path: root/virt
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authorSuzuki K Poulose <suzuki.poulose@arm.com>2018-09-26 17:32:52 +0100
committerMarc Zyngier <marc.zyngier@arm.com>2018-10-03 11:44:55 +0100
commit0f62f0e95be29200ab2ab98ca870e22c9b148dfa (patch)
tree7fb757498387a21b463eb6d35265aef89fe5b900 /virt
parentbc1d7de8c550db2f8fd59458a07fefa863358b8d (diff)
kvm: arm64: Set a limit on the IPA size
So far we have restricted the IPA size of the VM to the default value (40bits). Now that we can manage the IPA size per VM and support dynamic stage2 page tables, we can allow VMs to have larger IPA. This patch introduces a the maximum IPA size supported on the host. This is decided by the following factors : 1) Maximum PARange supported by the CPUs - This can be inferred from the system wide safe value. 2) Maximum PA size supported by the host kernel (48 vs 52) 3) Number of levels in the host page table (as we base our stage2 tables on the host table helpers). Since the stage2 page table code is dependent on the stage1 page table, we always ensure that : Number of Levels at Stage1 >= Number of Levels at Stage2 So we limit the IPA to make sure that the above condition is satisfied. This will affect the following combinations of VA_BITS and IPA for different page sizes. Host configuration | Unsupported IPA ranges 39bit VA, 4K | [44, 48] 36bit VA, 16K | [41, 48] 42bit VA, 64K | [47, 52] Supporting the above combinations need independent stage2 page table manipulation code, which would need substantial changes. We could purse the solution independently and switch the page table code once we have it ready. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <cdall@kernel.org> 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 'virt')
1 files changed, 2 insertions, 0 deletions
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 43e716bc3f08..631f9a3ad99a 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1413,6 +1413,8 @@ static int init_common_resources(void)
kvm_vmid_bits = kvm_get_vmid_bits();
kvm_info("%d-bit VMID\n", kvm_vmid_bits);
+ kvm_set_ipa_limit();
return 0;