This is a note to let you know that I've just added the patch titled KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-arm64-restrict-ipa-size-to-maximum-48-bits-on-4k.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 95bc7194ef5dcc16563cc418c11e903721ea709a Author: Anshuman Khandual <anshuman.khandual@xxxxxxx> Date: Wed Aug 11 16:41:15 2021 +0530 KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size [ Upstream commit 5e5df9571c319fb107d7a523cc96fcc99961ee70 ] 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 <maz@xxxxxxxxxx> Cc: James Morse <james.morse@xxxxxxx> Cc: Alexandru Elisei <alexandru.elisei@xxxxxxx> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Fixes: c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration") Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> Link: https://lore.kernel.org/r/1628680275-16578-1-git-send-email-anshuman.khandual@xxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index b969c2157ad2..6058a80ec9ec 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -366,6 +366,14 @@ 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