kvm: arm64: Switch to per VM IPA limit

Now that we can manage the stage2 page table per VM, switch the
configuration details to per VM instance. The VTCR is updated
with the values s

kvm: arm64: Switch to per VM IPA limit

Now that we can manage the stage2 page table per VM, switch the
configuration details to per VM instance. The VTCR is updated
with the values specific to the VM based on the configuration.
We store the IPA size and the number of stage2 page table levels
for the guest already in VTCR. Decode it back from the vtcr
field wherever we need it.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

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kvm: arm64: Make stage2 page table layout dynamic

Switch to dynamic stage2 page table layout based on the given
VM. So far we had a common stage2 table layout determined at
compile t

kvm: arm64: Make stage2 page table layout dynamic

Switch to dynamic stage2 page table layout based on the given
VM. So far we had a common stage2 table layout determined at
compile time. Make decision based on the VM instance depending
on the IPA limit for the VM. Adds helpers to compute the stage2
parameters based on the guest's IPA and uses them to make the decisions.

The IPA limit is still fixed to 40bits and the build time check
to ensure the stage2 doesn't exceed the host kernels page table
levels is retained. Also make sure that we use the pud/pmd level
helpers from the host only when they are not folded.

Cc: Christoffer Dall <cdall@kernel.org>
Cc: Marc Zyngier <marc.zyngier@arm.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>

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kvm: arm64: Prepare for dynamic stage2 page table layout

Our stage2 page table helpers are statically defined based
on the fixed IPA of 40bits and the host page size. As we are
about

kvm: arm64: Prepare for dynamic stage2 page table layout

Our stage2 page table helpers are statically defined based
on the fixed IPA of 40bits and the host page size. As we are
about to add support for configurable IPA size for VMs, we
need to make the page table checks for each VM. This patch
prepares the stage2 helpers to make the transition to a VM
dependent table layout easier. Instead of statically defining
the table helpers based on the page table levels, we now
check the page table levels in the helpers to do the right
thing. In effect, it simply converts the macros to static
inline functions.

Cc: Eric Auger <eric.auger@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

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kvm: arm/arm64: Prepare for VM specific stage2 translations

Right now the stage2 page table for a VM is hard coded, assuming
an IPA of 40bits. As we are about to add support for per VM I

kvm: arm/arm64: Prepare for VM specific stage2 translations

Right now the stage2 page table for a VM is hard coded, assuming
an IPA of 40bits. As we are about to add support for per VM IPA,
prepare the stage2 page table helpers to accept the kvm instance
to make the right decision for the VM. No functional changes.
Adds stage2_pgd_size(kvm) to replace S2_PGD_SIZE. Also, moves
some of the definitions in arm32 to align with the arm64.
Also drop the _AC() specifier constants wherever possible.

Cc: Christoffer Dall <cdall@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.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>

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kvm: arm64: Get rid of fake page table levels

On arm64, the hardware supports concatenation of upto 16 tables,
at entry level for stage2 translations and we make use that whenever
po

kvm: arm64: Get rid of fake page table levels

On arm64, the hardware supports concatenation of upto 16 tables,
at entry level for stage2 translations and we make use that whenever
possible. This could lead to reduced number of translation levels than
the normal (stage1 table) table. Also, since the IPA(40bit) is smaller
than the some of the supported VA_BITS (e.g, 48bit), there could be
different number of levels in stage-1 vs stage-2 tables. To reuse the
kernel host page table walker for stage2 we have been using a fake
software page table level, not known to the hardware. But with 16K
translations, there could be upto 2 fake software levels (with 48bit VA
and 40bit IPA), which complicates the code. Hence, we want to get rid of
the hack.

Now that we have explicit accessors for hyp vs stage2 page tables,
define the stage2 walker helpers accordingly based on the actual
table used by the hardware.

Once we know the number of translation levels used by the hardware,
it is merely a job of defining the helpers based on whether a
particular level is folded or not, looking at the number of levels.

Some facts before we calculate the translation levels:

1) Smallest page size supported by arm64 is 4K.
2) The minimum number of bits resolved at any page table level
is (PAGE_SHIFT - 3) at intermediate levels.
Both of them implies, minimum number of bits required for a level
change is 9.

Since we can concatenate upto 16 tables at stage2 entry, the total
number of page table levels used by the hardware for resolving N bits
is same as that for (N - 4) bits (with concatenation), as there cannot
be a level in between (N, N-4) as per the above rules.

Hence, we have

STAGE2_PGTABLE_LEVELS = PGTABLE_LEVELS(KVM_PHYS_SHIFT - 4)

With the current IPA limit (40bit), for all supported translations
and VA_BITS, we have the following condition (even for 36bit VA with
16K page size):

CONFIG_PGTABLE_LEVELS >= STAGE2_PGTABLE_LEVELS.

So, for e.g, if PUD is present in stage2, it is present in the hyp(host).
Hence, we fall back to the host definition if we find that a level is not
folded. Otherwise we redefine it accordingly. A build time check is added
to make sure the above condition holds. If this condition breaks in future,
we can rearrange the host level helpers and fix our code easily.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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kvm-arm: arm64: Introduce stage2 page table helpers

Introduce stage2 page table helpers for arm64. With the fake
page table level still in place, the stage2 table has the same
number

kvm-arm: arm64: Introduce stage2 page table helpers

Introduce stage2 page table helpers for arm64. With the fake
page table level still in place, the stage2 table has the same
number of levels as that of the host (and hyp), so they all
fallback to the host version.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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