Even though ID_AA64MMFR0.PARANGE reports 52 bit PA size support, it cannot be enabled as guest IPA size on 4K or 16K page size configurations. Hence kvm_ipa_limit must be restricted to 48 bits. This change achieves required IPA capping.
Before the commit c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration"), the problem here would have been just latent via PHYS_MASK_SHIFT (which earlier in turn capped kvm_ipa_limit), which remains capped at 48 bits on 4K and 16K configs. Cc: Marc Zyngier <m...@kernel.org> Cc: James Morse <james.mo...@arm.com> Cc: Alexandru Elisei <alexandru.eli...@arm.com> Cc: Suzuki K Poulose <suzuki.poul...@arm.com> Cc: Catalin Marinas <catalin.mari...@arm.com> Cc: Will Deacon <w...@kernel.org> Cc: linux-arm-ker...@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Cc: linux-ker...@vger.kernel.org Fixes: c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration") Signed-off-by: Anshuman Khandual <anshuman.khand...@arm.com> --- This applies on v5.14-rc5 Changes in V2: - Replaced IS_ENABLED() based check with PAGE_SIZE based one per Marc - Moved the conditional code block near parange assignment per Marc Changes in V1: https://lore.kernel.org/lkml/1628657549-27584-1-git-send-email-anshuman.khand...@arm.com/ arch/arm64/kvm/reset.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index cba7872..78d4bd8 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -317,6 +317,14 @@ int kvm_set_ipa_limit(void) mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); parange = cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_PARANGE_SHIFT); + /* + * IPA size beyond 48 bits could not be supported + * on either 4K or 16K page size. Hence let's cap + * it to 48 bits, in case it's reported as larger + * on the system. + */ + if (PAGE_SIZE != SZ_64K) + parange = min(parange, (unsigned int)ID_AA64MMFR0_PARANGE_48); /* * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at -- 2.7.4 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm