0xffff0000) == 0x004e0000) { cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR); |