* kvm-arm64/misc:
: Miscellaneous updates
:
: - Drop useless check against vgic state in ICC_CLTR_EL1.SEIS read
: emulation
:
: - Fix trap configuration for pKVM
:
: - Close the door on initialization bugs surrounding userspace irqchip
: static key by removing it.
KVM: selftests: Don't bother deleting memslots in KVM when freeing VMs
KVM: arm64: Get rid of userspace_irqchip_in_use
KVM: arm64: Initialize trap register values in hyp in pKVM
KVM: arm64: Initialize the hypervisor's VM state at EL2
KVM: arm64: Refactor kvm_vcpu_enable_ptrauth() for hyp use
KVM: arm64: Move pkvm_vcpu_init_traps() to init_pkvm_hyp_vcpu()
KVM: arm64: Don't map 'kvm_vgic_global_state' at EL2 with pKVM
KVM: arm64: Just advertise SEIS as 0 when emulating ICC_CTLR_EL1
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Improper use of userspace_irqchip_in_use led to syzbot hitting the
following WARN_ON() in kvm_timer_update_irq():
WARNING: CPU: 0 PID: 3281 at arch/arm64/kvm/arch_timer.c:459
kvm_timer_update_irq+0x21c/0x394
Call trace:
kvm_timer_update_irq+0x21c/0x394 arch/arm64/kvm/arch_timer.c:459
kvm_timer_vcpu_reset+0x158/0x684 arch/arm64/kvm/arch_timer.c:968
kvm_reset_vcpu+0x3b4/0x560 arch/arm64/kvm/reset.c:264
kvm_vcpu_set_target arch/arm64/kvm/arm.c:1553 [inline]
kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1573 [inline]
kvm_arch_vcpu_ioctl+0x112c/0x1b3c arch/arm64/kvm/arm.c:1695
kvm_vcpu_ioctl+0x4ec/0xf74 virt/kvm/kvm_main.c:4658
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__arm64_sys_ioctl+0x108/0x184 fs/ioctl.c:893
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x78/0x1b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x1b0 arch/arm64/kernel/syscall.c:132
do_el0_svc+0x40/0x50 arch/arm64/kernel/syscall.c:151
el0_svc+0x54/0x14c arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
The following sequence led to the scenario:
- Userspace creates a VM and a vCPU.
- The vCPU is initialized with KVM_ARM_VCPU_PMU_V3 during
KVM_ARM_VCPU_INIT.
- Without any other setup, such as vGIC or vPMU, userspace issues
KVM_RUN on the vCPU. Since the vPMU is requested, but not setup,
kvm_arm_pmu_v3_enable() fails in kvm_arch_vcpu_run_pid_change().
As a result, KVM_RUN returns after enabling the timer, but before
incrementing 'userspace_irqchip_in_use':
kvm_arch_vcpu_run_pid_change()
ret = kvm_arm_pmu_v3_enable()
if (!vcpu->arch.pmu.created)
return -EINVAL;
if (ret)
return ret;
[...]
if (!irqchip_in_kernel(kvm))
static_branch_inc(&userspace_irqchip_in_use);
- Userspace ignores the error and issues KVM_ARM_VCPU_INIT again.
Since the timer is already enabled, control moves through the
following flow, ultimately hitting the WARN_ON():
kvm_timer_vcpu_reset()
if (timer->enabled)
kvm_timer_update_irq()
if (!userspace_irqchip())
ret = kvm_vgic_inject_irq()
ret = vgic_lazy_init()
if (unlikely(!vgic_initialized(kvm)))
if (kvm->arch.vgic.vgic_model !=
KVM_DEV_TYPE_ARM_VGIC_V2)
return -EBUSY;
WARN_ON(ret);
Theoretically, since userspace_irqchip_in_use's functionality can be
simply replaced by '!irqchip_in_kernel()', get rid of the static key
to avoid the mismanagement, which also helps with the syzbot issue.
Cc: <stable@vger.kernel.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Move pkvm_vcpu_init_traps() to the initialization of the
hypervisor's vcpu state in init_pkvm_hyp_vcpu(), and remove the
associated hypercall.
In protected mode, traps need to be initialized whenever a VCPU
is initialized anyway, and not only for protected VMs. This also
saves an unnecessary hypercall.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241018074833.2563674-2-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
As there is very little ordering in the KVM API, userspace can
instanciate a half-baked GIC (missing its memory map, for example)
at almost any time.
This means that, with the right timing, a thread running vcpu-0
can enter the kernel without a GIC configured and get a GIC created
behind its back by another thread. Amusingly, it will pick up
that GIC and start messing with the data structures without the
GIC having been fully initialised.
Similarly, a thread running vcpu-1 can enter the kernel, and try
to init the GIC that was previously created. Since this GIC isn't
properly configured (no memory map), it fails to correctly initialise.
And that's the point where we decide to teardown the GIC, freeing all
its resources. Behind vcpu-0's back. Things stop pretty abruptly,
with a variety of symptoms. Clearly, this isn't good, we should be
a bit more careful about this.
It is obvious that this guest is not viable, as it is missing some
important part of its configuration. So instead of trying to tear
bits of it down, let's just mark it as *dead*. It means that any
further interaction from userspace will result in -EIO. The memory
will be released on the "normal" path, when userspace gives up.
Cc: stable@vger.kernel.org
Reported-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241009183603.3221824-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
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>
Register KVM's cpuhp and syscore callbacks when enabling virtualization in
hardware, as the sole purpose of said callbacks is to disable and re-enable
virtualization as needed.
The primary motivation for this series is to simplify dealing with enabling
virtualization for Intel's TDX, which needs to enable virtualization
when kvm-intel.ko is loaded, i.e. long before the first VM is created.
That said, this is a nice cleanup on its own. By registering the callbacks
on-demand, the callbacks themselves don't need to check kvm_usage_count,
because their very existence implies a non-zero count.
Patch 1 (re)adds a dedicated lock for kvm_usage_count. This avoids a
lock ordering issue between cpus_read_lock() and kvm_lock. The lock
ordering issue still exist in very rare cases, and will be fixed for
good by switching vm_list to an (S)RCU-protected list.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm-arm64/s2-ptdump:
: .
: Stage-2 page table dumper, reusing the main ptdump infrastructure,
: courtesy of Sebastian Ene. From the cover letter:
:
: "This series extends the ptdump support to allow dumping the guest
: stage-2 pagetables. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump
: registers the new following files under debugfs:
: - /sys/debug/kvm/<guest_id>/stage2_page_tables
: - /sys/debug/kvm/<guest_id>/stage2_levels
: - /sys/debug/kvm/<guest_id>/ipa_range
:
: This allows userspace tools (eg. cat) to dump the stage-2 pagetables by
: reading the 'stage2_page_tables' file.
: [...]"
: .
KVM: arm64: Register ptdump with debugfs on guest creation
arm64: ptdump: Don't override the level when operating on the stage-2 tables
arm64: ptdump: Use the ptdump description from a local context
arm64: ptdump: Expose the attribute parsing functionality
KVM: arm64: Move pagetable definitions to common header
Signed-off-by: Marc Zyngier <maz@kernel.org>
While arch/*/mem/ptdump handles the kernel pagetable dumping code,
introduce KVM/ptdump to show the guest stage-2 pagetables. The
separation is necessary because most of the definitions from the
stage-2 pagetable reside in the KVM path and we will be invoking
functionality specific to KVM. Introduce the PTDUMP_STAGE2_DEBUGFS config.
When a guest is created, register a new file entry under the guest
debugfs dir which allows userspace to show the contents of the guest
stage-2 pagetables when accessed.
[maz: moved function prototypes from kvm_host.h to kvm_mmu.h]
Signed-off-by: Sebastian Ene <sebastianene@google.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20240909124721.1672199-6-sebastianene@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Rename the per-CPU hooks used to enable virtualization in hardware to
align with the KVM-wide helpers in kvm_main.c, and to better capture that
the callbacks are invoked on every online CPU.
No functional change intended.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-ID: <20240830043600.127750-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We already have to perform a set of last-chance adjustments for
NV purposes. We will soon have to do the same for the GIC, so
introduce a helper for that exact purpose.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-5-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tidy up some of the PAuth trapping code to clear up some comments
and avoid clang/checkpatch warnings. Also, don't bother setting
PAuth HCR_EL2 bits in pKVM, since it's handled by the hypervisor.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20240722163311.1493879-1-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Fix kdoc warnings by adding missing function parameter
descriptions or by conversion to a normal comment.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240723101204.7356-3-sebott@redhat.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
- Enable halt poll shrinking by default, as Intel found it to be a clear win.
- Setup empty IRQ routing when creating a VM to avoid having to synchronize
SRCU when creating a split IRQCHIP on x86.
- Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
that arch code can use for hooking both sched_in() and sched_out().
- Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
truncating a bogus value from userspace, e.g. to help userspace detect bugs.
- Mark a vCPU as preempted if and only if it's scheduled out while in the
KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
memory when retrieving guest state during live migration blackout.
- A few minor cleanups
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Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEAD
KVM generic changes for 6.11
- Enable halt poll shrinking by default, as Intel found it to be a clear win.
- Setup empty IRQ routing when creating a VM to avoid having to synchronize
SRCU when creating a split IRQCHIP on x86.
- Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
that arch code can use for hooking both sched_in() and sched_out().
- Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
truncating a bogus value from userspace, e.g. to help userspace detect bugs.
- Mark a vCPU as preempted if and only if it's scheduled out while in the
KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
memory when retrieving guest state during live migration blackout.
- A few minor cleanups
* 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>
* kvm-arm64/ctr-el0:
: Support for user changes to CTR_EL0, courtesy of Sebastian Ott
:
: Allow userspace to change the guest-visible value of CTR_EL0 for a VM,
: so long as the requested value represents a subset of features supported
: by hardware. In other words, prevent the VMM from over-promising the
: capabilities of hardware.
:
: Make this happen by fitting CTR_EL0 into the existing infrastructure for
: feature ID registers.
KVM: selftests: Assert that MPIDR_EL1 is unchanged across vCPU reset
KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking
KVM: selftests: arm64: Test writes to CTR_EL0
KVM: arm64: rename functions for invariant sys regs
KVM: arm64: show writable masks for feature registers
KVM: arm64: Treat CTR_EL0 as a VM feature ID register
KVM: arm64: unify code to prepare traps
KVM: arm64: nv: Use accessors for modifying ID registers
KVM: arm64: Add helper for writing ID regs
KVM: arm64: Use read-only helper for reading VM ID registers
KVM: arm64: Make idregs debugfs iterator search sysreg table directly
KVM: arm64: Get sys_reg encoding from descriptor in idregs_debug_show()
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/shadow-mmu:
: Shadow stage-2 MMU support for NV, courtesy of Marc Zyngier
:
: Initial implementation of shadow stage-2 page tables to support a guest
: hypervisor. In the author's words:
:
: So here's the 10000m (approximately 30000ft for those of you stuck
: with the wrong units) view of what this is doing:
:
: - for each {VMID,VTTBR,VTCR} tuple the guest uses, we use a
: separate shadow s2_mmu context. This context has its own "real"
: VMID and a set of page tables that are the combination of the
: guest's S2 and the host S2, built dynamically one fault at a time.
:
: - these shadow S2 contexts are ephemeral, and behave exactly as
: TLBs. For all intent and purposes, they *are* TLBs, and we discard
: them pretty often.
:
: - TLB invalidation takes three possible paths:
:
: * either this is an EL2 S1 invalidation, and we directly emulate
: it as early as possible
:
: * or this is an EL1 S1 invalidation, and we need to apply it to
: the shadow S2s (plural!) that match the VMID set by the L1 guest
:
: * or finally, this is affecting S2, and we need to teardown the
: corresponding part of the shadow S2s, which invalidates the TLBs
KVM: arm64: nv: Truely enable nXS TLBI operations
KVM: arm64: nv: Add handling of NXS-flavoured TLBI operations
KVM: arm64: nv: Add handling of range-based TLBI operations
KVM: arm64: nv: Add handling of outer-shareable TLBI operations
KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information
KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level
KVM: arm64: nv: Handle FEAT_TTL hinted TLB operations
KVM: arm64: nv: Handle TLBI IPAS2E1{,IS} operations
KVM: arm64: nv: Handle TLBI ALLE1{,IS} operations
KVM: arm64: nv: Handle TLBI VMALLS12E1{,IS} operations
KVM: arm64: nv: Handle TLB invalidation targeting L2 stage-1
KVM: arm64: nv: Handle EL2 Stage-1 TLB invalidation
KVM: arm64: nv: Add Stage-1 EL2 invalidation primitives
KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
KVM: arm64: nv: Handle shadow stage 2 page faults
KVM: arm64: nv: Implement nested Stage-2 page table walk logic
KVM: arm64: nv: Support multiple nested Stage-2 mmu structures
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
There are 2 functions to calculate traps via HCR_EL2:
* kvm_init_sysreg() called via KVM_RUN (before the 1st run or when
the pid changes)
* vcpu_reset_hcr() called via KVM_ARM_VCPU_INIT
To unify these 2 and to support traps that are dependent on the
ID register configuration, move the code from vcpu_reset_hcr()
to sys_regs.c and call it via kvm_init_sysreg().
We still have to keep the non-FWB handling stuff in vcpu_reset_hcr().
Also the initialization with HCR_GUEST_FLAGS is kept there but guarded
by !vcpu_has_run_once() to ensure that previous calculated values
don't get overwritten.
While at it rename kvm_init_sysreg() to kvm_calculate_traps() to
better reflect what it's doing.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20240619174036.483943-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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>
Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run
loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit
was not set.
Replace all references to vcpu->run->immediate_exit with
!vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a
malicious userspace could invoked KVM_RUN with immediate_exit=true and
then after KVM reads it to set wants_to_run=false, flip it to false.
This would result in the vCPU running in KVM_RUN with
wants_to_run=false. This wouldn't cause any real bugs today but is a
dangerous landmine.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add an early_params to control WFI and WFE trapping. This is to
control the degree guests can wait for interrupts on their own without
being trapped by KVM. Options for each param are trap and notrap. trap
enables the trap. notrap disables the trap. Note that when enabled,
traps are allowed but not guaranteed by the CPU architecture. Absent
an explicitly set policy, default to current behavior: disabling the
trap if only a single task is running and enabling otherwise.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20240523174056.1565133-1-coltonlewis@google.com
[ oliver: rework kvm_vcpu_should_clear_tw*() for readability ]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Now that we have introduced finalize_init_hyp_mode(), lets
consolidate the initializing of the host_data fpsimd_state and
sve state.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240603122852.3923848-8-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Protected mode needs to maintain (save/restore) the host's sve
state, rather than relying on the host kernel to do that. This is
to avoid leaking information to the host about guests and the
type of operations they are performing.
As a first step towards that, allocate memory mapped at hyp, per
cpu, for the host sve state. The following patch will use this
memory to save/restore the host state.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20240603122852.3923848-6-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/mpidr-reset:
: .
: Fixes for CLIDR_EL1 and MPIDR_EL1 being accidentally mutable across
: a vcpu reset, courtesy of Oliver. From the cover letter:
:
: "For VM-wide feature ID registers we ensure they get initialized once for
: the lifetime of a VM. On the other hand, vCPU-local feature ID registers
: get re-initialized on every vCPU reset, potentially clobbering the
: values userspace set up.
:
: MPIDR_EL1 and CLIDR_EL1 are the only registers in this space that we
: allow userspace to modify for now. Clobbering the value of MPIDR_EL1 has
: some disastrous side effects as the compressed index used by the
: MPIDR-to-vCPU lookup table assumes MPIDR_EL1 is immutable after KVM_RUN.
:
: Series + reproducer test case to address the problem of KVM wiping out
: userspace changes to these registers. Note that there are still some
: differences between VM and vCPU scoped feature ID registers from the
: perspective of userspace. We do not allow the value of VM-scope
: registers to change after KVM_RUN, but vCPU registers remain mutable."
: .
KVM: selftests: arm64: Test vCPU-scoped feature ID registers
KVM: selftests: arm64: Test that feature ID regs survive a reset
KVM: selftests: arm64: Store expected register value in set_id_regs
KVM: selftests: arm64: Rename helper in set_id_regs to imply VM scope
KVM: arm64: Only reset vCPU-scoped feature ID regs once
KVM: arm64: Reset VM feature ID regs from kvm_reset_sys_regs()
KVM: arm64: Rename is_id_reg() to imply VM scope
Signed-off-by: Marc Zyngier <maz@kernel.org>
The general expecation with feature ID registers is that they're 'reset'
exactly once by KVM for the lifetime of a vCPU/VM, such that any
userspace changes to the CPU features / identity are honored after a
vCPU gets reset (e.g. PSCI_ON).
KVM handles what it calls VM-scoped feature ID registers correctly, but
feature ID registers local to a vCPU (CLIDR_EL1, MPIDR_EL1) get wiped
after every reset. What's especially concerning is that a
potentially-changing MPIDR_EL1 breaks MPIDR compression for indexing
mpidr_data, as the mask of useful bits to build the index could change.
This is absolutely no good. Avoid resetting vCPU feature ID registers
more than once.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240502233529.1958459-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/misc-6.10:
: .
: Misc fixes and updates targeting 6.10
:
: - Improve boot-time diagnostics when the sysreg tables
: are not correctly sorted
:
: - Allow FFA_MSG_SEND_DIRECT_REQ in the FFA proxy
:
: - Fix duplicate XNX field in the ID_AA64MMFR1_EL1
: writeable mask
:
: - Allocate PPIs and SGIs outside of the vcpu structure, allowing
: for smaller EL2 mapping and some flexibility in implementing
: more or less than 32 private IRQs.
:
: - Use bitmap_gather() instead of its open-coded equivalent
:
: - Make protected mode use hVHE if available
:
: - Purge stale mpidr_data if a vcpu is created after the MPIDR
: map has been created
: .
KVM: arm64: Destroy mpidr_data for 'late' vCPU creation
KVM: arm64: Use hVHE in pKVM by default on CPUs with VHE support
KVM: arm64: Fix hvhe/nvhe early alias parsing
KVM: arm64: Convert kvm_mpidr_index() to bitmap_gather()
KVM: arm64: vgic: Allocate private interrupts on demand
KVM: arm64: Remove duplicated AA64MMFR1_EL1 XNX
KVM: arm64: Remove FFA_MSG_SEND_DIRECT_REQ from the denylist
KVM: arm64: Improve out-of-order sysreg table diagnostics
Signed-off-by: Marc Zyngier <maz@kernel.org>
A particularly annoying userspace could create a vCPU after KVM has
computed mpidr_data for the VM, either by racing against VGIC
initialization or having a userspace irqchip.
In any case, this means mpidr_data no longer fully describes the VM, and
attempts to find the new vCPU with kvm_mpidr_to_vcpu() will fail. The
fix is to discard mpidr_data altogether, as it is only a performance
optimization and not required for correctness. In all likelihood KVM
will recompute the mappings when KVM_RUN is called on the new vCPU.
Note that reads of mpidr_data are not guarded by a lock; promote to RCU
to cope with the possibility of mpidr_data being invalidated at runtime.
Fixes: 54a8006d0b ("KVM: arm64: Fast-track kvm_mpidr_to_vcpu() when mpidr_data is available")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240508071952.2035422-1-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/pkvm-6.10: (25 commits)
: .
: At last, a bunch of pKVM patches, courtesy of Fuad Tabba.
: From the cover letter:
:
: "This series is a bit of a bombay-mix of patches we've been
: carrying. There's no one overarching theme, but they do improve
: the code by fixing existing bugs in pKVM, refactoring code to
: make it more readable and easier to re-use for pKVM, or adding
: functionality to the existing pKVM code upstream."
: .
KVM: arm64: Force injection of a data abort on NISV MMIO exit
KVM: arm64: Restrict supported capabilities for protected VMs
KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap()
KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst
KVM: arm64: Rename firmware pseudo-register documentation file
KVM: arm64: Reformat/beautify PTP hypercall documentation
KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit
KVM: arm64: Introduce and use predicates that check for protected VMs
KVM: arm64: Add is_pkvm_initialized() helper
KVM: arm64: Simplify vgic-v3 hypercalls
KVM: arm64: Move setting the page as dirty out of the critical section
KVM: arm64: Change kvm_handle_mmio_return() return polarity
KVM: arm64: Fix comment for __pkvm_vcpu_init_traps()
KVM: arm64: Prevent kmemleak from accessing .hyp.data
KVM: arm64: Do not map the host fpsimd state to hyp in pKVM
KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE
KVM: arm64: Support TLB invalidation in guest context
KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE
KVM: arm64: Check for PTE validity when checking for executable/cacheable
KVM: arm64: Avoid BUG-ing from the host abort path
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/nv-eret-pauth:
: .
: Add NV support for the ERETAA/ERETAB instructions. From the cover letter:
:
: "Although the current upstream NV support has *some* support for
: correctly emulating ERET, that support is only partial as it doesn't
: support the ERETAA and ERETAB variants.
:
: Supporting these instructions was cast aside for a long time as it
: involves implementing some form of PAuth emulation, something I wasn't
: overly keen on. But I have reached a point where enough of the
: infrastructure is there that it actually makes sense. So here it is!"
: .
KVM: arm64: nv: Work around lack of pauth support in old toolchains
KVM: arm64: Drop trapping of PAuth instructions/keys
KVM: arm64: nv: Advertise support for PAuth
KVM: arm64: nv: Handle ERETA[AB] instructions
KVM: arm64: nv: Add emulation for ERETAx instructions
KVM: arm64: nv: Add kvm_has_pauth() helper
KVM: arm64: nv: Reinject PAC exceptions caused by HCR_EL2.API==0
KVM: arm64: nv: Handle HCR_EL2.{API,APK} independently
KVM: arm64: nv: Honor HFGITR_EL2.ERET being set
KVM: arm64: nv: Fast-track 'InHost' exception returns
KVM: arm64: nv: Add trap forwarding for ERET and SMC
KVM: arm64: nv: Configure HCR_EL2 for FEAT_NV2
KVM: arm64: nv: Drop VCPU_HYP_CONTEXT flag
KVM: arm64: Constraint PAuth support to consistent implementations
KVM: arm64: Add helpers for ESR_ELx_ERET_ISS_ERET*
KVM: arm64: Harden __ctxt_sys_reg() against out-of-range values
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/host_data:
: .
: Rationalise the host-specific data to live as part of the per-CPU state.
:
: From the cover letter:
:
: "It appears that over the years, we have accumulated a lot of cruft in
: the kvm_vcpu_arch structure. Part of the gunk is data that is strictly
: host CPU specific, and this result in two main problems:
:
: - the structure itself is stupidly large, over 8kB. With the
: arch-agnostic kvm_vcpu, we're above 10kB, which is insane. This has
: some ripple effects, as we need physically contiguous allocation to
: be able to map it at EL2 for !VHE. There is more to it though, as
: some data structures, although per-vcpu, could be allocated
: separately.
:
: - We lose track of the life-cycle of this data, because we're
: guaranteed that it will be around forever and we start relying on
: wrong assumptions. This is becoming a maintenance burden.
:
: This series rectifies some of these things, starting with the two main
: offenders: debug and FP, a lot of which gets pushed out to the per-CPU
: host structure. Indeed, their lifetime really isn't that of the vcpu,
: but tied to the physical CPU the vpcu runs on.
:
: This results in a small reduction of the vcpu size, but mainly a much
: clearer understanding of the life-cycle of these structures."
: .
KVM: arm64: Move management of __hyp_running_vcpu to load/put on VHE
KVM: arm64: Exclude FP ownership from kvm_vcpu_arch
KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch
KVM: arm64: Exclude mdcr_el2_host from kvm_vcpu_arch
KVM: arm64: Exclude host_debug_data from vcpu_arch
KVM: arm64: Add accessor for per-CPU state
Signed-off-by: Marc Zyngier <maz@kernel.org>
For practical reasons as well as security related ones, not all
capabilities are supported for protected VMs in pKVM.
Add a function that restricts the capabilities for protected VMs.
This behaves as an allow-list to ensure that future capabilities
are checked for compatibility and security before being allowed
for protected VMs.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-30-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Initialize r = -EINVAL to get rid of the error-path
initializations in kvm_vm_ioctl_enable_cap().
No functional change intended.
Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-29-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Consolidate the GICv3 VMCR accessor hypercalls into the APR save/restore
hypercalls so that all of the EL2 GICv3 state is covered by a single pair
of hypercalls.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-17-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Most exit handlers return <= 0 to indicate that the host needs to
handle the exit. Make kvm_handle_mmio_return() consistent with
the exit handlers in handle_exit(). This makes the code easier to
reason about, and makes it easier to add other handlers in future
patches.
No functional change intended.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-15-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
We currently insist on disabling PAuth on vcpu_load(), and get to
enable it on first guest use of an instruction or a key (ignoring
the NV case for now).
It isn't clear at all what this is trying to achieve: guests tend
to use PAuth when available, and nothing forces you to expose it
to the guest if you don't want to. This also isn't totally free:
we take a full GPR save/restore between host and guest, only to
write ten 64bit registers. The "value proposition" escapes me.
So let's forget this stuff and enable PAuth eagerly if exposed to
the guest. This results in much simpler code. Performance wise,
that's not bad either (tested on M2 Pro running a fully automated
Debian installer as the workload):
- On a non-NV guest, I can see reduction of 0.24% in the number
of cycles (measured with perf over 10 consecutive runs)
- On a NV guest (L2), I see a 2% reduction in wall-clock time
(measured with 'time', as M2 doesn't have a PMUv3 and NV
doesn't support it either)
So overall, a much reduced complexity and a (small) performance
improvement.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-16-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
PAuth comes it two parts: address authentication, and generic
authentication. So far, KVM mandates that both are implemented.
PAuth also comes in three flavours: Q5, Q3, and IMPDEF. Only one
can be implemented for any of address and generic authentication.
Crucially, the architecture doesn't mandate that address and generic
authentication implement the *same* flavour. This would make
implementing ERETAx very difficult for NV, something we are not
terribly keen on.
So only allow PAuth support for KVM on systems that are not totally
insane. Which is so far 100% of the known HW.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-4-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
In retrospect, it is fairly obvious that the FP state ownership
is only meaningful for a given CPU, and that locating this
information in the vcpu was just a mistake.
Move the ownership tracking into the host data structure, and
rename it from fp_state to fp_owner, which is a better description
(name suggested by Mark Brown).
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to facilitate the introduction of new per-CPU state,
add a new host_data_ptr() helped that hides some of the per-CPU
verbosity, and make it easier to move that state around in the
future.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
We are not very consistent when it comes to displaying which mode
we're in (VHE, {n,h}VHE, protected or not). For example, booting
in protected mode with hVHE results in:
[ 0.969545] kvm [1]: Protected nVHE mode initialized successfully
which is mildly amusing considering that the machine is VHE only.
We already cleaned this up a bit with commit 1f3ca7023f ("KVM:
arm64: print Hyp mode"), but that's still unsatisfactory.
Unify the three strings into one and use a mess of conditional
statements to sort it out (yes, it's a slow day).
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240321173706.3280796-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/vm-configuration: (29 commits)
: VM configuration enforcement, courtesy of Marc Zyngier
:
: Userspace has gained the ability to control the features visible
: through the ID registers, yet KVM didn't take this into account as the
: effective feature set when determing trap / emulation behavior. This
: series adds:
:
: - Mechanism for testing the presence of a particular CPU feature in the
: guest's ID registers
:
: - Infrastructure for computing the effective value of VNCR-backed
: registers, taking into account the RES0 / RES1 bits for a particular
: VM configuration
:
: - Implementation of 'fine-grained UNDEF' controls that shadow the FGT
: register definitions.
KVM: arm64: Don't initialize idreg debugfs w/ preemption disabled
KVM: arm64: Fail the idreg iterator if idregs aren't initialized
KVM: arm64: Make build-time check of RES0/RES1 bits optional
KVM: arm64: Add debugfs file for guest's ID registers
KVM: arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later checking
KVM: arm64: Make FEAT_MOPS UNDEF if not advertised to the guest
KVM: arm64: Make AMU sysreg UNDEF if FEAT_AMU is not advertised to the guest
KVM: arm64: Make PIR{,E0}_EL1 UNDEF if S1PIE is not advertised to the guest
KVM: arm64: Make TLBI OS/Range UNDEF if not advertised to the guest
KVM: arm64: Streamline save/restore of HFG[RW]TR_EL2
KVM: arm64: Move existing feature disabling over to FGU infrastructure
KVM: arm64: Propagate and handle Fine-Grained UNDEF bits
KVM: arm64: Add Fine-Grained UNDEF tracking information
KVM: arm64: Rename __check_nv_sr_forward() to triage_sysreg_trap()
KVM: arm64: Use the xarray as the primary sysreg/sysinsn walker
KVM: arm64: Register AArch64 system register entries with the sysreg xarray
KVM: arm64: Always populate the trap configuration xarray
KVM: arm64: nv: Move system instructions to their own sys_reg_desc array
KVM: arm64: Drop the requirement for XARRAY_MULTI
KVM: arm64: nv: Turn encoding ranges into discrete XArray stores
...
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Testing KVM with DEBUG_ATOMIC_SLEEP enabled doesn't get far before hitting the
first splat:
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 13062, name: vgic_lpi_stress
preempt_count: 1, expected: 0
2 locks held by vgic_lpi_stress/13062:
#0: ffff080084553240 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xc0/0x13f0
#1: ffff800080485f08 (&kvm->arch.config_lock){+.+.}-{3:3}, at: kvm_arch_vcpu_ioctl+0xd60/0x1788
CPU: 19 PID: 13062 Comm: vgic_lpi_stress Tainted: G W O 6.8.0-dbg-DEV #1
Call trace:
dump_backtrace+0xf8/0x148
show_stack+0x20/0x38
dump_stack_lvl+0xb4/0xf8
dump_stack+0x18/0x40
__might_resched+0x248/0x2a0
__might_sleep+0x50/0x88
down_write+0x30/0x150
start_creating+0x90/0x1a0
__debugfs_create_file+0x5c/0x1b0
debugfs_create_file+0x34/0x48
kvm_reset_sys_regs+0x120/0x1e8
kvm_reset_vcpu+0x148/0x270
kvm_arch_vcpu_ioctl+0xddc/0x1788
kvm_vcpu_ioctl+0xb6c/0x13f0
__arm64_sys_ioctl+0x98/0xd8
invoke_syscall+0x48/0x108
el0_svc_common+0xb4/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x54/0x128
el0t_64_sync_handler+0x68/0xc0
el0t_64_sync+0x1a8/0x1b0
kvm_reset_vcpu() disables preemption as it needs to unload vCPU state
from the CPU to twiddle with it, which subsequently explodes when
taking the parent inode's rwsem while creating the idreg debugfs file.
Fix it by moving the initialization to kvm_arch_create_vm_debugfs().
Fixes: 891766581d ("KVM: arm64: Add debugfs file for guest's ID registers")
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240227094115.1723330-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
We already trap a bunch of existing features for the purpose of
disabling them (MAIR2, POR, ACCDATA, SME...).
Let's move them over to our brand new FGU infrastructure.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-20-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
VNCR-backed "registers" are actually only memory. Which means that
there is zero control over what the guest can write, and that it
is the hypervisor's job to actually sanitise the content of the
backing store. Yeah, this is fun.
In order to preserve some form of sanity, add a repainting mechanism
that makes use of a per-VM set of RES0/RES1 masks, one pair per VNCR
register. These masks get applied on access to the backing store via
__vcpu_sys_reg(), ensuring that the state that is consumed by KVM is
correct.
So far, nothing populates these masks, but stay tuned.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20240214131827.2856277-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Print which of the hyp modes is being used (hVHE, nVHE).
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240209103719.3813599-1-joey.gouly@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
- Use memdup_array_user() to harden against overflow.
- Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
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Merge tag 'kvm-x86-generic-6.8' of https://github.com/kvm-x86/linux into HEAD
Common KVM changes for 6.8:
- Use memdup_array_user() to harden against overflow.
- Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
- LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
base granule sizes. Branch shared with the arm64 tree.
- Large Fine-Grained Trap rework, bringing some sanity to the
feature, although there is more to come. This comes with
a prefix branch shared with the arm64 tree.
- Some additional Nested Virtualization groundwork, mostly
introducing the NV2 VNCR support and retargetting the NV
support to that version of the architecture.
- A small set of vgic fixes and associated cleanups.
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Merge tag 'kvmarm-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for Linux 6.8
- LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
base granule sizes. Branch shared with the arm64 tree.
- Large Fine-Grained Trap rework, bringing some sanity to the
feature, although there is more to come. This comes with
a prefix branch shared with the arm64 tree.
- Some additional Nested Virtualization groundwork, mostly
introducing the NV2 VNCR support and retargetting the NV
support to that version of the architecture.
- A small set of vgic fixes and associated cleanups.
* kvm-arm64/nv-6.8-prefix:
: .
: Nested Virtualization support update, focussing on the
: NV2 support (VNCR mapping and such).
: .
KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg()
KVM: arm64: nv: Map VNCR-capable registers to a separate page
KVM: arm64: nv: Add EL2_REG_VNCR()/EL2_REG_REDIR() sysreg helpers
KVM: arm64: Introduce a bad_trap() primitive for unexpected trap handling
KVM: arm64: nv: Add include containing the VNCR_EL2 offsets
KVM: arm64: nv: Add non-VHE-EL2->EL1 translation helpers
KVM: arm64: nv: Drop EL12 register traps that are redirected to VNCR
KVM: arm64: nv: Compute NV view of idregs as a one-off
KVM: arm64: nv: Hoist vcpu_has_nv() into is_hyp_ctxt()
arm64: cpufeatures: Restrict NV support to FEAT_NV2
Signed-off-by: Marc Zyngier <maz@kernel.org>
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>
When failing to create a vcpu because (for example) it has a
duplicate vcpu_id, we destroy the vcpu. Amusingly, this leaves
the redistributor registered with the KVM_MMIO bus.
This is no good, and we should properly clean the mess. Force
a teardown of the vgic vcpu interface, including the RD device
before returning to the caller.
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231207151201.3028710-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
KVM_CAP_DEVICE_CTRL allows userspace to check if the kvm_device
framework (e.g. KVM_CREATE_DEVICE) is supported by KVM. Move
KVM_CAP_DEVICE_CTRL to the generic check for the two reasons:
1) it already supports arch agnostic usages (i.e. KVM_DEV_TYPE_VFIO).
For example, userspace VFIO implementation may needs to create
KVM_DEV_TYPE_VFIO on x86, riscv, or arm etc. It is simpler to have it
checked at the generic code than at each arch's code.
2) KVM_CREATE_DEVICE has been added to the generic code.
Link: https://lore.kernel.org/all/20221215115207.14784-1-wei.w.wang@intel.com
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Acked-by: Anup Patel <anup@brainfault.org> (riscv)
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20230315101606.10636-1-wei.w.wang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
