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
