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KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size

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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 c9b69a0cf0 ("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 <[email protected]>
Cc: James Morse <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Fixes: c9b69a0cf0 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration")
Signed-off-by: Anshuman Khandual <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
This commit is contained in:
Anshuman Khandual authored and Marc Zyngier committed 2021-08-11 16:00:04 +01:00
1 parent b31578f627
commit 5e5df9571c
1 file changed
+8
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arch/arm64/kvm/reset.c
+8
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@@ -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