In order to be able to detect the point where the guest enables
its MMU and caches, trap all the VM related system registers.
Once we see the guest enabling both the MMU and the caches, we
can go back to a saner mode of operation, which is to leave these
registers in complete control of the guest.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Commit 240e99cbd0 (ARM: KVM: Fix 64-bit coprocessor handling)
added an ordering dependency for the 64bit registers.
The order described is: CRn, CRm, Op1, Op2, 64bit-first.
Unfortunately, the implementation is: CRn, 64bit-first, CRm...
Move the 64bit test to be last in order to match the documentation.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 240e99cbd0 (ARM: KVM: Fix 64-bit coprocessor handling)
changed the way we match the 64bit coprocessor access from
user space, but didn't update the trap handler for the same
set of registers.
The effect is that a trapped 64bit access is never matched, leading
to a fault being injected into the guest. This went unnoticed as we
didn't really trap any 64bit register so far.
Placing the CRm field of the access into the CRn field of the matching
structure fixes the problem. Also update the debug feature to emit the
expected string in case of failing match.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
The PAR was exported as CRn == 7 and CRm == 0, but in fact the primary
coprocessor register number was determined by CRm for 64-bit coprocessor
registers as the user space API was modeled after the coprocessor
access instructions (see the ARM ARM rev. C - B3-1445).
However, just changing the CRn to CRm breaks the sorting check when
booting the kernel, because the internal kernel logic always treats CRn
as the primary register number, and it makes the table sorting
impossible to understand for humans.
Alternatively we could change the logic to always have CRn == CRm, but
that becomes unclear in the number of ways we do look up of a coprocessor
register. We could also have a separate 64-bit table but that feels
somewhat over-engineered. Instead, keep CRn the primary representation
of the primary coproc. register number in-kernel and always export the
primary number as CRm as per the existing user space ABI.
Note: The TTBR registers just magically worked because they happened to
follow the CRn(0) regs and were considered CRn(0) in the in-kernel
representation.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
On 32bit ARM, unsigned long is guaranteed to be a 32bit quantity.
On 64bit ARM, it is a 64bit quantity.
In order to be able to share code between the two architectures,
convert the registers to be unsigned long, so the core code can
be oblivious of the change.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Adds a new important function in the main KVM/ARM code called
handle_exit() which is called from kvm_arch_vcpu_ioctl_run() on returns
from guest execution. This function examines the Hyp-Syndrome-Register
(HSR), which contains information telling KVM what caused the exit from
the guest.
Some of the reasons for an exit are CP15 accesses, which are
not allowed from the guest and this commit handles these exits by
emulating the intended operation in software and skipping the guest
instruction.
Minor notes about the coproc register reset:
1) We reserve a value of 0 as an invalid cp15 offset, to catch bugs in our
table, at cost of 4 bytes per vcpu.
2) Added comments on the table indicating how we handle each register, for
simplicity of understanding.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Marc Zyngier