We introduce vgic_v3_rdist_free_slot to help identifying
where we can place a new 2x64KB redistributor.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
At the moment KVM supports a single rdist region. We want to
support several separate rdist regions so let's introduce a list
of them. This patch currently only cares about a single
entry in this list as the functionality to register several redist
regions is not yet there. So this only translates the existing code
into something functionally similar using that new data struct.
The redistributor region handle is stored in the vgic_cpu structure
to allow later computation of the TYPER last bit.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
in case kvm_vgic_map_resources() fails, typically if the vgic
distributor is not defined, __kvm_vgic_destroy will be called
several times. Indeed kvm_vgic_map_resources() is called on
first vcpu run. As a result dist->spis is freeed more than once
and on the second time it causes a "kernel BUG at mm/slub.c:3912!"
Set dist->spis to NULL to avoid the crash.
Fixes: ad275b8bb1 ("KVM: arm/arm64: vgic-new: vgic_init: implement
vgic_init")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Now that the host SVE context can be saved on demand from Hyp,
there is no longer any need to save this state in advance before
entering the guest.
This patch removes the relevant call to
kvm_fpsimd_flush_cpu_state().
Since the problem that function was intended to solve now no longer
exists, the function and its dependencies are also deleted.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This patch adds SVE context saving to the hyp FPSIMD context switch
path. This means that it is no longer necessary to save the host
SVE state in advance of entering the guest, when in use.
In order to avoid adding pointless complexity to the code, VHE is
assumed if SVE is in use. VHE is an architectural prerequisite for
SVE, so there is no good reason to turn CONFIG_ARM64_VHE off in
kernels that support both SVE and KVM.
Historically, software models exist that can expose the
architecturally invalid configuration of SVE without VHE, so if
this situation is detected at kvm_init() time then KVM will be
disabled.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This patch refactors KVM to align the host and guest FPSIMD
save/restore logic with each other for arm64. This reduces the
number of redundant save/restore operations that must occur, and
reduces the common-case IRQ blackout time during guest exit storms
by saving the host state lazily and optimising away the need to
restore the host state before returning to the run loop.
Four hooks are defined in order to enable this:
* kvm_arch_vcpu_run_map_fp():
Called on PID change to map necessary bits of current to Hyp.
* kvm_arch_vcpu_load_fp():
Set up FP/SIMD for entering the KVM run loop (parse as
"vcpu_load fp").
* kvm_arch_vcpu_ctxsync_fp():
Get FP/SIMD into a safe state for re-enabling interrupts after a
guest exit back to the run loop.
For arm64 specifically, this involves updating the host kernel's
FPSIMD context tracking metadata so that kernel-mode NEON use
will cause the vcpu's FPSIMD state to be saved back correctly
into the vcpu struct. This must be done before re-enabling
interrupts because kernel-mode NEON may be used by softirqs.
* kvm_arch_vcpu_put_fp():
Save guest FP/SIMD state back to memory and dissociate from the
CPU ("vcpu_put fp").
Also, the arm64 FPSIMD context switch code is updated to enable it
to save back FPSIMD state for a vcpu, not just current. A few
helpers drive this:
* fpsimd_bind_state_to_cpu(struct user_fpsimd_state *fp):
mark this CPU as having context fp (which may belong to a vcpu)
currently loaded in its registers. This is the non-task
equivalent of the static function fpsimd_bind_to_cpu() in
fpsimd.c.
* task_fpsimd_save():
exported to allow KVM to save the guest's FPSIMD state back to
memory on exit from the run loop.
* fpsimd_flush_state():
invalidate any context's FPSIMD state that is currently loaded.
Used to disassociate the vcpu from the CPU regs on run loop exit.
These changes allow the run loop to enable interrupts (and thus
softirqs that may use kernel-mode NEON) without having to save the
guest's FPSIMD state eagerly.
Some new vcpu_arch fields are added to make all this work. Because
host FPSIMD state can now be saved back directly into current's
thread_struct as appropriate, host_cpu_context is no longer used
for preserving the FPSIMD state. However, it is still needed for
preserving other things such as the host's system registers. To
avoid ABI churn, the redundant storage space in host_cpu_context is
not removed for now.
arch/arm is not addressed by this patch and continues to use its
current save/restore logic. It could provide implementations of
the helpers later if desired.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
KVM/ARM differs from other architectures in having to maintain an
additional virtual address space from that of the host and the
guest, because we split the execution of KVM across both EL1 and
EL2.
This results in a need to explicitly map data structures into EL2
(hyp) which are accessed from the hyp code. As we are about to be
more clever with our FPSIMD handling on arm64, which stores data in
the task struct and uses thread_info flags, we will have to map
parts of the currently executing task struct into the EL2 virtual
address space.
However, we don't want to do this on every KVM_RUN, because it is a
fairly expensive operation to walk the page tables, and the common
execution mode is to map a single thread to a VCPU. By introducing
a hook that architectures can select with
HAVE_KVM_VCPU_RUN_PID_CHANGE, we do not introduce overhead for
other architectures, but have a simple way to only map the data we
need when required for arm64.
This patch introduces the framework only, and wires it up in the
arm/arm64 KVM common code.
No functional change.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
kvm_read_guest() will eventually look up in kvm_memslots(), which requires
either to hold the kvm->slots_lock or to be inside a kvm->srcu critical
section.
In contrast to x86 and s390 we don't take the SRCU lock on every guest
exit, so we have to do it individually for each kvm_read_guest() call.
Use the newly introduced wrapper for that.
Cc: Stable <stable@vger.kernel.org> # 4.12+
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_read_guest() will eventually look up in kvm_memslots(), which requires
either to hold the kvm->slots_lock or to be inside a kvm->srcu critical
section.
In contrast to x86 and s390 we don't take the SRCU lock on every guest
exit, so we have to do it individually for each kvm_read_guest() call.
Provide a wrapper which does that and use that everywhere.
Note that ending the SRCU critical section before returning from the
kvm_read_guest() wrapper is safe, because the data has been *copied*, so
we don't need to rely on valid references to the memslot anymore.
Cc: Stable <stable@vger.kernel.org> # 4.8+
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Apparently the development of update_affinity() overlapped with the
promotion of irq_lock to be _irqsave, so the patch didn't convert this
lock over. This will make lockdep complain.
Fix this by disabling IRQs around the lock.
Cc: stable@vger.kernel.org
Fixes: 08c9fd0421 ("KVM: arm/arm64: vITS: Add a helper to update the affinity of an LPI")
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
As Jan reported [1], lockdep complains about the VGIC not being bullet
proof. This seems to be due to two issues:
- When commit 006df0f349 ("KVM: arm/arm64: Support calling
vgic_update_irq_pending from irq context") promoted irq_lock and
ap_list_lock to _irqsave, we forgot two instances of irq_lock.
lockdeps seems to pick those up.
- If a lock is _irqsave, any other locks we take inside them should be
_irqsafe as well. So the lpi_list_lock needs to be promoted also.
This fixes both issues by simply making the remaining instances of those
locks _irqsave.
One irq_lock is addressed in a separate patch, to simplify backporting.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/575718.html
Cc: stable@vger.kernel.org
Fixes: 006df0f349 ("KVM: arm/arm64: Support calling vgic_update_irq_pending from irq context")
Reported-by: Jan Glauber <jan.glauber@caviumnetworks.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM/arm fixes for 4.17, take #2
- Fix proxying of GICv2 CPU interface accesses
- Fix crash when switching to BE
- Track source vcpu git GICv2 SGIs
- Fix an outdated bit of documentation
One comment still mentioned process_maintenance operations after
commit af0614991a ("KVM: arm/arm64: vgic: Get rid of unnecessary
process_maintenance operation")
Update the comment to point to vgic_fold_lr_state instead, which
is where maintenance interrupts are taken care of.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Pull KVM fixes from Radim Krčmář:
"ARM:
- PSCI selection API, a leftover from 4.16 (for stable)
- Kick vcpu on active interrupt affinity change
- Plug a VMID allocation race on oversubscribed systems
- Silence debug messages
- Update Christoffer's email address (linaro -> arm)
x86:
- Expose userspace-relevant bits of a newly added feature
- Fix TLB flushing on VMX with VPID, but without EPT"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
x86/headers/UAPI: Move DISABLE_EXITS KVM capability bits to the UAPI
kvm: apic: Flush TLB after APIC mode/address change if VPIDs are in use
arm/arm64: KVM: Add PSCI version selection API
KVM: arm/arm64: vgic: Kick new VCPU on interrupt migration
arm64: KVM: Demote SVE and LORegion warnings to debug only
MAINTAINERS: Update e-mail address for Christoffer Dall
KVM: arm/arm64: Close VMID generation race
Now that we make sure we don't inject multiple instances of the
same GICv2 SGI at the same time, we've made another bug more
obvious:
If we exit with an active SGI, we completely lose track of which
vcpu it came from. On the next entry, we restore it with 0 as a
source, and if that wasn't the right one, too bad. While this
doesn't seem to trouble GIC-400, the architectural model gets
offended and doesn't deactivate the interrupt on EOI.
Another connected issue is that we will happilly make pending
an interrupt from another vcpu, overriding the above zero with
something that is just as inconsistent. Don't do that.
The final issue is that we signal a maintenance interrupt when
no pending interrupts are present in the LR. Assuming we've fixed
the two issues above, we end-up in a situation where we keep
exiting as soon as we've reached the active state, and not be
able to inject the following pending.
The fix comes in 3 parts:
- GICv2 SGIs have their source vcpu saved if they are active on
exit, and restored on entry
- Multi-SGIs cannot go via the Pending+Active state, as this would
corrupt the source field
- Multi-SGIs are converted to using MI on EOI instead of NPIE
Fixes: 16ca6a607d ("KVM: arm/arm64: vgic: Don't populate multiple LRs with the same vintid")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
It's possible for userspace to control n. Sanitize n when using it as an
array index.
Note that while it appears that n must be bound to the interval [0,3]
due to the way it is extracted from addr, we cannot guarantee that
compiler transformations (and/or future refactoring) will ensure this is
the case, and given this is a slow path it's better to always perform
the masking.
Found by smatch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Will Deacon <will.deacon@arm.com>
Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.
Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.
The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.
In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.
Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Although we've implemented PSCI 0.1, 0.2 and 1.0, we expose either 0.1
or 1.0 to a guest, defaulting to the latest version of the PSCI
implementation that is compatible with the requested version. This is
no different from doing a firmware upgrade on KVM.
But in order to give a chance to hypothetical badly implemented guests
that would have a fit by discovering something other than PSCI 0.2,
let's provide a new API that allows userspace to pick one particular
version of the API.
This is implemented as a new class of "firmware" registers, where
we expose the PSCI version. This allows the PSCI version to be
save/restored as part of a guest migration, and also set to
any supported version if the guest requires it.
Cc: stable@vger.kernel.org #4.16
Reviewed-by: Christoffer Dall <cdall@kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
When vgic_prune_ap_list() finds an interrupt that needs to be migrated
to a new VCPU, we should notify this VCPU of the pending interrupt,
since it requires immediate action.
Kick this VCPU once we have added the new IRQ to the list, but only
after dropping the locks.
Reported-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Before entering the guest, we check whether our VMID is still
part of the current generation. In order to avoid taking a lock,
we start with checking that the generation is still current, and
only if not current do we take the lock, recheck, and update the
generation and VMID.
This leaves open a small race: A vcpu can bump up the global
generation number as well as the VM's, but has not updated
the VMID itself yet.
At that point another vcpu from the same VM comes in, checks
the generation (and finds it not needing anything), and jumps
into the guest. At this point, we end-up with two vcpus belonging
to the same VM running with two different VMIDs. Eventually, the
VMID used by the second vcpu will get reassigned, and things will
really go wrong...
A simple solution would be to drop this initial check, and always take
the lock. This is likely to cause performance issues. A middle ground
is to convert the spinlock to a rwlock, and only take the read lock
on the fast path. If the check fails at that point, drop it and
acquire the write lock, rechecking the condition.
This ensures that the above scenario doesn't occur.
Cc: stable@vger.kernel.org
Reported-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
KVM/ARM updates for v4.17
- VHE optimizations
- EL2 address space randomization
- Variant 3a mitigation for Cortex-A57 and A72
- The usual vgic fixes
- Various minor tidying-up
vgic_copy_lpi_list() parses the LPI list and picks LPIs targeting
a given vcpu. We allocate the array containing the intids before taking
the lpi_list_lock, which means we can have an array size that is not
equal to the number of LPIs.
This is particularly obvious when looking at the path coming from
vgic_enable_lpis, which is not a command, and thus can run in parallel
with commands:
vcpu 0: vcpu 1:
vgic_enable_lpis
its_sync_lpi_pending_table
vgic_copy_lpi_list
intids = kmalloc_array(irq_count)
MAPI(lpi targeting vcpu 0)
list_for_each_entry(lpi_list_head)
intids[i++] = irq->intid;
At that stage, we will happily overrun the intids array. Boo. An easy
fix is is to break once the array is full. The MAPI command will update
the config anyway, and we won't miss a thing. We also make sure that
lpi_list_count is read exactly once, so that further updates of that
value will not affect the array bound check.
Cc: stable@vger.kernel.org
Fixes: ccb1d791ab ("KVM: arm64: vgic-its: Fix pending table sync")
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
It was recently reported that VFIO mediated devices, and anything
that VFIO exposes as level interrupts, do no strictly follow the
expected logic of such interrupts as it only lowers the input
line when the guest has EOId the interrupt at the GIC level, rather
than when it Acked the interrupt at the device level.
THe GIC's Active+Pending state is fundamentally incompatible with
this behaviour, as it prevents KVM from observing the EOI, and in
turn results in VFIO never dropping the line. This results in an
interrupt storm in the guest, which it really never expected.
As we cannot really change VFIO to follow the strict rules of level
signalling, let's forbid the A+P state altogether, as it is in the
end only an optimization. It ensures that we will transition via
an invalid state, which we can use to notify VFIO of the EOI.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Eric Auger
Dave Martin
Christoffer Dall
Andre Przywara
Radim Krčmář
Valentin Schneider
Linus Torvalds
Marc Zyngier
Mark Rutland
Eric W. Biederman