sve_reg_to_region() currently passes the result of
vcpu_sve_state_size() to array_index_nospec(), effectively
leading to a divide / modulo operation.

Currently the code bails out and returns -EINVAL if
vcpu_sve_state_size() turns out to be zero, in order to avoid going
ahead and attempting to divide by zero.  This is reasonable, but it
should only happen if the kernel contains some other bug that
allowed this code to be reached without the vcpu having been
properly initialised.

To make it clear that this is a defence against bugs rather than
something that the user should be able to trigger, this patch marks
the check with WARN_ON().
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Currently, the way error codes are generated when processing the
SVE register access ioctls in a bit haphazard.

This patch refactors the code so that the behaviour is more
consistent: now, -EINVAL should be returned only for unrecognised
register IDs or when some other runtime error occurs.  -ENOENT is
returned for register IDs that are recognised, but whose
corresponding register (or slice) does not exist for the vcpu.

To this end, in {get,set}_sve_reg() we now delegate the
vcpu_has_sve() check down into {get,set}_sve_vls() and
sve_reg_to_region().  The KVM_REG_ARM64_SVE_VLS special case is
picked off first, then sve_reg_to_region() plays the role of
exhaustively validating or rejecting the register ID and (where
accepted) computing the applicable register region as before.

sve_reg_to_region() is rearranged so that -ENOENT or -EPERM is not
returned prematurely, before checking whether reg->id is in a
recognised range.

-EPERM is now only returned when an attempt is made to access an
actually existing register slice on an unfinalized vcpu.

Fixes: e1c9c983 ("KVM: arm64/sve: Add SVE support to register access ioctl interface")
Fixes: 9033bba4 ("KVM: arm64/sve: Add pseudo-register for the guest's vector lengths")
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

 * Remove a few redundant blank lines that are stylistically
   inconsistent with code already in guest.c and are just taking up
   space.

 * Delete a couple of pointless empty default cases from switch
   statements whose behaviour is otherwise obvious anyway.

 * Fix some typos and consolidate some redundantly duplicated
   comments.

 * Respell the slice index check in sve_reg_to_region() as "> 0"
   to be more consistent with what is logically being checked here
   (i.e., "is the slice index too large"), even though we don't try
   to cope with multiple slices yet.

No functional change.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Currently, the SVE register ID macros are not all defined in the
same way, and advertise the fact that FFR maps onto the nonexistent
predicate register P16.  This is really just for kernel
convenience, and may lead userspace into bad habits.

Instead, this patch masks the ID macro arguments so that
architecturally invalid register numbers will not be passed through
any more, and uses a literal KVM_REG_ARM64_SVE_FFR_BASE macro to
define KVM_REG_ARM64_SVE_FFR(), similarly to the way the _ZREG()
and _PREG() macros are defined.

Rather than plugging in magic numbers for the number of Z- and P-
registers and the maximum possible number of register slices, this
patch provides definitions for those too.  Userspace is going to
need them in any case, and it makes sense for them to come from
<uapi/asm/kvm.h>.

sve_reg_to_region() uses convenience constants that are defined in
a different way, and also makes use of the fact that the FFR IDs
are really contiguous with the P15 IDs, so this patch retains the
existing convenience constants in guest.c, supplemented with a
couple of sanity checks to check for consistency with the UAPI
header.

Fixes: e1c9c983 ("KVM: arm64/sve: Add SVE support to register access ioctl interface")
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Because of the logic in kvm_arm_sys_reg_{get,set}_reg() and
sve_id_visibility(), we should never call
{get,set}_id_aa64zfr0_el1() for a vcpu where !vcpu_has_sve(vcpu).

To avoid the code giving the impression that it is valid for these
functions to be called in this situation, and to help the compiler
make the right optimisation decisions, this patch adds WARN_ON()
for these cases.

Given the way the logic is spread out, this seems preferable to
dropping the checks altogether.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The vcpu finalization stubs kvm_arm_vcpu_finalize() and
kvm_arm_vcpu_is_finalized() are currently #defines for ARM, which
limits the type-checking that the compiler can do at runtime.

The only reason for them to be #defines was to avoid reliance on
the definition of struct kvm_vcpu, which is not available here due
to circular #include problems.  However, because these are stubs
containing no code, they don't need the definition of struct
kvm_vcpu after all; only a declaration is needed (which is
available already).

So in the interests of cleanliness, this patch converts them to
inline functions.

No functional change.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The introduction of kvm_arm_init_arch_resources() looks like
premature factoring, since nothing else uses this hook yet and it
is not clear what will use it in the future.

For now, let's not pretend that this is a general thing:

This patch simply renames the function to kvm_arm_init_sve(),
retaining the arm stub version under the new name.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Currently the meanings of sve_vq_map and the ancillary helpers
__bit_to_vq() and __vq_to_bit() are not clearly explained.

This patch makes the explanatory comment clearer, and removes the
duplicate comment from fpsimd.h.

The WARN_ON() currently present in __bit_to_vq() confuses the
intended use of this helper.  Since these are low-level helpers not
intended for general-purpose use anyway, it is better not to make
guesses about how these functions will be used: rather, this patch
removes the WARN_ON() and relies on callers to use the helpers
sensibly.
Suggested-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The introduction of the SVE registers to userspace started with a
refactoring of the way we expose any register via the ONE_REG
interface.

Unfortunately, this change doesn't exactly behave as expected
if the number of registers is non-zero and consider everything
to be an error. The visible result is that QEMU barfs very early
when creating vcpus.

Make sure we only exit early in case there is an actual error, rather
than a positive number of registers...

Fixes: be25bbb3 ("KVM: arm64: Factor out core register ID enumeration")
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch adds sections to the KVM API documentation describing
the extensions for supporting the Scalable Vector Extension (SVE)
in guests.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

KVM_GET_ONE_REG and KVM_SET_ONE_REG return some error codes that
are not documented (but hopefully not surprising either).  To give
an indication of what these may mean, this patch adds brief
documentation.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

To provide a uniform way to check for KVM SVE support amongst other
features, this patch adds a suitable capability KVM_CAP_ARM_SVE,
and reports it as present when SVE is available.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Now that all the pieces are in place, this patch offers a new flag
KVM_ARM_VCPU_SVE that userspace can pass to KVM_ARM_VCPU_INIT to
turn on SVE for the guest, on a per-vcpu basis.

As part of this, support for initialisation and reset of the SVE
vector length set and registers is added in the appropriate places,
as well as finally setting the KVM_ARM64_GUEST_HAS_SVE vcpu flag,
to turn on the SVE support code.

Allocation of the SVE register storage in vcpu->arch.sve_state is
deferred until the SVE configuration is finalized, by which time
the size of the registers is known.

Setting the vector lengths supported by the vcpu is considered
configuration of the emulated hardware rather than runtime
configuration, so no support is offered for changing the vector
lengths available to an existing vcpu across reset.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch adds a new pseudo-register KVM_REG_ARM64_SVE_VLS to
allow userspace to set and query the set of vector lengths visible
to the guest.

In the future, multiple register slices per SVE register may be
visible through the ioctl interface.  Once the set of slices has
been determined we would not be able to allow the vector length set
to be changed any more, in order to avoid userspace seeing
inconsistent sets of registers.  For this reason, this patch adds
support for explicit finalization of the SVE configuration via the
KVM_ARM_VCPU_FINALIZE ioctl.

Finalization is the proper place to allocate the SVE register state
storage in vcpu->arch.sve_state, so this patch adds that as
appropriate.  The data is freed via kvm_arch_vcpu_uninit(), which
was previously a no-op on arm64.

To simplify the logic for determining what vector lengths can be
supported, some code is added to KVM init to work this out, in the
kvm_arm_init_arch_resources() hook.

The KVM_REG_ARM64_SVE_VLS pseudo-register is not exposed yet.
Subsequent patches will allow SVE to be turned on for guest vcpus,
making it visible.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Some aspects of vcpu configuration may be too complex to be
completed inside KVM_ARM_VCPU_INIT.  Thus, there may be a
requirement for userspace to do some additional configuration
before various other ioctls will work in a consistent way.

In particular this will be the case for SVE, where userspace will
need to negotiate the set of vector lengths to be made available to
the guest before the vcpu becomes fully usable.

In order to provide an explicit way for userspace to confirm that
it has finished setting up a particular vcpu feature, this patch
adds a new ioctl KVM_ARM_VCPU_FINALIZE.

When userspace has opted into a feature that requires finalization,
typically by means of a feature flag passed to KVM_ARM_VCPU_INIT, a
matching call to KVM_ARM_VCPU_FINALIZE is now required before
KVM_RUN or KVM_GET_REG_LIST is allowed.  Individual features may
impose additional restrictions where appropriate.

No existing vcpu features are affected by this, so current
userspace implementations will continue to work exactly as before,
with no need to issue KVM_ARM_VCPU_FINALIZE.

As implemented in this patch, KVM_ARM_VCPU_FINALIZE is currently a
placeholder: no finalizable features exist yet, so ioctl is not
required and will always yield EINVAL.  Subsequent patches will add
the finalization logic to make use of this ioctl for SVE.

No functional change for existing userspace.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch adds a kvm_arm_init_arch_resources() hook to perform
subarch-specific initialisation when starting up KVM.

This will be used in a subsequent patch for global SVE-related
setup on arm64.

No functional change.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

KVM will need to interrogate the set of SVE vector lengths
available on the system.

This patch exposes the relevant bits to the kernel, along with a
sve_vq_available() helper to check whether a particular vector
length is supported.

__vq_to_bit() and __bit_to_vq() are not intended for use outside
these functions: now that these are exposed outside fpsimd.c, they
are prefixed with __ in order to provide an extra hint that they
are not intended for general-purpose use.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch includes the SVE register IDs in the list returned by
KVM_GET_REG_LIST, as appropriate.

On a non-SVE-enabled vcpu, no new IDs are added.

On an SVE-enabled vcpu, IDs for the FPSIMD V-registers are removed
from the list, since userspace is required to access the Z-
registers instead in order to access the V-register content.  For
the variably-sized SVE registers, the appropriate set of slice IDs
are enumerated, depending on the maximum vector length for the
vcpu.

As it currently stands, the SVE architecture never requires more
than one slice to exist per register, so this patch adds no
explicit support for enumerating multiple slices.  The code can be
extended straightforwardly to support this in the future, if
needed.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch adds the following registers for access via the
KVM_{GET,SET}_ONE_REG interface:

 * KVM_REG_ARM64_SVE_ZREG(n, i) (n = 0..31) (in 2048-bit slices)
 * KVM_REG_ARM64_SVE_PREG(n, i) (n = 0..15) (in 256-bit slices)
 * KVM_REG_ARM64_SVE_FFR(i) (in 256-bit slices)

In order to adapt gracefully to future architectural extensions,
the registers are logically divided up into slices as noted above:
the i parameter denotes the slice index.

This allows us to reserve space in the ABI for future expansion of
these registers.  However, as of today the architecture does not
permit registers to be larger than a single slice, so no code is
needed in the kernel to expose additional slices, for now.  The
code can be extended later as needed to expose them up to a maximum
of 32 slices (as carved out in the architecture itself) if they
really exist someday.

The registers are only visible for vcpus that have SVE enabled.
They are not enumerated by KVM_GET_REG_LIST on vcpus that do not
have SVE.

Accesses to the FPSIMD registers via KVM_REG_ARM_CORE is not
allowed for SVE-enabled vcpus: SVE-aware userspace can use the
KVM_REG_ARM64_SVE_ZREG() interface instead to access the same
register state.  This avoids some complex and pointless emulation
in the kernel to convert between the two views of these aliased
registers.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In order to avoid the pointless complexity of maintaining two ioctl
register access views of the same data, this patch blocks ioctl
access to the FPSIMD V-registers on vcpus that support SVE.

This will make it more straightforward to add SVE register access
support.

Since SVE is an opt-in feature for userspace, this will not affect
existing users.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In preparation for adding logic to filter out some KVM_REG_ARM_CORE
registers from the KVM_GET_REG_LIST output, this patch factors out
the core register enumeration into a separate function and rebuilds
num_core_regs() on top of it.

This may be a little more expensive (depending on how good a job
the compiler does of specialising the code), but KVM_GET_REG_LIST
is not a hot path.

This will make it easier to consolidate ID filtering code in one
place.

No functional change.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

arch/arm64/kvm/guest.c uses the string functions, but the
corresponding header is not included.

We seem to get away with this for now, but for completeness this
patch adds the #include, in preparation for adding yet more
memset() calls.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The Arm SVE architecture defines registers that are up to 2048 bits
in size (with some possibility of further future expansion).

In order to avoid the need for an excessively large number of
ioctls when saving and restoring a vcpu's registers, this patch
adds a #define to make support for individual 2048-bit registers
through the KVM_{GET,SET}_ONE_REG ioctl interface official.  This
will allow each SVE register to be accessed in a single call.

There are sufficient spare bits in the register id size field for
this change, so there is no ABI impact, providing that
KVM_GET_REG_LIST does not enumerate any 2048-bit register unless
userspace explicitly opts in to the relevant architecture-specific
features.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In order to give each vcpu its own view of the SVE registers, this
patch adds context storage via a new sve_state pointer in struct
vcpu_arch.  An additional member sve_max_vl is also added for each
vcpu, to determine the maximum vector length visible to the guest
and thus the value to be configured in ZCR_EL2.LEN while the vcpu
is active.  This also determines the layout and size of the storage
in sve_state, which is read and written by the same backend
functions that are used for context-switching the SVE state for
host tasks.

On SVE-enabled vcpus, SVE access traps are now handled by switching
in the vcpu's SVE context and disabling the trap before returning
to the guest.  On other vcpus, the trap is not handled and an exit
back to the host occurs, where the handle_sve() fallback path
reflects an undefined instruction exception back to the guest,
consistently with the behaviour of non-SVE-capable hardware (as was
done unconditionally prior to this patch).

No SVE handling is added on non-VHE-only paths, since VHE is an
architectural and Kconfig prerequisite of SVE.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch adds the necessary support for context switching ZCR_EL1
for each vcpu.

ZCR_EL1 is trapped alongside the FPSIMD/SVE registers, so it makes
sense for it to be handled as part of the guest FPSIMD/SVE context
for context switch purposes instead of handling it as a general
system register.  This means that it can be switched in lazily at
the appropriate time.  No effort is made to track host context for
this register, since SVE requires VHE: thus the hosts's value for
this register lives permanently in ZCR_EL2 and does not alias the
guest's value at any time.

The Hyp switch and fpsimd context handling code is extended
appropriately.

Accessors are added in sys_regs.c to expose the SVE system
registers and ID register fields.  Because these need to be
conditionally visible based on the guest configuration, they are
implemented separately for now rather than by use of the generic
system register helpers.  This may be abstracted better later on
when/if there are more features requiring this model.

ID_AA64ZFR0_EL1 is RO-RAZ for MRS/MSR when SVE is disabled for the
guest, but for compatibility with non-SVE aware KVM implementations
the register should not be enumerated at all for KVM_GET_REG_LIST
in this case.  For consistency we also reject ioctl access to the
register.  This ensures that a non-SVE-enabled guest looks the same
to userspace, irrespective of whether the kernel KVM implementation
supports SVE.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Some optional features of the Arm architecture add new system
registers that are not present in the base architecture.

Where these features are optional for the guest, the visibility of
these registers may need to depend on some runtime configuration,
such as a flag passed to KVM_ARM_VCPU_INIT.

For example, ZCR_EL1 and ID_AA64ZFR0_EL1 need to be hidden if SVE
is not enabled for the guest, even though these registers may be
present in the hardware and visible to the host at EL2.

Adding special-case checks all over the place for individual
registers is going to get messy as the number of conditionally-
visible registers grows.

In order to help solve this problem, this patch adds a new sysreg
method visibility() that can be used to hook in any needed runtime
visibility checks.  This method can currently return
REG_HIDDEN_USER to inhibit enumeration and ioctl access to the
register for userspace, and REG_HIDDEN_GUEST to inhibit runtime
access by the guest using MSR/MRS.  Wrappers are added to allow
these flags to be conveniently queried.

This approach allows a conditionally modified view of individual
system registers such as the CPU ID registers, in addition to
completely hiding register where appropriate.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Architecture features that are conditionally visible to the guest
will require run-time checks in the ID register accessor functions.
In particular, read_id_reg() will need to perform checks in order
to generate the correct emulated value for certain ID register
fields such as ID_AA64PFR0_EL1.SVE for example.

This patch propagates vcpu into read_id_reg() so that future
patches can add run-time checks on the guest configuration here.

For now, there is no functional change.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Since SVE will be enabled or disabled on a per-vcpu basis, a flag
is needed in order to track which vcpus have it enabled.

This patch adds a suitable flag and a helper for checking it.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The current FPSIMD/SVE context handling support for non-task (i.e.,
KVM vcpu) contexts does not take SVE into account.  This means that
only task contexts can safely use SVE at present.

In preparation for enabling KVM guests to use SVE, it is necessary
to keep track of SVE state for non-task contexts too.

This patch adds the necessary support, removing assumptions from
the context switch code about the location of the SVE context
storage.

When binding a vcpu context, its vector length is arbitrarily
specified as SVE_VL_MIN for now.  In any case, because TIF_SVE is
presently cleared at vcpu context bind time, the specified vector
length will not be used for anything yet.  In later patches TIF_SVE
will be set here as appropriate, and the appropriate maximum vector
length for the vcpu will be passed when binding.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Due to the way the effective SVE vector length is controlled and
trapped at different exception levels, certain mismatches in the
sets of vector lengths supported by different physical CPUs in the
system may prevent straightforward virtualisation of SVE at parity
with the host.

This patch analyses the extent to which SVE can be virtualised
safely without interfering with migration of vcpus between physical
CPUs, and rejects late secondary CPUs that would erode the
situation further.

It is left up to KVM to decide what to do with this information.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

The roles of sve_init_vq_map(), sve_update_vq_map() and
sve_verify_vq_map() are highly non-obvious to anyone who has not dug
through cpufeatures.c in detail.

Since the way these functions interact with each other is more
important here than a full understanding of the cpufeatures code, this
patch adds comments to make the functions' roles clearer.

No functional change.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Thierry <julien.thierry@arm.com>
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

kvm_host.h uses some declarations from other headers that are
currently included by accident, without an explicit #include.

This patch adds a few #includes that are clearly missing.  Although
the header builds without them today, this should help to avoid
future surprises.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

kvm_arm_num_regs() adds together various partial register counts in
a freeform sum expression, which makes it harder than necessary to
read diffs that add, modify or remove a single term in the sum
(which is expected to the common case under maintenance).

This patch refactors the code to add the term one per line, for
maximum readability.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

__fpsimd_enabled() no longer exists, but a dangling declaration has
survived in kvm_hyp.h.

This patch gets rid of it.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

This patch updates fpsimd_flush_task_state() to mirror the new
semantics of fpsimd_flush_cpu_state() introduced by commit
d8ad71fa ("arm64: fpsimd: Fix TIF_FOREIGN_FPSTATE after
invalidating cpu regs").  Both functions now implicitly set
TIF_FOREIGN_FPSTATE to indicate that the task's FPSIMD state is not
loaded into the cpu.

As a side-effect, fpsimd_flush_task_state() now sets
TIF_FOREIGN_FPSTATE even for non-running tasks.  In the case of
non-running tasks this is not useful but also harmless, because the
flag is live only while the corresponding task is running.  This
function is not called from fast paths, so special-casing this for
the task == current case is not really worth it.

Compiler barriers previously present in restore_sve_fpsimd_context()
are pulled into fpsimd_flush_task_state() so that it can be safely
called with preemption enabled if necessary.

Explicit calls to set TIF_FOREIGN_FPSTATE that accompany
fpsimd_flush_task_state() calls and are now redundant are removed
as appropriate.

fpsimd_flush_task_state() is used to get exclusive access to the
representation of the task's state via task_struct, for the purpose
of replacing the state.  Thus, the call to this function should
happen before manipulating fpsimd_state or sve_state etc. in
task_struct.  Anomalous cases are reordered appropriately in order
to make the code more consistent, although there should be no
functional difference since these cases are protected by
local_bh_disable() anyway.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Tested-by: Nzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Since the the sizes of individual members of the core arm64
registers vary, the list of register encodings that make sense is
not a simple linear sequence.

To clarify which encodings to use, this patch adds a brief list
to the documentation.
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Pull ext4 fixes from Ted Ts'o:
 "Miscellaneous ext4 bug fixes for 5.1"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: prohibit fstrim in norecovery mode
  ext4: cleanup bh release code in ext4_ind_remove_space()
  ext4: brelse all indirect buffer in ext4_ind_remove_space()
  ext4: report real fs size after failed resize
  ext4: add missing brelse() in add_new_gdb_meta_bg()
  ext4: remove useless ext4_pin_inode()
  ext4: avoid panic during forced reboot
  ext4: fix data corruption caused by unaligned direct AIO
  ext4: fix NULL pointer dereference while journal is aborted

Pull scheduler updates from Thomas Gleixner:
 "Third more careful attempt for this set of fixes:

   - Prevent a 32bit math overflow in the cpufreq code

   - Fix a buffer overflow when scanning the cgroup2 cpu.max property

   - A set of fixes for the NOHZ scheduler logic to prevent waking up
     CPUs even if the capacity of the busy CPUs is sufficient along with
     other tweaks optimizing the behaviour for asymmetric systems
     (big/little)"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Skip LLC NOHZ logic for asymmetric systems
  sched/fair: Tune down misfit NOHZ kicks
  sched/fair: Comment some nohz_balancer_kick() kick conditions
  sched/core: Fix buffer overflow in cgroup2 property cpu.max
  sched/cpufreq: Fix 32-bit math overflow

Pull perf updates from Thomas Gleixner:
 "A larger set of perf updates.

  Not all of them are strictly fixes, but that's solely the tip
  maintainers fault as they let the timely -rc1 pull request fall
  through the cracks for various reasons including travel. So I'm
  sending this nevertheless because rebasing and distangling fixes and
  updates would be a mess and risky as well. As of tomorrow, a strict
  fixes separation is happening again. Sorry for the slip-up.

  Kernel:

   - Handle RECORD_MMAP vs. RECORD_MMAP2 correctly so different
     consumers of the mmap event get what they requested.

  Tools:

   - A larger set of updates to perf record/report/scripts vs. time
     stamp handling

   - More Python3 fixups

   - A pile of memory leak plumbing

   - perf BPF improvements and fixes

   - Finalize the perf.data directory storage"

[ Note: the kernel part is strictly a fix, the updates are purely to
  tooling       - Linus ]

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
  perf bpf: Show more BPF program info in print_bpf_prog_info()
  perf bpf: Extract logic to create program names from perf_event__synthesize_one_bpf_prog()
  perf tools: Save bpf_prog_info and BTF of new BPF programs
  perf evlist: Introduce side band thread
  perf annotate: Enable annotation of BPF programs
  perf build: Check what binutils's 'disassembler()' signature to use
  perf bpf: Process PERF_BPF_EVENT_PROG_LOAD for annotation
  perf symbols: Introduce DSO_BINARY_TYPE__BPF_PROG_INFO
  perf feature detection: Add -lopcodes to feature-libbfd
  perf top: Add option --no-bpf-event
  perf bpf: Save BTF information as headers to perf.data
  perf bpf: Save BTF in a rbtree in perf_env
  perf bpf: Save bpf_prog_info information as headers to perf.data
  perf bpf: Save bpf_prog_info in a rbtree in perf_env
  perf bpf: Make synthesize_bpf_events() receive perf_session pointer instead of perf_tool
  perf bpf: Synthesize bpf events with bpf_program__get_prog_info_linear()
  bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()
  tools lib bpf: Introduce bpf_program__get_prog_info_linear()
  perf record: Replace option --bpf-event with --no-bpf-event
  perf tests: Fix a memory leak in test__perf_evsel__tp_sched_test()
  ...