diff options
Diffstat (limited to 'arch/arm64/kernel/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 7437b8c19528..b3202a99e559 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -268,6 +268,24 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = { static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = { /* + * Page size not being supported at Stage-2 is not fatal. You + * just give up KVM if PAGE_SIZE isn't supported there. Go fix + * your favourite nesting hypervisor. + * + * There is a small corner case where the hypervisor explicitly + * advertises a given granule size at Stage-2 (value 2) on some + * vCPUs, and uses the fallback to Stage-1 (value 0) for other + * vCPUs. Although this is not forbidden by the architecture, it + * indicates that the hypervisor is being silly (or buggy). + * + * We make no effort to cope with this and pretend that if these + * fields are inconsistent across vCPUs, then it isn't worth + * trying to bring KVM up. + */ + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN4_2_SHIFT, 4, 1), + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN64_2_SHIFT, 4, 1), + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN16_2_SHIFT, 4, 1), + /* * We already refuse to boot CPUs that don't support our configured * page size, so we can only detect mismatches for a page size other * than the one we're currently using. Unfortunately, SoCs like this |