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| author | Suzuki K Poulose <suzuki.poulose@arm.com> | 2018-09-26 17:32:54 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-10-03 11:45:20 +0100 |
| commit | 233a7cb235318223df8133235383f4c595c654c1 (patch) | |
| tree | 04f9ed017c9cf6463f7bcf95801b8e070da0b7ef /arch/arm64/kvm/reset.c | |
| parent | 58b3efc820acd3219e89ff014e93346a734229b8 (diff) | |
| download | linux-233a7cb235318223df8133235383f4c595c654c1.tar.gz | |
kvm: arm64: Allow tuning the physical address size for VM
Allow specifying the physical address size limit for a new VM via the kvm_type argument for the KVM_CREATE_VM ioctl. This allows us to finalise the stage2 page table as early as possible and hence perform the right checks on the memory slots without complication. The size is encoded as Log2(PA_Size) in bits[7:0] of the type field. For backward compatibility the value 0 is reserved and implies 40bits. Also, lift the limit of the IPA to host limit and allow lower IPA sizes (e.g, 32). The userspace could check the extension KVM_CAP_ARM_VM_IPA_SIZE for the availability of this feature. The cap check returns the maximum limit for the physical address shift supported by the host. Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <cdall@kernel.org> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kvm/reset.c')
| -rw-r--r-- | arch/arm64/kvm/reset.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index f156e45760bc..95f28d5950e0 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -89,6 +89,9 @@ int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_VCPU_EVENTS: r = 1; break; + case KVM_CAP_ARM_VM_IPA_SIZE: + r = kvm_ipa_limit; + break; default: r = 0; } @@ -192,17 +195,23 @@ int kvm_arm_config_vm(struct kvm *kvm, unsigned long type) u32 parange, phys_shift; u8 lvls; - if (type) + if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK) return -EINVAL; + phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); + if (phys_shift) { + if (phys_shift > kvm_ipa_limit || + phys_shift < 32) + return -EINVAL; + } else { + phys_shift = KVM_PHYS_SHIFT; + } + parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 7; if (parange > ID_AA64MMFR0_PARANGE_MAX) parange = ID_AA64MMFR0_PARANGE_MAX; vtcr |= parange << VTCR_EL2_PS_SHIFT; - phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange); - if (phys_shift > KVM_PHYS_SHIFT) - phys_shift = KVM_PHYS_SHIFT; vtcr |= VTCR_EL2_T0SZ(phys_shift); /* * Use a minimum 2 level page table to prevent splitting |