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* kvm-arm64/nv-resx-fixes-6.14:
: .
: Fixes for NV sysreg accessors. From the cover letter:
:
: "Joey recently reported that some rather basic tests were failing on
: NV, and managed to track it down to critical register fields (such as
: HCR_EL2.E2H) not having their expect value.
:
: Further investigation has outlined a couple of critical issues:
:
: - Evaluating HCR_EL2.E2H must always be done with a sanitising
: accessor, no ifs, no buts. Given that KVM assumes a fixed value for
: this bit, we cannot leave it to the guest to mess with.
:
: - Resetting the sysreg file must result in the RESx bits taking
: effect. Otherwise, we may end-up making the wrong decision (see
: above), and we definitely expose invalid values to the guest. Note
: that because we compute the RESx masks very late in the VM setup, we
: need to apply these masks at that particular point as well.
: [...]"
: .
KVM: arm64: nv: Apply RESx settings to sysreg reset values
KVM: arm64: nv: Always evaluate HCR_EL2 using sanitising accessors
Signed-off-by: Marc Zyngier <maz@kernel.org>
# Conflicts:
# arch/arm64/kvm/nested.c
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While we have sanitisation in place for the guest sysregs, we lack
that sanitisation out of reset. So some of the fields could be
evaluated and not reflect their RESx status, which sounds like
a very bad idea.
Apply the RESx masks to the the sysreg file in two situations:
- when going via a reset of the sysregs
- after having computed the RESx masks
Having this separate reset phase from the actual reset handling is
a bit grotty, but we need to apply this after the ID registers are
final.
Tested-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250112165029.1181056-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/pkvm-fixed-features-6.14: (24 commits)
: .
: Complete rework of the pKVM handling of features, catching up
: with the rest of the code deals with it these days.
: Patches courtesy of Fuad Tabba. From the cover letter:
:
: "This patch series uses the vm's feature id registers to track the
: supported features, a framework similar to nested virt to set the
: trap values, and removes the need to store cptr_el2 per vcpu in
: favor of setting its value when traps are activated, as VHE mode
: does."
:
: This branch drags the arm64/for-next/cpufeature branch to solve
: ugly conflicts in -next.
: .
KVM: arm64: Fix FEAT_MTE in pKVM
KVM: arm64: Use kvm_vcpu_has_feature() directly for struct kvm
KVM: arm64: Convert the SVE guest vcpu flag to a vm flag
KVM: arm64: Remove PtrAuth guest vcpu flag
KVM: arm64: Fix the value of the CPTR_EL2 RES1 bitmask for nVHE
KVM: arm64: Refactor kvm_reset_cptr_el2()
KVM: arm64: Calculate cptr_el2 traps on activating traps
KVM: arm64: Remove redundant setting of HCR_EL2 trap bit
KVM: arm64: Remove fixed_config.h header
KVM: arm64: Rework specifying restricted features for protected VMs
KVM: arm64: Set protected VM traps based on its view of feature registers
KVM: arm64: Fix RAS trapping in pKVM for protected VMs
KVM: arm64: Initialize feature id registers for protected VMs
KVM: arm64: Use KVM extension checks for allowed protected VM capabilities
KVM: arm64: Remove KVM_ARM_VCPU_POWER_OFF from protected VMs allowed features in pKVM
KVM: arm64: Move checking protected vcpu features to a separate function
KVM: arm64: Group setting traps for protected VMs by control register
KVM: arm64: Consolidate allowed and restricted VM feature checks
arm64/sysreg: Get rid of CPACR_ELx SysregFields
arm64/sysreg: Convert *_EL12 accessors to Mapping
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
# Conflicts:
# arch/arm64/kvm/fpsimd.c
# arch/arm64/kvm/hyp/nvhe/pkvm.c
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Inject debug exceptions into vEL2 if MDCR_EL2.TDE is set.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-17-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
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There is no such thing as CPACR_ELx in the architecture.
What we have is CPACR_EL1, for which CPTR_EL12 is an accessor.
Rename CPACR_ELx_* to CPACR_EL1_*, and fix the bit of code using
these names.
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241219173351.1123087-5-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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Currently, when a nested MMU is repurposed for some other MMU context,
KVM unmaps everything during vcpu_load() while holding the MMU lock for
write. This is quite a performance bottleneck for large nested VMs, as
all vCPU scheduling will spin until the unmap completes.
Start punting the MMU cleanup to a vCPU request, where it is then
possible to periodically release the MMU lock and CPU in the presence of
contention.
Ensure that no vCPU winds up using a stale MMU by tracking the pending
unmap on the S2 MMU itself and requesting an unmap on every vCPU that
finds it.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Right now the nested code allows unmap operations on a shadow stage-2 to
block unconditionally. This is wrong in a couple places, such as a
non-blocking MMU notifier or on the back of a sched_in() notifier as
part of shadow MMU recycling.
Carry through whether or not blocking is allowed to
kvm_pgtable_stage2_unmap(). This 'fixes' an issue where stage-2 MMU
reclaim would precipitate a stack overflow from a pile of kvm_sched_in()
callbacks, all trying to recycle a stage-2 MMU.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Make this helper visible to at.c, we are going to need it.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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The upper_attr attribute has been badly named, as it most of the
time carries the full "last walked descriptor".
Rename it to "desc" and make ti contain the full 64bit descriptor.
This will be used by the S1 PTW.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Despite KVM not using the contiguous bit for anything related to
TLBs, the spec does require that the alignment defined by the
contiguous bit for the page size and the level is enforced.
Add the required checks to offset the point where PA and VA merge.
Fixes: 61e30b9eef7f ("KVM: arm64: nv: Implement nested Stage-2 page table walk logic")
Reported-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/nv-sve:
: CPTR_EL2, FPSIMD/SVE support for nested
:
: This series brings support for honoring the guest hypervisor's CPTR_EL2
: trap configuration when running a nested guest, along with support for
: FPSIMD/SVE usage at L1 and L2.
KVM: arm64: Allow the use of SVE+NV
KVM: arm64: nv: Add additional trap setup for CPTR_EL2
KVM: arm64: nv: Add trap description for CPTR_EL2
KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper
KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
KVM: arm64: nv: Handle CPACR_EL1 traps
KVM: arm64: Spin off helper for programming CPTR traps
KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
KVM: arm64: nv: Use guest hypervisor's max VL when running nested guest
KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
KVM: arm64: nv: Handle ZCR_EL2 traps
KVM: arm64: nv: Forward SVE traps to guest hypervisor
KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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We are missing the propagation of CPTR_EL2.{TCPAC,TTA} into
the CPACR format. Make sure we preserve these bits.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-13-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Populate bits [56:55] of the leaf entry with the level provided
by the guest's S2 translation. This will allow us to better scope
the invalidation by remembering the mapping size.
Of course, this assume that the guest will issue an invalidation
with an address that falls into the same leaf. If the guest doesn't,
we'll over-invalidate.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-13-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Support guest-provided information information to size the range of
required invalidation. This helps with reducing over-invalidation,
provided that the guest actually provides accurate information.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-12-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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While dealing with TLB invalidation targeting the guest hypervisor's
own stage-1 was easy, doing the same thing for its own guests is
a bit more involved.
Since such an invalidation is scoped by VMID, it needs to apply to
all s2_mmu contexts that have been tagged by that VMID, irrespective
of the value of VTTBR_EL2.BADDR.
So for each s2_mmu context matching that VMID, we invalidate the
corresponding TLBs, each context having its own "physical" VMID.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-8-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Due to the way FEAT_NV2 suppresses traps when accessing EL2
system registers, we can't track when the guest changes its
HCR_EL2.TGE setting. This means we always trap EL1 TLBIs,
even if they don't affect any L2 guest.
Given that invalidating the EL2 TLBs doesn't require any messing
with the shadow stage-2 page-tables, we can simply emulate the
instructions early and return directly to the guest.
This is conditioned on the instruction being an EL1 one and
the guest's HCR_EL2.{E2H,TGE} being {1,1} (indicating that
the instruction targets the EL2 S1 TLBs), or the instruction
being one of the EL2 ones (which are not ambiguous).
EL1 TLBIs issued with HCR_EL2.{E2H,TGE}={1,0} are not handled
here, and cause a full exit so that they can be handled in
the context of a VMID.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-7-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Unmap/flush shadow stage 2 page tables for the nested VMs as well as the
stage 2 page table for the guest hypervisor.
Note: A bunch of the code in mmu.c relating to MMU notifiers is
currently dealt with in an extremely abrupt way, for example by clearing
out an entire shadow stage-2 table. This will be handled in a more
efficient way using the reverse mapping feature in a later version of
the patch series.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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If we are faulting on a shadow stage 2 translation, we first walk the
guest hypervisor's stage 2 page table to see if it has a mapping. If
not, we inject a stage 2 page fault to the virtual EL2. Otherwise, we
create a mapping in the shadow stage 2 page table.
Note that we have to deal with two IPAs when we got a shadow stage 2
page fault. One is the address we faulted on, and is in the L2 guest
phys space. The other is from the guest stage-2 page table walk, and is
in the L1 guest phys space. To differentiate them, we rename variables
so that fault_ipa is used for the former and ipa is used for the latter.
When mapping a page in a shadow stage-2, special care must be taken not
to be more permissive than the guest is.
Co-developed-by: Christoffer Dall <christoffer.dall@linaro.org>
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Based on the pseudo-code in the ARM ARM, implement a stage 2 software
page table walker.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Add Stage-2 mmu data structures for virtual EL2 and for nested guests.
We don't yet populate shadow Stage-2 page tables, but we now have a
framework for getting to a shadow Stage-2 pgd.
We allocate twice the number of vcpus as Stage-2 mmu structures because
that's sufficient for each vcpu running two translation regimes without
having to flush the Stage-2 page tables.
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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FEAT_NV has the interesting property of relying on ERET being
trapped. An added complexity is that it also traps ERETAA and
ERETAB, meaning that the Pointer Authentication aspect of these
instruction must be emulated.
Add an emulation of Pointer Authentication, limited to ERETAx
(always using SP_EL2 as the modifier and ELR_EL2 as the pointer),
using the Generic Authentication instructions.
The emulation, however small, is placed in its own compilation
unit so that it can be avoided if the configuration doesn't
include it (or the toolchan in not up to the task).
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-13-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Honor the trap forwarding bits for both ERET and SMC, using a new
helper that checks for common conditions.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-7-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
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__check_nv_sr_forward() is not specific to NV anymore, and does
a lot more. Rename it to triage_sysreg_trap(), making it plain
that its role is to handle where an exception is to be handled.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-17-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Since we always start sysreg/sysinsn handling by searching the
xarray, use it as the source of the index in the correct sys_reg_desc
array.
This allows some cleanup, such as moving the handling of unknown
sysregs in a single location.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-16-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Some EL2 system registers immediately affect the current execution
of the system, so we need to use their respective EL1 counterparts.
For this we need to define a mapping between the two. In general,
this only affects non-VHE guest hypervisors, as VHE system registers
are compatible with the EL1 counterparts.
These helpers will get used in subsequent patches.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Co-developed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Now that we have a full copy of the idregs for each VM, there is
no point in repainting the sysregs on each access. Instead, we
can simply perform the transmation as a one-off and be done
with it.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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The vCPU-scoped feature bitmap was left in place a couple of releases
ago in case the change to VM-scoped vCPU features broke anyone. Nobody
has complained and the interop between VM and vCPU bitmaps is pretty
gross. Throw it out.
Link: https://lore.kernel.org/r/20230920195036.1169791-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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A significant part of what a NV hypervisor needs to do is to decide
whether a trap from a L2+ guest has to be forwarded to a L1 guest
or handled locally. This is done by checking for the trap bits that
the guest hypervisor has set and acting accordingly, as described by
the architecture.
A previous approach was to sprinkle a bunch of checks in all the
system register accessors, but this is pretty error prone and doesn't
help getting an overview of what is happening.
Instead, implement a set of global tables that describe a trap bit,
combinations of trap bits, behaviours on trap, and what bits must
be evaluated on a system register trap.
Although this is painful to describe, this allows to specify each
and every control bit in a static manner. To make it efficient,
the table is inserted in an xarray that is global to the system,
and checked each time we trap a system register while running
a L2 guest.
Add the basic infrastructure for now, while additional patches will
implement configuration registers.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Link: https://lore.kernel.org/r/20230815183903.2735724-15-maz@kernel.org
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As there is a number of features that we either can't support,
or don't want to support right away with NV, let's add some
basic filtering so that we don't advertize silly things to the
EL2 guest.
Whilst we are at it, advertize FEAT_TTL as well as FEAT_GTG, which
the NV implementation will implement.
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-18-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Introduce the feature bit and a primitive that checks if the feature is
set behind a static key check based on the cpus_have_const_cap check.
Checking vcpu_has_nv() on systems without nested virt enabled
should have negligible overhead.
We don't yet allow userspace to actually set this feature.
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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