Previous commits have introduced infrastructure to enable the EL2 code
to manage its own stage 1 mappings. However, this was preliminary work,
and none of it is currently in use.
Put all of this together by elevating the mapping creation at EL2 when
memory protection is enabled. In this case, the host kernel running
at EL1 still creates _temporary_ EL2 mappings, only used while
initializing the hypervisor, but frees them right after.
As such, all calls to create_hyp_mappings() after kvm init has finished
turn into hypercalls, as the host now has no 'legal' way to modify the
hypevisor page tables directly.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-19-qperret@google.com
In order to re-map the guest vectors at EL2 when pKVM is enabled,
refactor __kvm_vector_slot2idx() and kvm_init_vector_slot() to move all
the address calculation logic in a static inline function.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-16-qperret@google.com
Currently, the hyp code cannot make full use of a bss, as the kernel
section is mapped read-only.
While this mapping could simply be changed to read-write, it would
intermingle even more the hyp and kernel state than they currently are.
Instead, introduce a __hyp_bss section, that uses reserved pages, and
create the appropriate RW hyp mappings during KVM init.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
Move the initialization of kvm_nvhe_init_params in a dedicated function
that is run early, and only once during KVM init, rather than every time
the KVM vectors are set and reset.
This also opens the opportunity for the hypervisor to change the init
structs during boot, hence simplifying the replacement of host-provided
page-table by the one the hypervisor will create for itself.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-5-qperret@google.com
Now that KVM is equipped to deal with SVE on nVHE, remove the code
preventing it from being used as well as the bits of documentation
that were mentioning the incompatibility.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Daniel Kiss <daniel.kiss@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"More fixes for ARM and x86"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: LAPIC: Advancing the timer expiration on guest initiated write
KVM: x86/mmu: Skip !MMU-present SPTEs when removing SP in exclusive mode
KVM: kvmclock: Fix vCPUs > 64 can't be online/hotpluged
kvm: x86: annotate RCU pointers
KVM: arm64: Fix exclusive limit for IPA size
KVM: arm64: Reject VM creation when the default IPA size is unsupported
KVM: arm64: Ensure I-cache isolation between vcpus of a same VM
KVM: arm64: Don't use cbz/adr with external symbols
KVM: arm64: Fix range alignment when walking page tables
KVM: arm64: Workaround firmware wrongly advertising GICv2-on-v3 compatibility
KVM: arm64: Rename __vgic_v3_get_ich_vtr_el2() to __vgic_v3_get_gic_config()
KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is available
KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key
KVM: arm64: Fix nVHE hyp panic host context restore
KVM: arm64: Avoid corrupting vCPU context register in guest exit
KVM: arm64: nvhe: Save the SPE context early
kvm: x86: use NULL instead of using plain integer as pointer
KVM: SVM: Connect 'npt' module param to KVM's internal 'npt_enabled'
KVM: x86: Ensure deadline timer has truly expired before posting its IRQ
It recently became apparent that the ARMv8 architecture has interesting
rules regarding attributes being used when fetching instructions
if the MMU is off at Stage-1.
In this situation, the CPU is allowed to fetch from the PoC and
allocate into the I-cache (unless the memory is mapped with
the XN attribute at Stage-2).
If we transpose this to vcpus sharing a single physical CPU,
it is possible for a vcpu running with its MMU off to influence
another vcpu running with its MMU on, as the latter is expected to
fetch from the PoU (and self-patching code doesn't flush below that
level).
In order to solve this, reuse the vcpu-private TLB invalidation
code to apply the same policy to the I-cache, nuking it every time
the vcpu runs on a physical CPU that ran another vcpu of the same
VM in the past.
This involve renaming __kvm_tlb_flush_local_vmid() to
__kvm_flush_cpu_context(), and inserting a local i-cache invalidation
there.
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210303164505.68492-1-maz@kernel.org
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU. Instead of the complex
"fast page fault" logic that is used in mmu.c, tdp_mmu.c uses an
rwlock so that page faults are concurrent, but the code that can run
against page faults is limited. Right now only page faults take the
lock for reading; in the future this will be extended to some
cases of page table destruction. I hope to switch the default MMU
around 5.12-rc3 (some testing was delayed due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"x86:
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU.
Instead of the complex "fast page fault" logic that is used in
mmu.c, tdp_mmu.c uses an rwlock so that page faults are concurrent,
but the code that can run against page faults is limited. Right now
only page faults take the lock for reading; in the future this will
be extended to some cases of page table destruction. I hope to
switch the default MMU around 5.12-rc3 (some testing was delayed
due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization
unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64:
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (192 commits)
KVM: x86/xen: Explicitly pad struct compat_vcpu_info to 64 bytes
KVM: selftests: Don't bother mapping GVA for Xen shinfo test
KVM: selftests: Fix hex vs. decimal snafu in Xen test
KVM: selftests: Fix size of memslots created by Xen tests
KVM: selftests: Ignore recently added Xen tests' build output
KVM: selftests: Add missing header file needed by xAPIC IPI tests
KVM: selftests: Add operand to vmsave/vmload/vmrun in svm.c
KVM: SVM: Make symbol 'svm_gp_erratum_intercept' static
locking/arch: Move qrwlock.h include after qspinlock.h
KVM: PPC: Book3S HV: Fix host radix SLB optimisation with hash guests
KVM: PPC: Book3S HV: Ensure radix guest has no SLB entries
KVM: PPC: Don't always report hash MMU capability for P9 < DD2.2
KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path
KVM: PPC: remove unneeded semicolon
KVM: PPC: Book3S HV: Use POWER9 SLBIA IH=6 variant to clear SLB
KVM: PPC: Book3S HV: No need to clear radix host SLB before loading HPT guest
KVM: PPC: Book3S HV: Fix radix guest SLB side channel
KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support
KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWR
KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWR
...
- vDSO build improvements including support for building with BSD.
- Cleanup to the AMU support code and initialisation rework to support
cpufreq drivers built as modules.
- Removal of synthetic frame record from exception stack when entering
the kernel from EL0.
- Add support for the TRNG firmware call introduced by Arm spec
DEN0098.
- Cleanup and refactoring across the board.
- Avoid calling arch_get_random_seed_long() from
add_interrupt_randomness()
- Perf and PMU updates including support for Cortex-A78 and the v8.3
SPE extensions.
- Significant steps along the road to leaving the MMU enabled during
kexec relocation.
- Faultaround changes to initialise prefaulted PTEs as 'old' when
hardware access-flag updates are supported, which drastically
improves vmscan performance.
- CPU errata updates for Cortex-A76 (#1463225) and Cortex-A55
(#1024718)
- Preparatory work for yielding the vector unit at a finer granularity
in the crypto code, which in turn will one day allow us to defer
softirq processing when it is in use.
- Support for overriding CPU ID register fields on the command-line.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
- vDSO build improvements including support for building with BSD.
- Cleanup to the AMU support code and initialisation rework to support
cpufreq drivers built as modules.
- Removal of synthetic frame record from exception stack when entering
the kernel from EL0.
- Add support for the TRNG firmware call introduced by Arm spec
DEN0098.
- Cleanup and refactoring across the board.
- Avoid calling arch_get_random_seed_long() from
add_interrupt_randomness()
- Perf and PMU updates including support for Cortex-A78 and the v8.3
SPE extensions.
- Significant steps along the road to leaving the MMU enabled during
kexec relocation.
- Faultaround changes to initialise prefaulted PTEs as 'old' when
hardware access-flag updates are supported, which drastically
improves vmscan performance.
- CPU errata updates for Cortex-A76 (#1463225) and Cortex-A55
(#1024718)
- Preparatory work for yielding the vector unit at a finer granularity
in the crypto code, which in turn will one day allow us to defer
softirq processing when it is in use.
- Support for overriding CPU ID register fields on the command-line.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (85 commits)
drivers/perf: Replace spin_lock_irqsave to spin_lock
mm: filemap: Fix microblaze build failure with 'mmu_defconfig'
arm64: Make CPU_BIG_ENDIAN depend on ld.bfd or ld.lld 13.0.0+
arm64: cpufeatures: Allow disabling of Pointer Auth from the command-line
arm64: Defer enabling pointer authentication on boot core
arm64: cpufeatures: Allow disabling of BTI from the command-line
arm64: Move "nokaslr" over to the early cpufeature infrastructure
KVM: arm64: Document HVC_VHE_RESTART stub hypercall
arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0
arm64: Add an aliasing facility for the idreg override
arm64: Honor VHE being disabled from the command-line
arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line
arm64: cpufeature: Add an early command-line cpufeature override facility
arm64: Extract early FDT mapping from kaslr_early_init()
arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding()
arm64: cpufeature: Add global feature override facility
arm64: Move SCTLR_EL1 initialisation to EL-agnostic code
arm64: Simplify init_el2_state to be non-VHE only
arm64: Move VHE-specific SPE setup to mutate_to_vhe()
arm64: Drop early setting of MDSCR_EL2.TPMS
...
Admitedly, passing id_aa64mmfr1.vh=0 on the command-line isn't
that easy to understand, and it is likely that users would much
prefer write "kvm-arm.mode=nvhe", or "...=protected".
So here you go. This has the added advantage that we can now
always honor the "kvm-arm.mode=protected" option, even when
booting on a VHE system.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-18-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
We will need to recognize pointers in .rodata specific to hyp, so
establish a .hyp.rodata ELF section. Merge it with the existing
.hyp.data..ro_after_init as they are treated the same at runtime.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-3-dbrazdil@google.com
KASAN in HW_TAGS mode will store MTE tags in the top byte of the
pointer. When computing the offset for TPIDR_EL2 we don't want anything
in the top byte, so remove the tag to ensure the computation is correct
no matter what the tag.
Fixes: 94ab5b61ee ("kasan, arm64: enable CONFIG_KASAN_HW_TAGS")
Signed-off-by: Steven Price <steven.price@arm.com>
[maz: added comment]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210108161254.53674-1-steven.price@arm.com
The __init annotations on hyp_cpu_pm_{init,exit} are obviously incorrect,
and the build system shouts at you if you enable DEBUG_SECTION_MISMATCH.
Nothing really bad happens as we never execute that code outside of the
init context, but we can't label the callers as __int either, as kvm_init
isn't __init itself. Oh well.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20201223120854.255347-1-maz@kernel.org
kvm_vgic_map_resources() is called when a VCPU if first run and it maps all
the VGIC MMIO regions. To prevent double-initialization, the VGIC uses the
ready variable to keep track of the state of resources and the global KVM
mutex to protect against concurrent accesses. After the lock is taken, the
variable is checked again in case another VCPU took the lock between the
current VCPU reading ready equals false and taking the lock.
The double-checked lock pattern is spread across four different functions:
in kvm_vcpu_first_run_init(), in kvm_vgic_map_resource() and in
vgic_{v2,v3}_map_resources(), which makes it hard to reason about and
introduces minor code duplication. Consolidate the checks in
kvm_vgic_map_resources(), where the lock is taken.
No functional change intended.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201201150157.223625-4-alexandru.elisei@arm.com
Although there is nothing wrong with the current host PSCI relay
implementation, we can clean it up and remove some of the helpers
that do not improve the overall readability of the legacy PSCI 0.1
handling.
Opportunity is taken to turn the bitmap into a set of booleans,
and creative use of preprocessor macros make init and check
more concise/readable.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Small cleanup moving declarations of hyp-exported variables to
kvm_host.h and using macros to avoid having to refer to them with
kvm_nvhe_sym() in host.
No functional change intended.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201208142452.87237-5-dbrazdil@google.com
PSCI driver exposes a struct containing the PSCI v0.1 function IDs
configured in the DT. However, the struct does not convey the
information whether these were set from DT or contain the default value
zero. This could be a problem for PSCI proxy in KVM protected mode.
Extend config passed to KVM with a bit mask with individual bits set
depending on whether the corresponding function pointer in psci_ops is
set, eg. set bit for PSCI_CPU_SUSPEND if psci_ops.cpu_suspend != NULL.
Previously config was split into multiple global variables. Put
everything into a single struct for convenience.
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201208142452.87237-2-dbrazdil@google.com
With protected nVHE hyp code interception host's PSCI SMCs, the host
starts seeing new CPUs boot in EL1 instead of EL2. The kernel logic
that keeps track of the boot mode needs to be adjusted.
Add a static key enabled if KVM protected mode initialization is
successful.
When the key is enabled, is_hyp_mode_available continues to report
`true` because its users either treat it as a check whether KVM will be
/ was initialized, or whether stub HVCs can be made (eg. hibernate).
is_hyp_mode_mismatched is changed to report `false` when the key is
enabled. That's because all cores' modes matched at the point of KVM
init and KVM will not allow cores not present at init to boot. That
said, the function is never used after KVM is initialized.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-27-dbrazdil@google.com
KVM by default keeps the stub vector installed and installs the nVHE
vector only briefly for init and later on demand. Change this policy
to install the vector at init and then never uninstall it if the kernel
was given the protected KVM command line parameter.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-25-dbrazdil@google.com
Add a handler of PSCI SMCs in nVHE hyp code. The handler is initialized
with the version used by the host's PSCI driver and the function IDs it
was configured with. If the SMC function ID matches one of the
configured PSCI calls (for v0.1) or falls into the PSCI function ID
range (for v0.2+), the SMC is handled by the PSCI handler. For now, all
SMCs return PSCI_RET_NOT_SUPPORTED.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-17-dbrazdil@google.com
When KVM starts validating host's PSCI requests, it will need to map
MPIDR back to the CPU ID. To this end, copy cpu_logical_map into nVHE
hyp memory when KVM is initialized.
Only copy the information for CPUs that are online at the point of KVM
initialization so that KVM rejects CPUs whose features were not checked
against the finalized capabilities.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-15-dbrazdil@google.com
Add rules for renaming the .data..ro_after_init ELF section in KVM nVHE
object files to .hyp.data..ro_after_init, linking it into the kernel
and mapping it in hyp at runtime.
The section is RW to the host, then mapped RO in hyp. The expectation is
that the host populates the variables in the section and they are never
changed by hyp afterwards.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-13-dbrazdil@google.com
MAIR_EL2 and TCR_EL2 are currently initialized from their _EL1 values.
This will not work once KVM starts intercepting PSCI ON/SUSPEND SMCs
and initializing EL2 state before EL1 state.
Obtain the EL1 values during KVM init and store them in the init params
struct. The struct will stay in memory and can be used when booting new
cores.
Take the opportunity to move copying the T0SZ value from idmap_t0sz in
KVM init rather than in .hyp.idmap.text. This avoids the need for the
idmap_t0sz symbol alias.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-12-dbrazdil@google.com
Once we start initializing KVM on newly booted cores before the rest of
the kernel, parameters to __do_hyp_init will need to be provided by EL2
rather than EL1. At that point it will not be possible to pass its three
arguments directly because PSCI_CPU_ON only supports one context
argument.
Refactor __do_hyp_init to accept its parameters in a struct. This
prepares the code for KVM booting cores as well as removes any limits on
the number of __do_hyp_init arguments.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-11-dbrazdil@google.com
KVM precomputes the hyp VA of __kvm_hyp_host_vector, essentially a
constant (minus ASLR), before passing it to __kvm_hyp_init.
Now that we have alternatives for converting kimg VA to hyp VA, replace
this with computing the constant inside __kvm_hyp_init, thus removing
the need for an argument.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-10-dbrazdil@google.com
Expose the boolean value whether the system is running with KVM in
protected mode (nVHE + kernel param). CPU capability was selected over
a global variable to allow use in alternatives.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-3-dbrazdil@google.com
Add an early parameter that allows users to select the mode of operation
for KVM/arm64.
For now, the only supported value is "protected". By passing this flag
users opt into the hypervisor placing additional restrictions on the
host kernel. These allow the hypervisor to spawn guests whose state is
kept private from the host. Restrictions will include stage-2 address
translation to prevent host from accessing guest memory, filtering its
SMC calls, etc.
Without this parameter, the default behaviour remains selecting VHE/nVHE
based on hardware support and CONFIG_ARM64_VHE.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-2-dbrazdil@google.com
Cores that predate the introduction of ID_AA64PFR0_EL1.CSV3 to
the ARMv8 architecture have this field set to 0, even of some of
them are not affected by the vulnerability.
The kernel maintains a list of unaffected cores (A53, A55 and a few
others) so that it doesn't impose an expensive mitigation uncessarily.
As we do for CSV2, let's expose the CSV3 property to guests that run
on HW that is effectively not vulnerable. This can be reset to zero
by writing to the ID register from userspace, ensuring that VMs can
be migrated despite the new property being set.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
kvm_arch_vm_ioctl_check_extension() is only called from
kvm_vm_ioctl_check_extension(), so we can inline it and remove the extra
function.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201118194402.2892-3-will@kernel.org
The hyp vectors entry corresponding to HYP_VECTOR_DIRECT (i.e. when
neither Spectre-v2 nor Spectre-v3a are present) is unused, as we can
simply dispatch straight to __kvm_hyp_vector in this case.
Remove the redundant vector, and massage the logic for resolving a slot
to a vectors entry.
Reported-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201113113847.21619-11-will@kernel.org
Since ARM64_HARDEN_EL2_VECTORS is really a mitigation for Spectre-v3a,
rename it accordingly for consistency with the v2 and v4 mitigation.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-9-will@kernel.org
The EL2 vectors installed when a guest is running point at one of the
following configurations for a given CPU:
- Straight at __kvm_hyp_vector
- A trampoline containing an SMC sequence to mitigate Spectre-v2 and
then a direct branch to __kvm_hyp_vector
- A dynamically-allocated trampoline which has an indirect branch to
__kvm_hyp_vector
- A dynamically-allocated trampoline containing an SMC sequence to
mitigate Spectre-v2 and then an indirect branch to __kvm_hyp_vector
The indirect branches mean that VA randomization at EL2 isn't trivially
bypassable using Spectre-v3a (where the vector base is readable by the
guest).
Rather than populate these vectors dynamically, configure everything
statically and use an enumerated type to identify the vector "slot"
corresponding to one of the configurations above. This both simplifies
the code, but also makes it much easier to implement at EL2 later on.
Signed-off-by: Will Deacon <will@kernel.org>
[maz: fixed double call to kvm_init_vector_slots() on nVHE]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-8-will@kernel.org
The BP hardening helpers are an integral part of the Spectre-v2
mitigation, so move them into asm/spectre.h and inline the
arm64_get_bp_hardening_data() function at the same time.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-6-will@kernel.org
Branch predictor hardening of the hyp vectors is partially driven by a
couple of global variables ('__kvm_bp_vect_base' and
'__kvm_harden_el2_vector_slot'). However, these are only used within a
single compilation unit, so internalise them there instead.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-5-will@kernel.org
kvm_get_hyp_vector() has only one caller, so move it out of kvm_mmu.h
and inline it into a new function, cpu_set_hyp_vector(), for setting
the vector.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-4-will@kernel.org
The bulk of the work in kvm_map_vector() is conditional on the
ARM64_HARDEN_EL2_VECTORS capability, so return early if that is not set
and make the code a bit easier to read.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-3-will@kernel.org
'__kvm_bp_vect_base' is only used when dealing with the hardened vectors
so remove the redundant assignments in kvm_map_vectors().
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20201113113847.21619-2-will@kernel.org
We now expose ID_AA64PFR0_EL1.CSV2=1 to guests running on hosts
that are immune to Spectre-v2, but that don't have this field set,
most likely because they predate the specification.
However, this prevents the migration of guests that have started on
a host the doesn't fake this CSV2 setting to one that does, as KVM
rejects the write to ID_AA64PFR0_EL2 on the grounds that it isn't
what is already there.
In order to fix this, allow userspace to set this field as long as
this doesn't result in a promising more than what is already there
(setting CSV2 to 0 is acceptable, but setting it to 1 when it is
already set to 0 isn't).
Fixes: e1026237f9 ("KVM: arm64: Set CSV2 for guests on hardware unaffected by Spectre-v2")
Reported-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201110141308.451654-2-maz@kernel.org
kvm_coproc.h used to serve as a compatibility layer for the files
shared between the 32 and 64 bit ports.
Another one bites the dust...
Signed-off-by: Marc Zyngier <maz@kernel.org>
* selftest fix
* Force PTE mapping on device pages provided via VFIO
* Fix detection of cacheable mapping at S2
* Fallback to PMD/PTE mappings for composite huge pages
* Fix accounting of Stage-2 PGD allocation
* Fix AArch32 handling of some of the debug registers
* Simplify host HYP entry
* Fix stray pointer conversion on nVHE TLB invalidation
* Fix initialization of the nVHE code
* Simplify handling of capabilities exposed to HYP
* Nuke VCPUs caught using a forbidden AArch32 EL0
x86:
* new nested virtualization selftest
* Miscellaneous fixes
* make W=1 fixes
* Reserve new CPUID bit in the KVM leaves
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"ARM:
- selftest fix
- force PTE mapping on device pages provided via VFIO
- fix detection of cacheable mapping at S2
- fallback to PMD/PTE mappings for composite huge pages
- fix accounting of Stage-2 PGD allocation
- fix AArch32 handling of some of the debug registers
- simplify host HYP entry
- fix stray pointer conversion on nVHE TLB invalidation
- fix initialization of the nVHE code
- simplify handling of capabilities exposed to HYP
- nuke VCPUs caught using a forbidden AArch32 EL0
x86:
- new nested virtualization selftest
- miscellaneous fixes
- make W=1 fixes
- reserve new CPUID bit in the KVM leaves"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: vmx: remove unused variable
KVM: selftests: Don't require THP to run tests
KVM: VMX: eVMCS: make evmcs_sanitize_exec_ctrls() work again
KVM: selftests: test behavior of unmapped L2 APIC-access address
KVM: x86: Fix NULL dereference at kvm_msr_ignored_check()
KVM: x86: replace static const variables with macros
KVM: arm64: Handle Asymmetric AArch32 systems
arm64: cpufeature: upgrade hyp caps to final
arm64: cpufeature: reorder cpus_have_{const, final}_cap()
KVM: arm64: Factor out is_{vhe,nvhe}_hyp_code()
KVM: arm64: Force PTE mapping on fault resulting in a device mapping
KVM: arm64: Use fallback mapping sizes for contiguous huge page sizes
KVM: arm64: Fix masks in stage2_pte_cacheable()
KVM: arm64: Fix AArch32 handling of DBGD{CCINT,SCRext} and DBGVCR
KVM: arm64: Allocate stage-2 pgd pages with GFP_KERNEL_ACCOUNT
KVM: arm64: Drop useless PAN setting on host EL1 to EL2 transition
KVM: arm64: Remove leftover kern_hyp_va() in nVHE TLB invalidation
KVM: arm64: Don't corrupt tpidr_el2 on failed HVC call
x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID
On a system without uniform support for AArch32 at EL0, it is possible
for the guest to force run AArch32 at EL0 and potentially cause an
illegal exception if running on a core without AArch32. Add an extra
check so that if we catch the guest doing that, then we prevent it from
running again by resetting vcpu->arch.target and return
ARM_EXCEPTION_IL.
We try to catch this misbehaviour as early as possible and not rely on
an illegal exception occuring to signal the problem. Attempting to run a
32bit app in the guest will produce an error from QEMU if the guest
exits while running in AArch32 EL0.
Tested on Juno by instrumenting the host to fake asym aarch32 and
instrumenting KVM to make the asymmetry visible to the guest.
[will: Incorporated feedback from Marc]
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201021104611.2744565-2-qais.yousef@arm.com
Link: https://lore.kernel.org/r/20201027215118.27003-2-will@kernel.org
On Cortex-A77 r0p0 and r1p0, a sequence of a non-cacheable or device load
and a store exclusive or PAR_EL1 read can cause a deadlock.
The workaround requires a DMB SY before and after a PAR_EL1 register
read. In addition, it's possible an interrupt (doing a device read) or
KVM guest exit could be taken between the DMB and PAR read, so we
also need a DMB before returning from interrupt and before returning to
a guest.
A deadlock is still possible with the workaround as KVM guests must also
have the workaround. IOW, a malicious guest can deadlock an affected
systems.
This workaround also depends on a firmware counterpart to enable the h/w
to insert DMB SY after load and store exclusive instructions. See the
errata document SDEN-1152370 v10 [1] for more information.
[1] https://static.docs.arm.com/101992/0010/Arm_Cortex_A77_MP074_Software_Developer_Errata_Notice_v10.pdf
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20201028182839.166037-2-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
