When introducing support for irqchip in userspace we needed a way to
mask the timer signal to prevent the guest continuously exiting due to a
screaming timer.
We did this by disabling the corresponding percpu interrupt on the
host interrupt controller, because we cannot rely on the host system
having a GIC, and therefore cannot make any assumptions about having an
active state to hide the timer signal.
Unfortunately, when introducing this feature, it became entirely
possible that a VCPU which belongs to a VM that has a userspace irqchip
can disable the vtimer irq on the host on some physical CPU, and then go
away without ever enabling the vtimer irq on that physical CPU again.
This means that using irqchips in userspace on a system that also
supports running VMs with an in-kernel GIC can prevent forward progress
from in-kernel GIC VMs.
Later on, when we started taking virtual timer interrupts in the arch
timer code, we would also leave this timer state active for userspace
irqchip VMs, because we leave it up to a VGIC-enabled guest to
deactivate the hardware IRQ using the HW bit in the LR.
Both issues are solved by only using the enable/disable trick on systems
that do not have a host GIC which supports the active state, because all
VMs on such systems must use irqchips in userspace. Systems that have a
working GIC with support for an active state use the active state to
mask the timer signal for both userspace and in-kernel irqchips.
Cc: Alexander Graf <agraf@suse.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: <stable@vger.kernel.org> # v4.12+
Fixes: d9e1397783 ("KVM: arm/arm64: Support arch timers with a userspace gic")
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
ARM:
- Include icache invalidation optimizations, improving VM startup time
- Support for forwarded level-triggered interrupts, improving
performance for timers and passthrough platform devices
- A small fix for power-management notifiers, and some cosmetic changes
PPC:
- Add MMIO emulation for vector loads and stores
- Allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
requiring the complex thread synchronization of older CPU versions
- Improve the handling of escalation interrupts with the XIVE interrupt
controller
- Support decrement register migration
- Various cleanups and bugfixes.
s390:
- Cornelia Huck passed maintainership to Janosch Frank
- Exitless interrupts for emulated devices
- Cleanup of cpuflag handling
- kvm_stat counter improvements
- VSIE improvements
- mm cleanup
x86:
- Hypervisor part of SEV
- UMIP, RDPID, and MSR_SMI_COUNT emulation
- Paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit
- Allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more AVX512
features
- Show vcpu id in its anonymous inode name
- Many fixes and cleanups
- Per-VCPU MSR bitmaps (already merged through x86/pti branch)
- Stable KVM clock when nesting on Hyper-V (merged through x86/hyperv)
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Merge tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Radim Krčmář:
"ARM:
- icache invalidation optimizations, improving VM startup time
- support for forwarded level-triggered interrupts, improving
performance for timers and passthrough platform devices
- a small fix for power-management notifiers, and some cosmetic
changes
PPC:
- add MMIO emulation for vector loads and stores
- allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
requiring the complex thread synchronization of older CPU versions
- improve the handling of escalation interrupts with the XIVE
interrupt controller
- support decrement register migration
- various cleanups and bugfixes.
s390:
- Cornelia Huck passed maintainership to Janosch Frank
- exitless interrupts for emulated devices
- cleanup of cpuflag handling
- kvm_stat counter improvements
- VSIE improvements
- mm cleanup
x86:
- hypervisor part of SEV
- UMIP, RDPID, and MSR_SMI_COUNT emulation
- paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit
- allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
AVX512 features
- show vcpu id in its anonymous inode name
- many fixes and cleanups
- per-VCPU MSR bitmaps (already merged through x86/pti branch)
- stable KVM clock when nesting on Hyper-V (merged through
x86/hyperv)"
* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
KVM: PPC: Book3S HV: Branch inside feature section
KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
KVM: PPC: Book3S PR: Fix broken select due to misspelling
KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
KVM: PPC: Book3S HV: Drop locks before reading guest memory
kvm: x86: remove efer_reload entry in kvm_vcpu_stat
KVM: x86: AMD Processor Topology Information
x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
kvm: embed vcpu id to dentry of vcpu anon inode
kvm: Map PFN-type memory regions as writable (if possible)
x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
KVM: arm/arm64: Fixup userspace irqchip static key optimization
KVM: arm/arm64: Fix userspace_irqchip_in_use counting
KVM: arm/arm64: Fix incorrect timer_is_pending logic
MAINTAINERS: update KVM/s390 maintainers
MAINTAINERS: add Halil as additional vfio-ccw maintainer
MAINTAINERS: add David as a reviewer for KVM/s390
...
Spectre v1 mitigation:
- back-end version of array_index_mask_nospec()
- masking of the syscall number to restrict speculation through the
syscall table
- masking of __user pointers prior to deference in uaccess routines
Spectre v2 mitigation update:
- using the new firmware SMC calling convention specification update
- removing the current PSCI GET_VERSION firmware call mitigation as
vendors are deploying new SMCCC-capable firmware
- additional branch predictor hardening for synchronous exceptions and
interrupts while in user mode
Meltdown v3 mitigation update for Cavium Thunder X: unaffected but
hardware erratum gets in the way. The kernel now starts with the page
tables mapped as global and switches to non-global if kpti needs to be
enabled.
Other:
- Theoretical trylock bug fixed
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull more arm64 updates from Catalin Marinas:
"As I mentioned in the last pull request, there's a second batch of
security updates for arm64 with mitigations for Spectre/v1 and an
improved one for Spectre/v2 (via a newly defined firmware interface
API).
Spectre v1 mitigation:
- back-end version of array_index_mask_nospec()
- masking of the syscall number to restrict speculation through the
syscall table
- masking of __user pointers prior to deference in uaccess routines
Spectre v2 mitigation update:
- using the new firmware SMC calling convention specification update
- removing the current PSCI GET_VERSION firmware call mitigation as
vendors are deploying new SMCCC-capable firmware
- additional branch predictor hardening for synchronous exceptions
and interrupts while in user mode
Meltdown v3 mitigation update:
- Cavium Thunder X is unaffected but a hardware erratum gets in the
way. The kernel now starts with the page tables mapped as global
and switches to non-global if kpti needs to be enabled.
Other:
- Theoretical trylock bug fixed"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (38 commits)
arm64: Kill PSCI_GET_VERSION as a variant-2 workaround
arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support
arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
arm/arm64: smccc: Make function identifiers an unsigned quantity
firmware/psci: Expose SMCCC version through psci_ops
firmware/psci: Expose PSCI conduit
arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
arm/arm64: KVM: Turn kvm_psci_version into a static inline
arm/arm64: KVM: Advertise SMCCC v1.1
arm/arm64: KVM: Implement PSCI 1.0 support
arm/arm64: KVM: Add smccc accessors to PSCI code
arm/arm64: KVM: Add PSCI_VERSION helper
arm/arm64: KVM: Consolidate the PSCI include files
arm64: KVM: Increment PC after handling an SMC trap
arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
arm64: entry: Apply BP hardening for suspicious interrupts from EL0
arm64: entry: Apply BP hardening for high-priority synchronous exceptions
arm64: futex: Mask __user pointers prior to dereference
...
A new feature of SMCCC 1.1 is that it offers firmware-based CPU
workarounds. In particular, SMCCC_ARCH_WORKAROUND_1 provides
BP hardening for CVE-2017-5715.
If the host has some mitigation for this issue, report that
we deal with it using SMCCC_ARCH_WORKAROUND_1, as we apply the
host workaround on every guest exit.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We're about to need kvm_psci_version in HYP too. So let's turn it
into a static inline, and pass the kvm structure as a second
parameter (so that HYP can do a kern_hyp_va on it).
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The new SMC Calling Convention (v1.1) allows for a reduced overhead
when calling into the firmware, and provides a new feature discovery
mechanism.
Make it visible to KVM guests.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
PSCI 1.0 can be trivially implemented by providing the FEATURES
call on top of PSCI 0.2 and returning 1.0 as the PSCI version.
We happily ignore everything else, as they are either optional or
are clarifications that do not require any additional change.
PSCI 1.0 is now the default until we decide to add a userspace
selection API.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Instead of open coding the accesses to the various registers,
let's add explicit SMCCC accessors.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As we're about to trigger a PSCI version explosion, it doesn't
hurt to introduce a PSCI_VERSION helper that is going to be
used everywhere.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As we're about to update the PSCI support, and because I'm lazy,
let's move the PSCI include file to include/kvm so that both
ARM architectures can find it.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The changes for this version include icache invalidation optimizations
(improving VM startup time), support for forwarded level-triggered
interrupts (improved performance for timers and passthrough platform
devices), a small fix for power-management notifiers, and some cosmetic
changes.
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Merge tag 'kvm-arm-for-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm
KVM/ARM Changes for v4.16
The changes for this version include icache invalidation optimizations
(improving VM startup time), support for forwarded level-triggered
interrupts (improved performance for timers and passthrough platform
devices), a small fix for power-management notifiers, and some cosmetic
changes.
When I introduced a static key to avoid work in the critical path for
userspace irqchips which is very rarely used, I accidentally messed up
my logic and used && where I should have used ||, because the point was
to short-circuit the evaluation in case userspace irqchips weren't even
in use.
This fixes an issue when running in-kernel irqchip VMs alongside
userspace irqchip VMs.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Fixes: c44c232ee2d3 ("KVM: arm/arm64: Avoid work when userspace iqchips are not used")
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
We were not decrementing the static key count in the right location.
kvm_arch_vcpu_destroy() is only called to clean up after a failed
VCPU create attempt, whereas kvm_arch_vcpu_free() is called on teardown
of the VM as well. Move the static key decrement call to
kvm_arch_vcpu_free().
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
After the recently introduced support for level-triggered mapped
interrupt, I accidentally left the VCPU thread busily going back and
forward between the guest and the hypervisor whenever the guest was
blocking, because I would always incorrectly report that a timer
interrupt was pending.
This is because the timer->irq.level field is not valid for mapped
interrupts, where we offload the level state to the hardware, and as a
result this field is always true.
Luckily the problem can be relatively easily solved by not checking the
cached signal state of either timer in kvm_timer_should_fire() but
instead compute the timer state on the fly, which we do already if the
cached signal state wasn't high. In fact, the only reason for checking
the cached signal state was a tiny optimization which would only be
potentially faster when the polling loop detects a pending timer
interrupt, which is quite unlikely.
Instead of duplicating the logic from kvm_arch_timer_handler(), we
enlighten kvm_timer_should_fire() to report something valid when the
timer state is loaded onto the hardware. We can then call this from
kvm_arch_timer_handler() as well and avoid the call to
__timer_snapshot_state() in kvm_arch_timer_get_input_level().
Reported-by: Tomasz Nowicki <tn@semihalf.com>
Tested-by: Tomasz Nowicki <tn@semihalf.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
- Security mitigations:
- variant 2: invalidating the branch predictor with a call to secure firmware
- variant 3: implementing KPTI for arm64
- 52-bit physical address support for arm64 (ARMv8.2)
- arm64 support for RAS (firmware first only) and SDEI (software
delegated exception interface; allows firmware to inject a RAS error
into the OS)
- Perf support for the ARM DynamIQ Shared Unit PMU
- CPUID and HWCAP bits updated for new floating point multiplication
instructions in ARMv8.4
- Removing some virtual memory layout printks during boot
- Fix initial page table creation to cope with larger than 32M kernel
images when 16K pages are enabled
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
"The main theme of this pull request is security covering variants 2
and 3 for arm64. I expect to send additional patches next week
covering an improved firmware interface (requires firmware changes)
for variant 2 and way for KPTI to be disabled on unaffected CPUs
(Cavium's ThunderX doesn't work properly with KPTI enabled because of
a hardware erratum).
Summary:
- Security mitigations:
- variant 2: invalidate the branch predictor with a call to
secure firmware
- variant 3: implement KPTI for arm64
- 52-bit physical address support for arm64 (ARMv8.2)
- arm64 support for RAS (firmware first only) and SDEI (software
delegated exception interface; allows firmware to inject a RAS
error into the OS)
- perf support for the ARM DynamIQ Shared Unit PMU
- CPUID and HWCAP bits updated for new floating point multiplication
instructions in ARMv8.4
- remove some virtual memory layout printks during boot
- fix initial page table creation to cope with larger than 32M kernel
images when 16K pages are enabled"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (104 commits)
arm64: Fix TTBR + PAN + 52-bit PA logic in cpu_do_switch_mm
arm64: Turn on KPTI only on CPUs that need it
arm64: Branch predictor hardening for Cavium ThunderX2
arm64: Run enable method for errata work arounds on late CPUs
arm64: Move BP hardening to check_and_switch_context
arm64: mm: ignore memory above supported physical address size
arm64: kpti: Fix the interaction between ASID switching and software PAN
KVM: arm64: Emulate RAS error registers and set HCR_EL2's TERR & TEA
KVM: arm64: Handle RAS SErrors from EL2 on guest exit
KVM: arm64: Handle RAS SErrors from EL1 on guest exit
KVM: arm64: Save ESR_EL2 on guest SError
KVM: arm64: Save/Restore guest DISR_EL1
KVM: arm64: Set an impdef ESR for Virtual-SError using VSESR_EL2.
KVM: arm/arm64: mask/unmask daif around VHE guests
arm64: kernel: Prepare for a DISR user
arm64: Unconditionally enable IESB on exception entry/return for firmware-first
arm64: kernel: Survive corrected RAS errors notified by SError
arm64: cpufeature: Detect CPU RAS Extentions
arm64: sysreg: Move to use definitions for all the SCTLR bits
arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early
...
cpu_pm_enter() calls the pm notifier chain with CPU_PM_ENTER, then if
there is a failure: CPU_PM_ENTER_FAILED.
When KVM receives CPU_PM_ENTER it calls cpu_hyp_reset() which will
return us to the hyp-stub. If we subsequently get a CPU_PM_ENTER_FAILED,
KVM does nothing, leaving the CPU running with the hyp-stub, at odds
with kvm_arm_hardware_enabled.
Add CPU_PM_ENTER_FAILED as a fallthrough for CPU_PM_EXIT, this reloads
KVM based on kvm_arm_hardware_enabled. This is safe even if CPU_PM_ENTER
never gets as far as KVM, as cpu_hyp_reinit() calls cpu_hyp_reset()
to make sure the hyp-stub is loaded before reloading KVM.
Fixes: 67f6919766 ("arm64: kvm: allows kvm cpu hotplug")
Cc: <stable@vger.kernel.org> # v4.7+
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Three more fixes for v4.15 fixing incorrect huge page mappings on systems using
the contigious hint for hugetlbfs; supporting an alternative GICv4 init
sequence; and correctly implementing the ARM SMCC for HVC and SMC handling.
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Merge tag 'kvm-arm-fixes-for-v4.15-3-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm
KVM/ARM Fixes for v4.15, Round 3 (v2)
Three more fixes for v4.15 fixing incorrect huge page mappings on systems using
the contigious hint for hugetlbfs; supporting an alternative GICv4 init
sequence; and correctly implementing the ARM SMCC for HVC and SMC handling.
We expect to have firmware-first handling of RAS SErrors, with errors
notified via an APEI method. For systems without firmware-first, add
some minimal handling to KVM.
There are two ways KVM can take an SError due to a guest, either may be a
RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO,
or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit.
For SError that interrupt a guest and are routed to EL2 the existing
behaviour is to inject an impdef SError into the guest.
Add code to handle RAS SError based on the ESR. For uncontained and
uncategorized errors arm64_is_fatal_ras_serror() will panic(), these
errors compromise the host too. All other error types are contained:
For the fatal errors the vCPU can't make progress, so we inject a virtual
SError. We ignore contained errors where we can make progress as if
we're lucky, we may not hit them again.
If only some of the CPUs support RAS the guest will see the cpufeature
sanitised version of the id registers, but we may still take RAS SError
on this CPU. Move the SError handling out of handle_exit() into a new
handler that runs before we can be preempted. This allows us to use
this_cpu_has_cap(), via arm64_is_ras_serror().
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Non-VHE systems take an exception to EL2 in order to world-switch into the
guest. When returning from the guest KVM implicitly restores the DAIF
flags when it returns to the kernel at EL1.
With VHE none of this exception-level jumping happens, so KVMs
world-switch code is exposed to the host kernel's DAIF values, and KVM
spills the guest-exit DAIF values back into the host kernel.
On entry to a guest we have Debug and SError exceptions unmasked, KVM
has switched VBAR but isn't prepared to handle these. On guest exit
Debug exceptions are left disabled once we return to the host and will
stay this way until we enter user space.
Add a helper to mask/unmask DAIF around VHE guests. The unmask can only
happen after the hosts VBAR value has been synchronised by the isb in
__vhe_hyp_call (via kvm_call_hyp()). Masking could be as late as
setting KVMs VBAR value, but is kept here for symmetry.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit fa2a8445b1 incorrectly masks the index of the HYP ID map pgd
entry, causing a non-VHE kernel to hang during boot. This happens when
VA_BITS=48 and the ID map text is in 52-bit physical memory. In this
case we don't need an extra table level but need more entries in the
top-level table, so we need to map into hyp_pgd and need to use
__kvm_idmap_ptrs_per_pgd to mask in the extra bits. However,
__create_hyp_mappings currently masks by PTRS_PER_PGD instead.
Fix it so that we always use __kvm_idmap_ptrs_per_pgd for the HYP ID
map. This ensures that we use the larger mask for the top-level ID map
table when it has more entries. In all other cases, PTRS_PER_PGD is used
as normal.
Fixes: fa2a8445b1 ("arm64: allow ID map to be extended to 52 bits")
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
kvm_host_cpu_state is a per-cpu allocation made from kvm_arch_init()
used to store the host EL1 registers when KVM switches to a guest.
Make it easier for ASM to generate pointers into this per-cpu memory
by making it a static allocation.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit 3d1ad640f8 ("KVM: arm/arm64: Fix GICv4 ITS initialization
issues") moved the vgic_supports_direct_msis() check in vgic_v4_init().
However when vgic_v4_init is called from vgic_its_create(), the has_its
field is not yet set. Hence vgic_supports_direct_msis returns false and
vgic_v4_init does nothing.
The gic/its init sequence is a bit messy, so let's be specific about the
prerequisite checks in the various call paths instead of relying on a
common wrapper.
Fixes: 3d1ad640f8 ("KVM: arm/arm64: Fix GICv4 ITS initialization issues")
Reported-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
KVM only supports PMD hugepages at stage 2 but doesn't actually check
that the provided hugepage memory pagesize is PMD_SIZE before populating
stage 2 entries.
In cases where the backing hugepage size is smaller than PMD_SIZE (such
as when using contiguous hugepages), KVM can end up creating stage 2
mappings that extend beyond the supplied memory.
Fix this by checking for the pagesize of userspace vma before creating
PMD hugepage at stage 2.
Fixes: 66b3923a1a ("arm64: hugetlb: add support for PTE contiguous bit")
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: <stable@vger.kernel.org> # v4.5+
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Now that we have per-CPU vectors, let's plug then in the KVM/arm64 code.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The vcpu parameter isn't used for anything, and gets in the way of
further cleanups. Let's get rid of it.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
So far, we loose the Exec property whenever we take permission
faults, as we always reconstruct the PTE/PMD from scratch. This
can be counter productive as we can end-up with the following
fault sequence:
X -> RO -> ROX -> RW -> RWX
Instead, we can lookup the existing PTE/PMD and clear the XN bit in the
new entry if it was already cleared in the old one, leadig to a much
nicer fault sequence:
X -> ROX -> RWX
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The only case where we actually need to perform a dcache maintenance
is when we map the page for the first time, and subsequent permission
faults do not require cache maintenance. Let's make it conditional
on not being a permission fault (and thus a translation fault).
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
We've so far eagerly invalidated the icache, no matter how
the page was faulted in (data or prefetch abort).
But we can easily track execution by setting the XN bits
in the S2 page tables, get the prefetch abort at HYP and
perform the icache invalidation at that time only.
As for most VMs, the instruction working set is pretty
small compared to the data set, this is likely to save
some traffic (specially as the invalidation is broadcast).
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
As we're about to introduce opportunistic invalidation of the icache,
let's split dcache and icache flushing.
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
kvm_hyp.h has an odd dependency on kvm_mmu.h, which makes the
opposite inclusion impossible. Let's start with breaking that
useless dependency.
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
We currently check if the VM has a userspace irqchip in several places
along the critical path, and if so, we do some work which is only
required for having an irqchip in userspace. This is unfortunate, as we
could avoid doing any work entirely, if we didn't have to support
irqchip in userspace.
Realizing the userspace irqchip on ARM is mostly a developer or hobby
feature, and is unlikely to be used in servers or other scenarios where
performance is a priority, we can use a refcounted static key to only
check the irqchip configuration when we have at least one VM that uses
an irqchip in userspace.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The VGIC can now support the life-cycle of mapped level-triggered
interrupts, and we no longer have to read back the timer state on every
exit from the VM if we had an asserted timer interrupt signal, because
the VGIC already knows if we hit the unlikely case where the guest
disables the timer without ACKing the virtual timer interrupt.
This means we rework a bit of the code to factor out the functionality
to snapshot the timer state from vtimer_save_state(), and we can reuse
this functionality in the sync path when we have an irqchip in
userspace, and also to support our implementation of the
get_input_level() function for the timer.
This change also means that we can no longer rely on the timer's view of
the interrupt line to set the active state, because we no longer
maintain this state for mapped interrupts when exiting from the guest.
Instead, we only set the active state if the virtual interrupt is
active, and otherwise we simply let the timer fire again and raise the
virtual interrupt from the ISR.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
For mapped IRQs (with the HW bit set in the LR) we have to follow some
rules of the architecture. One of these rules is that VM must not be
allowed to deactivate a virtual interrupt with the HW bit set unless the
physical interrupt is also active.
This works fine when injecting mapped interrupts, because we leave it up
to the injector to either set EOImode==1 or manually set the active
state of the physical interrupt.
However, the guest can set virtual interrupt to be pending or active by
writing to the virtual distributor, which could lead to deactivating a
virtual interrupt with the HW bit set without the physical interrupt
being active.
We could set the physical interrupt to active whenever we are about to
enter the VM with a HW interrupt either pending or active, but that
would be really slow, especially on GICv2. So we take the long way
around and do the hard work when needed, which is expected to be
extremely rare.
When the VM sets the pending state for a HW interrupt on the virtual
distributor we set the active state on the physical distributor, because
the virtual interrupt can become active and then the guest can
deactivate it.
When the VM clears the pending state we also clear it on the physical
side, because the injector might otherwise raise the interrupt. We also
clear the physical active state when the virtual interrupt is not
active, since otherwise a SPEND/CPEND sequence from the guest would
prevent signaling of future interrupts.
Changing the state of mapped interrupts from userspace is not supported,
and it's expected that userspace unmaps devices from VFIO before
attempting to set the interrupt state, because the interrupt state is
driven by hardware.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The GIC sometimes need to sample the physical line of a mapped
interrupt. As we know this to be notoriously slow, provide a callback
function for devices (such as the timer) which can do this much faster
than talking to the distributor, for example by comparing a few
in-memory values. Fall back to the good old method of poking the
physical GIC if no callback is provided.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Level-triggered mapped IRQs are special because we only observe rising
edges as input to the VGIC, and we don't set the EOI flag and therefore
are not told when the level goes down, so that we can re-queue a new
interrupt when the level goes up.
One way to solve this problem is to side-step the logic of the VGIC and
special case the validation in the injection path, but it has the
unfortunate drawback of having to peak into the physical GIC state
whenever we want to know if the interrupt is pending on the virtual
distributor.
Instead, we can maintain the current semantics of a level triggered
interrupt by sort of treating it as an edge-triggered interrupt,
following from the fact that we only observe an asserting edge. This
requires us to be a bit careful when populating the LRs and when folding
the state back in though:
* We lower the line level when populating the LR, so that when
subsequently observing an asserting edge, the VGIC will do the right
thing.
* If the guest never acked the interrupt while running (for example if
it had masked interrupts at the CPU level while running), we have
to preserve the pending state of the LR and move it back to the
line_level field of the struct irq when folding LR state.
If the guest never acked the interrupt while running, but changed the
device state and lowered the line (again with interrupts masked) then
we need to observe this change in the line_level.
Both of the above situations are solved by sampling the physical line
and set the line level when folding the LR back.
* Finally, if the guest never acked the interrupt while running and
sampling the line reveals that the device state has changed and the
line has been lowered, we must clear the physical active state, since
we will otherwise never be told when the interrupt becomes asserted
again.
This has the added benefit of making the timer optimization patches
(https://lists.cs.columbia.edu/pipermail/kvmarm/2017-July/026343.html) a
bit simpler, because the timer code doesn't have to clear the active
state on the sync anymore. It also potentially improves the performance
of the timer implementation because the GIC knows the state or the LR
and only needs to clear the
active state when the pending bit in the LR is still set, where the
timer has to always clear it when returning from running the guest with
an injected timer interrupt.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The timer logic was designed after a strict idea of modeling an
interrupt line level in software, meaning that only transitions in the
level need to be reported to the VGIC. This works well for the timer,
because the arch timer code is in complete control of the device and can
track the transitions of the line.
However, as we are about to support using the HW bit in the VGIC not
just for the timer, but also for VFIO which cannot track transitions of
the interrupt line, we have to decide on an interface between the GIC
and other subsystems for level triggered mapped interrupts, which both
the timer and VFIO can use.
VFIO only sees an asserting transition of the physical interrupt line,
and tells the VGIC when that happens. That means that part of the
interrupt flow is offloaded to the hardware.
To use the same interface for VFIO devices and the timer, we therefore
have to change the timer (we cannot change VFIO because it doesn't know
the details of the device it is assigning to a VM).
Luckily, changing the timer is simple, we just need to stop 'caching'
the line level, but instead let the VGIC know the state of the timer
every time there is a potential change in the line level, and when the
line level should be asserted from the timer ISR. The VGIC can ignore
extra notifications using its validate mechanism.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
We are about to distinguish between userspace accesses and mmio traps
for a number of the mmio handlers. When the requester vcpu is NULL, it
means we are handling a userspace access.
Factor out the functionality to get the request vcpu into its own
function, mostly so we have a common place to document the semantics of
the return value.
Also take the chance to move the functionality outside of holding a
spinlock and instead explicitly disable and enable preemption. This
supports PREEMPT_RT kernels as well.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The __this_cpu_read() and __this_cpu_write() functions already implement
checks for the required preemption levels when using
CONFIG_DEBUG_PREEMPT which gives you nice error messages and such.
Therefore there is no need to explicitly check this using a BUG_ON() in
the code (which we don't do for other uses of per cpu variables either).
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Fix ptr_ret.cocci warnings:
virt/kvm/arm/vgic/vgic-its.c:971:1-3: WARNING: PTR_ERR_OR_ZERO can be used
Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
Generated by: scripts/coccinelle/api/ptr_ret.cocci
Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Currently, when using VA_BITS < 48, if the ID map text happens to be
placed in physical memory above VA_BITS, we increase the VA size (up to
48) and create a new table level, in order to map in the ID map text.
This is okay because the system always supports 48 bits of VA.
This patch extends the code such that if the system supports 52 bits of
VA, and the ID map text is placed that high up, then we increase the VA
size accordingly, up to 52.
One difference from the current implementation is that so far the
condition of VA_BITS < 48 has meant that the top level table is always
"full", with the maximum number of entries, and an extra table level is
always needed. Now, when VA_BITS = 48 (and using 64k pages), the top
level table is not full, and we simply need to increase the number of
entries in it, instead of creating a new table level.
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[catalin.marinas@arm.com: reduce arguments to __create_hyp_mappings()]
[catalin.marinas@arm.com: reworked/renamed __cpu_uses_extended_idmap_level()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The top 4 bits of a 52-bit physical address are positioned at bits 2..5
in the TTBR registers. Introduce a couple of macros to move the bits
there, and change all TTBR writers to use them.
Leave TTBR0 PAN code unchanged, to avoid complicating it. A system with
52-bit PA will have PAN anyway (because it's ARMv8.1 or later), and a
system without 52-bit PA can only use up to 48-bit PAs. A later patch in
this series will add a kconfig dependency to ensure PAN is configured.
In addition, when using 52-bit PA there is a special alignment
requirement on the top-level table. We don't currently have any VA_BITS
configuration that would violate the requirement, but one could be added
in the future, so add a compile-time BUG_ON to check for it.
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[catalin.marinas@arm.com: added TTBR_BADD_MASK_52 comment]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes:
- A bug in our handling of SPE state for non-vhe systems
- A bug that causes hyp unmapping to go off limits and crash the system on
shutdown
- Three timer fixes that were introduced as part of the timer optimizations
for v4.15
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Merge tag 'kvm-arm-fixes-for-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/ARM Fixes for v4.15, Round 2
Fixes:
- A bug in our handling of SPE state for non-vhe systems
- A bug that causes hyp unmapping to go off limits and crash the system on
shutdown
- Three timer fixes that were introduced as part of the timer optimizations
for v4.15
Reported by syzkaller:
BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm]
Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298
CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18
Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
Call Trace:
dump_stack+0xab/0xe1
print_address_description+0x6b/0x290
kasan_report+0x28a/0x370
write_mmio+0x11e/0x270 [kvm]
emulator_read_write_onepage+0x311/0x600 [kvm]
emulator_read_write+0xef/0x240 [kvm]
emulator_fix_hypercall+0x105/0x150 [kvm]
em_hypercall+0x2b/0x80 [kvm]
x86_emulate_insn+0x2b1/0x1640 [kvm]
x86_emulate_instruction+0x39a/0xb90 [kvm]
handle_exception+0x1b4/0x4d0 [kvm_intel]
vcpu_enter_guest+0x15a0/0x2640 [kvm]
kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm]
kvm_vcpu_ioctl+0x479/0x880 [kvm]
do_vfs_ioctl+0x142/0x9a0
SyS_ioctl+0x74/0x80
entry_SYSCALL_64_fastpath+0x23/0x9a
The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall)
to the guest memory, however, write_mmio tracepoint always prints 8 bytes
through *(u64 *)val since kvm splits the mmio access into 8 bytes. This
leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes
it by just accessing the bytes which we operate on.
Before patch:
syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f
After patch:
syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When enabling the timer on the first run, we fail to ever restore the
state and mark it as loaded. That means, that in the initial entry to
the VCPU ioctl, unless we exit to userspace for some reason such as a
pending signal, if the guest programs a timer and blocks, we will wait
forever, because we never read back the hardware state (the loaded flag
is not set), and so we think the timer is disabled, and we never
schedule a background soft timer.
The end result? The VCPU blocks forever, and the only solution is to
kill the thread.
Fixes: 4a2c4da125 ("arm/arm64: KVM: Load the timer state when enabling the timer")
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
The recent timer rework was assuming that once the timer was disabled,
we should no longer see any interrupts from the timer. This assumption
turns out to not be true, and instead we have to handle the case when
the timer ISR runs even after the timer has been disabled.
This requires a couple of changes:
First, we should never overwrite the cached guest state of the timer
control register when the ISR runs, because KVM may have disabled its
timers when doing vcpu_put(), even though the guest still had the timer
enabled.
Second, we shouldn't assume that the timer is actually firing just
because we see an interrupt, but we should check the actual state of the
timer in the timer control register to understand if the hardware timer
is really firing or not.
We also add an ISB to vtimer_save_state() to ensure the timer is
actually disabled once we enable interrupts, which should clarify the
intention of the implementation, and reduce the risk of unwanted
interrupts.
Fixes: b103cc3f10 ("KVM: arm/arm64: Avoid timer save/restore in vcpu entry/exit")
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Reported-by: Jia He <hejianet@gmail.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
If we don't have a usable GIC, do not try to set the vcpu affinity
as this is guaranteed to fail.
Reported-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
When we unmap the HYP memory, we try to be clever and unmap one
PGD at a time. If we start with a non-PGD aligned address and try
to unmap a whole PGD, things go horribly wrong in unmap_hyp_range
(addr and end can never match, and it all goes really badly as we
keep incrementing pgd and parse random memory as page tables...).
The obvious fix is to let unmap_hyp_range do what it does best,
which is to iterate over a range.
The size of the linear mapping, which begins at PAGE_OFFSET, can be
easily calculated by subtracting PAGE_OFFSET form high_memory, because
high_memory is defined as the linear map address of the last byte of
DRAM, plus one.
The size of the vmalloc region is given trivially by VMALLOC_END -
VMALLOC_START.
Cc: stable@vger.kernel.org
Reported-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Move the calls to vcpu_load() and vcpu_put() in to the architecture
specific implementations of kvm_arch_vcpu_ioctl() which dispatches
further architecture-specific ioctls on to other functions.
Some architectures support asynchronous vcpu ioctls which cannot call
vcpu_load() or take the vcpu->mutex, because that would prevent
concurrent execution with a running VCPU, which is the intended purpose
of these ioctls, for example because they inject interrupts.
We repeat the separate checks for these specifics in the architecture
code for MIPS, S390 and PPC, and avoid taking the vcpu->mutex and
calling vcpu_load for these ioctls.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move vcpu_load() and vcpu_put() into the architecture specific
implementations of kvm_arch_vcpu_ioctl_set_mpstate().
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Christoffer Dall