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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 /include/uapi/linux/kvm.h | |
| parent | kvm: arm64: Limit the minimum number of page table levels (diff) | |
| download | linux-dev-233a7cb235318223df8133235383f4c595c654c1.tar.xz linux-dev-233a7cb235318223df8133235383f4c595c654c1.zip | |
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 'include/uapi/linux/kvm.h')
| -rw-r--r-- | include/uapi/linux/kvm.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 251be353f950..95aa73ca65dc 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -751,6 +751,15 @@ struct kvm_ppc_resize_hpt { #define KVM_S390_SIE_PAGE_OFFSET 1 /* + * On arm64, machine type can be used to request the physical + * address size for the VM. Bits[7-0] are reserved for the guest + * PA size shift (i.e, log2(PA_Size)). For backward compatibility, + * value 0 implies the default IPA size, 40bits. + */ +#define KVM_VM_TYPE_ARM_IPA_SIZE_MASK 0xffULL +#define KVM_VM_TYPE_ARM_IPA_SIZE(x) \ + ((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK) +/* * ioctls for /dev/kvm fds: */ #define KVM_GET_API_VERSION _IO(KVMIO, 0x00) @@ -953,6 +962,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_NESTED_STATE 157 #define KVM_CAP_ARM_INJECT_SERROR_ESR 158 #define KVM_CAP_MSR_PLATFORM_INFO 159 +#define KVM_CAP_ARM_VM_IPA_SIZE 160 /* returns maximum IPA bits for a VM */ #ifdef KVM_CAP_IRQ_ROUTING |