While protected KVM is installed, start trapping all host SMCs.
For now these are simply forwarded to EL3, except PSCI
CPU_ON/CPU_SUSPEND/SYSTEM_SUSPEND which are intercepted and the
hypervisor installed on newly booted cores.
Create new constant HCR_HOST_NVHE_PROTECTED_FLAGS with the new set of HCR
flags to use while the nVHE vector is installed when the kernel was
booted with the protected flag enabled. Switch back to the default HCR
flags when switching back to the stub vector.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-26-dbrazdil@google.com
In an effort to remove the vcpu PC manipulations from EL1 on nVHE
systems, move kvm_skip_instr() to be HYP-specific. EL1's intent
to increment PC post emulation is now signalled via a flag in the
vcpu structure.
Signed-off-by: Marc Zyngier <maz@kernel.org>
On Cortex-A77 r0p0 and r1p0, a sequence of a non-cacheable or device load
and a store exclusive or PAR_EL1 read can cause a deadlock.
The workaround requires a DMB SY before and after a PAR_EL1 register
read. In addition, it's possible an interrupt (doing a device read) or
KVM guest exit could be taken between the DMB and PAR read, so we
also need a DMB before returning from interrupt and before returning to
a guest.
A deadlock is still possible with the workaround as KVM guests must also
have the workaround. IOW, a malicious guest can deadlock an affected
systems.
This workaround also depends on a firmware counterpart to enable the h/w
to insert DMB SY after load and store exclusive instructions. See the
errata document SDEN-1152370 v10 [1] for more information.
[1] https://static.docs.arm.com/101992/0010/Arm_Cortex_A77_MP074_Software_Developer_Errata_Notice_v10.pdf
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20201028182839.166037-2-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Host CPU context is stored in a global per-cpu variable `kvm_host_data`.
In preparation for introducing independent per-CPU region for nVHE hyp,
create two separate instances of `kvm_host_data`, one for VHE and one
for nVHE.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-9-dbrazdil@google.com
Hyp keeps track of which cores require SSBD callback by accessing a
kernel-proper global variable. Create an nVHE symbol of the same name
and copy the value from kernel proper to nVHE as KVM is being enabled
on a core.
Done in preparation for separating percpu memory owned by kernel
proper and nVHE.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-8-dbrazdil@google.com
this_cpu_ptr is meant for use in kernel proper because it selects between
TPIDR_EL1/2 based on nVHE/VHE. __hyp_this_cpu_ptr was used in hyp to always
select TPIDR_EL2. Unify all users behind this_cpu_ptr and friends by
selecting _EL2 register under __KVM_NVHE_HYPERVISOR__. VHE continues
selecting the register using alternatives.
Under CONFIG_DEBUG_PREEMPT, the kernel helpers perform a preemption check
which is omitted by the hyp helpers. Preserve the behavior for nVHE by
overriding the corresponding macros under __KVM_NVHE_HYPERVISOR__. Extend
the checks into VHE hyp code.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Andrew Scull <ascull@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-5-dbrazdil@google.com
Owing to the fact that the host kernel is always mitigated, we can
drastically simplify the WA2 handling by keeping the mitigation
state ON when entering the guest. This means the guest is either
unaffected or not mitigated.
This results in a nice simplification of the mitigation space,
and the removal of a lot of code that was never really used anyway.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
The host need not concern itself with the pointer differences for the
hyp interfaces that are shared between VHE and nVHE so leave it to the
hyp to handle.
As the SMCCC function IDs are converted into function calls, it is a
suitable place to also convert any pointer arguments into hyp pointers.
This, additionally, eases the reuse of the handlers in different
contexts.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-20-ascull@google.com
Restore the host context when panicking from hyp to give the best chance
of the panic being clean.
The host requires that registers be preserved such as x18 for the shadow
callstack. If the panic is caused by an exception from EL1, the host
context is still valid so the panic can return straight back to the
host. If the panic comes from EL2 then it's most likely that the hyp
context is active and the host context needs to be restored.
There are windows before and after the host context is saved and
restored that restoration is attempted incorrectly and the panic won't
be clean.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-14-ascull@google.com
During __guest_enter, save and restore from a new hyp context rather
than the host context. This is preparation for separation of the hyp and
host context in nVHE.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-9-ascull@google.com
The host is treated differently from the guests when an exception is
taken so introduce a separate vector that is specialized for the host.
This also allows the nVHE specific code to move out of hyp-entry.S and
into nvhe/host.S.
The host is only expected to make HVC calls and anything else is
considered invalid and results in a panic.
Hyp initialization is now passed the vector that is used for the host
and it is swapped for the guest vector during the context switch.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-7-ascull@google.com
hyp_panic is able to find all the context it needs from within itself so
remove the argument. The __hyp_panic wrapper becomes redundant so is
also removed.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-3-ascull@google.com
The __activate_vm wrapper serves no useful function and has a misleading
name as it simply calls __load_guest_stage2 and does not touch
HCR_EL2.VM so remove it.
Also rename __deactivate_vm to __load_host_stage2 to match naming
pattern.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-2-ascull@google.com
KVM has a one instruction window where it will allow an SError exception
to be consumed by the hypervisor without treating it as a hypervisor bug.
This is used to consume asynchronous external abort that were caused by
the guest.
As we are about to add another location that survives unexpected exceptions,
generalise this code to make it behave like the host's extable.
KVM's version has to be mapped to EL2 to be accessible on nVHE systems.
The SError vaxorcism code is a one instruction window, so has two entries
in the extable. Because the KVM code is copied for VHE and nVHE, we end up
with four entries, half of which correspond with code that isn't mapped.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Switch the hypervisor code to using ctxt_sys_reg/__vcpu_sys_reg instead
of raw sys_regs accesses. No intended functionnal change.
Signed-off-by: Marc Zyngier <maz@kernel.org>
As we are about to reuse our stage 2 page table manipulation code for
shadow stage 2 page tables in the context of nested virtualization, we
are going to manage multiple stage 2 page tables for a single VM.
This requires some pretty invasive changes to our data structures,
which moves the vmid and pgd pointers into a separate structure and
change pretty much all of our mmu code to operate on this structure
instead.
The new structure is called struct kvm_s2_mmu.
There is no intended functional change by this patch alone.
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
[Designed data structure layout in collaboration]
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Co-developed-by: Marc Zyngier <maz@kernel.org>
[maz: Moved the last_vcpu_ran down to the S2 MMU structure as well]
Signed-off-by: Marc Zyngier <maz@kernel.org>
With nVHE code now fully separated from the rest of the kernel, the effects of
the __hyp_text macro (which had to be applied on all nVHE code) can be
achieved with build rules instead. The macro used to:
(a) move code to .hyp.text ELF section, now done by renaming .text using
`objcopy`, and
(b) `notrace` and `__noscs` would negate effects of CC_FLAGS_FTRACE and
CC_FLAGS_SCS, respectivelly, now those flags are erased from
KBUILD_CFLAGS (same way as in EFI stub).
Note that by removing __hyp_text from code shared with VHE, all VHE code is now
compiled into .text and without `notrace` and `__noscs`.
Use of '.pushsection .hyp.text' removed from assembly files as this is now also
covered by the build rules.
For MAINTAINERS: if needed to re-run, uses of macro were removed with the
following command. Formatting was fixed up manually.
find arch/arm64/kvm/hyp -type f -name '*.c' -o -name '*.h' \
-exec sed -i 's/ __hyp_text//g' {} +
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-15-dbrazdil@google.com
sysreg-sr.c contains KVM's code for saving/restoring system registers, with
some code shared between VHE/nVHE. These common routines are moved to
a header file, VHE-specific code is moved to vhe/sysreg-sr.c and nVHE-specific
code to nvhe/sysreg-sr.c.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-12-dbrazdil@google.com
switch.c implements context-switching for KVM, with large parts shared between
VHE/nVHE. These common routines are moved to a header file, VHE-specific code
is moved to vhe/switch.c and nVHE-specific code is moved to nvhe/switch.c.
Previously __kvm_vcpu_run needed a different symbol name for VHE/nVHE. This
is cleaned up and the caller in arm.c simplified.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-10-dbrazdil@google.com
