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Use the non-raw smp_processor_id() in the low hardware enable/disable
helpers as KVM absolutely relies on the CPU being stable, e.g. KVM would
end up with incorrect state if the task were migrated between accessing
cpus_hardware_enabled and actually enabling/disabling hardware.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-44-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Disable CPU hotplug when enabling/disabling hardware to prevent the
corner case where if the following sequence occurs:
1. A hotplugged CPU marks itself online in cpu_online_mask
2. The hotplugged CPU enables interrupt before invoking KVM's ONLINE
callback
3 hardware_{en,dis}able_all() is invoked on another CPU
the hotplugged CPU will be included in on_each_cpu() and thus get sent
through hardware_{en,dis}able_nolock() before kvm_online_cpu() is called.
start_secondary { ...
set_cpu_online(smp_processor_id(), true); <- 1
...
local_irq_enable(); <- 2
...
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); <- 3
}
KVM currently fudges around this race by keeping track of which CPUs have
done hardware enabling (see commit 1b6c016818a5 "KVM: Keep track of which
cpus have virtualization enabled"), but that's an inefficient, convoluted,
and hacky solution.
Signed-off-by: Chao Gao <chao.gao@intel.com>
[sean: split to separate patch, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-43-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The CPU STARTING section doesn't allow callbacks to fail. Move KVM's
hotplug callback to ONLINE section so that it can abort onlining a CPU in
certain cases to avoid potentially breaking VMs running on existing CPUs.
For example, when KVM fails to enable hardware virtualization on the
hotplugged CPU.
Place KVM's hotplug state before CPUHP_AP_SCHED_WAIT_EMPTY as it ensures
when offlining a CPU, all user tasks and non-pinned kernel tasks have left
the CPU, i.e. there cannot be a vCPU task around. So, it is safe for KVM's
CPU offline callback to disable hardware virtualization at that point.
Likewise, KVM's online callback can enable hardware virtualization before
any vCPU task gets a chance to run on hotplugged CPUs.
Drop kvm_x86_check_processor_compatibility()'s WARN that IRQs are
disabled, as the ONLINE section runs with IRQs disabled. The WARN wasn't
intended to be a requirement, e.g. disabling preemption is sufficient,
the IRQ thing was purely an aggressive sanity check since the helper was
only ever invoked via SMP function call.
Rename KVM's CPU hotplug callbacks accordingly.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
[sean: drop WARN that IRQs are disabled]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-42-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Drop kvm_arch_check_processor_compat() and its support code now that all
architecture implementations are nops.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390
Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-Id: <20221130230934.1014142-33-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Drop kvm_arch_init() and kvm_arch_exit() now that all implementations
are nops.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Anup Patel <anup@brainfault.org>
Message-Id: <20221130230934.1014142-30-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Drop kvm_arch_hardware_setup() and kvm_arch_hardware_unsetup() now that
all implementations are nops.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390
Acked-by: Anup Patel <anup@brainfault.org>
Message-Id: <20221130230934.1014142-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the call to kvm_vfio_ops_exit() further up kvm_exit() to try and
bring some amount of symmetry to the setup order in kvm_init(), and more
importantly so that the arch hooks are invoked dead last by kvm_exit().
This will allow arch code to move away from the arch hooks without any
change in ordering between arch code and common code in kvm_exit().
That kvm_vfio_ops_exit() is called last appears to be 100% arbitrary. It
was bolted on after the fact by commit 571ee1b68598 ("kvm: vfio: fix
unregister kvm_device_ops of vfio"). The nullified kvm_device_ops_table
is also local to kvm_main.c and is used only when there are active VMs,
so unless arch code is doing something truly bizarre, nullifying the
table earlier in kvm_exit() is little more than a nop.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20221130230934.1014142-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Allocate cpus_hardware_enabled after arch hardware setup so that arch
"init" and "hardware setup" are called back-to-back and thus can be
combined in a future patch. cpus_hardware_enabled is never used before
kvm_create_vm(), i.e. doesn't have a dependency with hardware setup and
only needs to be allocated before /dev/kvm is exposed to userspace.
Free the object before the arch hooks are invoked to maintain symmetry,
and so that arch code can move away from the hooks without having to
worry about ordering changes.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Message-Id: <20221130230934.1014142-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move initialization of KVM's IRQ FD workqueue below arch hardware setup
as a step towards consolidating arch "init" and "hardware setup", and
eventually towards dropping the hooks entirely. There is no dependency
on the workqueue being created before hardware setup, the workqueue is
used only when destroying VMs, i.e. only needs to be created before
/dev/kvm is exposed to userspace.
Move the destruction of the workqueue before the arch hooks to maintain
symmetry, and so that arch code can move away from the hooks without
having to worry about ordering changes.
Reword the comment about kvm_irqfd_init() needing to come after
kvm_arch_init() to call out that kvm_arch_init() must come before common
KVM does _anything_, as x86 very subtly relies on that behavior to deal
with multiple calls to kvm_init(), e.g. if userspace attempts to load
kvm_amd.ko and kvm_intel.ko. Tag the code with a FIXME, as x86's subtle
requirement is gross, and invoking an arch callback as the very first
action in a helper that is called only from arch code is silly.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Register /dev/kvm, i.e. expose KVM to userspace, only after all other
setup has completed. Once /dev/kvm is exposed, userspace can start
invoking KVM ioctls, creating VMs, etc... If userspace creates a VM
before KVM is done with its configuration, bad things may happen, e.g.
KVM will fail to properly migrate vCPU state if a VM is created before
KVM has registered preemption notifiers.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86:
* Change tdp_mmu to a read-only parameter
* Separate TDP and shadow MMU page fault paths
* Enable Hyper-V invariant TSC control
selftests:
* Use TAP interface for kvm_binary_stats_test and tsc_msrs_test
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86:
* several fixes to nested VMX execution controls
* fixes and clarification to the documentation for Xen emulation
* do not unnecessarily release a pmu event with zero period
* MMU fixes
* fix Coverity warning in kvm_hv_flush_tlb()
selftests:
* fixes for the ucall mechanism in selftests
* other fixes mostly related to compilation with clang
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No code is using KVM_MMU_READ_LOCK() or KVM_MMU_READ_UNLOCK(). They
used to be in virt/kvm/pfncache.c:
KVM_MMU_READ_LOCK(kvm);
retry = mmu_notifier_retry_hva(kvm, mmu_seq, uhva);
KVM_MMU_READ_UNLOCK(kvm);
However, since 58cd407ca4c6 ("KVM: Fix multiple races in gfn=>pfn cache
refresh", 2022-05-25) the code is only relying on the MMU notifier's
invalidation count and sequence number.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221207120617.9409-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Pull kvm updates from Paolo Bonzini:
"ARM64:
- Enable the per-vcpu dirty-ring tracking mechanism, together with an
option to keep the good old dirty log around for pages that are
dirtied by something other than a vcpu.
- Switch to the relaxed parallel fault handling, using RCU to delay
page table reclaim and giving better performance under load.
- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
option, which multi-process VMMs such as crosvm rely on (see merge
commit 382b5b87a97d: "Fix a number of issues with MTE, such as
races on the tags being initialised vs the PG_mte_tagged flag as
well as the lack of support for VM_SHARED when KVM is involved.
Patches from Catalin Marinas and Peter Collingbourne").
- Merge the pKVM shadow vcpu state tracking that allows the
hypervisor to have its own view of a vcpu, keeping that state
private.
- Add support for the PMUv3p5 architecture revision, bringing support
for 64bit counters on systems that support it, and fix the
no-quite-compliant CHAIN-ed counter support for the machines that
actually exist out there.
- Fix a handful of minor issues around 52bit VA/PA support (64kB
pages only) as a prefix of the oncoming support for 4kB and 16kB
pages.
- Pick a small set of documentation and spelling fixes, because no
good merge window would be complete without those.
s390:
- Second batch of the lazy destroy patches
- First batch of KVM changes for kernel virtual != physical address
support
- Removal of a unused function
x86:
- Allow compiling out SMM support
- Cleanup and documentation of SMM state save area format
- Preserve interrupt shadow in SMM state save area
- Respond to generic signals during slow page faults
- Fixes and optimizations for the non-executable huge page errata
fix.
- Reprogram all performance counters on PMU filter change
- Cleanups to Hyper-V emulation and tests
- Process Hyper-V TLB flushes from a nested guest (i.e. from a L2
guest running on top of a L1 Hyper-V hypervisor)
- Advertise several new Intel features
- x86 Xen-for-KVM:
- Allow the Xen runstate information to cross a page boundary
- Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured
- Add support for 32-bit guests in SCHEDOP_poll
- Notable x86 fixes and cleanups:
- One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).
- Reinstate IBPB on emulated VM-Exit that was incorrectly dropped
a few years back when eliminating unnecessary barriers when
switching between vmcs01 and vmcs02.
- Clean up vmread_error_trampoline() to make it more obvious that
params must be passed on the stack, even for x86-64.
- Let userspace set all supported bits in MSR_IA32_FEAT_CTL
irrespective of the current guest CPUID.
- Fudge around a race with TSC refinement that results in KVM
incorrectly thinking a guest needs TSC scaling when running on a
CPU with a constant TSC, but no hardware-enumerated TSC
frequency.
- Advertise (on AMD) that the SMM_CTL MSR is not supported
- Remove unnecessary exports
Generic:
- Support for responding to signals during page faults; introduces
new FOLL_INTERRUPTIBLE flag that was reviewed by mm folks
Selftests:
- Fix an inverted check in the access tracking perf test, and restore
support for asserting that there aren't too many idle pages when
running on bare metal.
- Fix build errors that occur in certain setups (unsure exactly what
is unique about the problematic setup) due to glibc overriding
static_assert() to a variant that requires a custom message.
- Introduce actual atomics for clear/set_bit() in selftests
- Add support for pinning vCPUs in dirty_log_perf_test.
- Rename the so called "perf_util" framework to "memstress".
- Add a lightweight psuedo RNG for guest use, and use it to randomize
the access pattern and write vs. read percentage in the memstress
tests.
- Add a common ucall implementation; code dedup and pre-work for
running SEV (and beyond) guests in selftests.
- Provide a common constructor and arch hook, which will eventually
be used by x86 to automatically select the right hypercall (AMD vs.
Intel).
- A bunch of added/enabled/fixed selftests for ARM64, covering
memslots, breakpoints, stage-2 faults and access tracking.
- x86-specific selftest changes:
- Clean up x86's page table management.
- Clean up and enhance the "smaller maxphyaddr" test, and add a
related test to cover generic emulation failure.
- Clean up the nEPT support checks.
- Add X86_PROPERTY_* framework to retrieve multi-bit CPUID values.
- Fix an ordering issue in the AMX test introduced by recent
conversions to use kvm_cpu_has(), and harden the code to guard
against similar bugs in the future. Anything that tiggers
caching of KVM's supported CPUID, kvm_cpu_has() in this case,
effectively hides opt-in XSAVE features if the caching occurs
before the test opts in via prctl().
Documentation:
- Remove deleted ioctls from documentation
- Clean up the docs for the x86 MSR filter.
- Various fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (361 commits)
KVM: x86: Add proper ReST tables for userspace MSR exits/flags
KVM: selftests: Allocate ucall pool from MEM_REGION_DATA
KVM: arm64: selftests: Align VA space allocator with TTBR0
KVM: arm64: Fix benign bug with incorrect use of VA_BITS
KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow
KVM: x86: Advertise that the SMM_CTL MSR is not supported
KVM: x86: remove unnecessary exports
KVM: selftests: Fix spelling mistake "probabalistic" -> "probabilistic"
tools: KVM: selftests: Convert clear/set_bit() to actual atomics
tools: Drop "atomic_" prefix from atomic test_and_set_bit()
tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers
KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests
perf tools: Use dedicated non-atomic clear/set bit helpers
tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers
KVM: arm64: selftests: Enable single-step without a "full" ucall()
KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself
KVM: Remove stale comment about KVM_REQ_UNHALT
KVM: Add missing arch for KVM_CREATE_DEVICE and KVM_{SET,GET}_DEVICE_ATTR
KVM: Reference to kvm_userspace_memory_region in doc and comments
KVM: Delete all references to removed KVM_SET_MEMORY_ALIAS ioctl
...
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x86 Xen-for-KVM:
* Allow the Xen runstate information to cross a page boundary
* Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured
* add support for 32-bit guests in SCHEDOP_poll
x86 fixes:
* One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).
* Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few
years back when eliminating unnecessary barriers when switching between
vmcs01 and vmcs02.
* Clean up the MSR filter docs.
* Clean up vmread_error_trampoline() to make it more obvious that params
must be passed on the stack, even for x86-64.
* Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective
of the current guest CPUID.
* Fudge around a race with TSC refinement that results in KVM incorrectly
thinking a guest needs TSC scaling when running on a CPU with a
constant TSC, but no hardware-enumerated TSC frequency.
* Advertise (on AMD) that the SMM_CTL MSR is not supported
* Remove unnecessary exports
Selftests:
* Fix an inverted check in the access tracking perf test, and restore
support for asserting that there aren't too many idle pages when
running on bare metal.
* Fix an ordering issue in the AMX test introduced by recent conversions
to use kvm_cpu_has(), and harden the code to guard against similar bugs
in the future. Anything that tiggers caching of KVM's supported CPUID,
kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if
the caching occurs before the test opts in via prctl().
* Fix build errors that occur in certain setups (unsure exactly what is
unique about the problematic setup) due to glibc overriding
static_assert() to a variant that requires a custom message.
* Introduce actual atomics for clear/set_bit() in selftests
Documentation:
* Remove deleted ioctls from documentation
* Various fixes
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https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for 6.2
- Enable the per-vcpu dirty-ring tracking mechanism, together with an
option to keep the good old dirty log around for pages that are
dirtied by something other than a vcpu.
- Switch to the relaxed parallel fault handling, using RCU to delay
page table reclaim and giving better performance under load.
- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
option, which multi-process VMMs such as crosvm rely on.
- Merge the pKVM shadow vcpu state tracking that allows the hypervisor
to have its own view of a vcpu, keeping that state private.
- Add support for the PMUv3p5 architecture revision, bringing support
for 64bit counters on systems that support it, and fix the
no-quite-compliant CHAIN-ed counter support for the machines that
actually exist out there.
- Fix a handful of minor issues around 52bit VA/PA support (64kB pages
only) as a prefix of the oncoming support for 4kB and 16kB pages.
- Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
stage-2 faults and access tracking. You name it, we got it, we
probably broke it.
- Pick a small set of documentation and spelling fixes, because no
good merge window would be complete without those.
As a side effect, this tag also drags:
- The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
series
- A shared branch with the arm64 tree that repaints all the system
registers to match the ARM ARM's naming, and resulting in
interesting conflicts
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* kvm-arm64/dirty-ring:
: .
: Add support for the "per-vcpu dirty-ring tracking with a bitmap
: and sprinkles on top", courtesy of Gavin Shan.
:
: This branch drags the kvmarm-fixes-6.1-3 tag which was already
: merged in 6.1-rc4 so that the branch is in a working state.
: .
KVM: Push dirty information unconditionally to backup bitmap
KVM: selftests: Automate choosing dirty ring size in dirty_log_test
KVM: selftests: Clear dirty ring states between two modes in dirty_log_test
KVM: selftests: Use host page size to map ring buffer in dirty_log_test
KVM: arm64: Enable ring-based dirty memory tracking
KVM: Support dirty ring in conjunction with bitmap
KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h
KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Pull Xen-for-KVM changes from David Woodhouse:
* add support for 32-bit guests in SCHEDOP_poll
* the rest of the gfn-to-pfn cache API cleanup
"I still haven't reinstated the last of those patches to make gpc->len
immutable."
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Remove a comment about KVM_REQ_UNHALT being set by kvm_vcpu_check_block()
that was missed when KVM_REQ_UNHALT was dropped.
Fixes: c59fb1275838 ("KVM: remove KVM_REQ_UNHALT")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221201220433.31366-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When refreshing a gfn=>pfn cache, skip straight to unlocking if the cache
already valid instead of stuffing the "old" variables to turn the
unmapping outro into a nop.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Drop the @gpa param from the exported check()+refresh() helpers and limit
changing the cache's GPA to the activate path. All external users just
feed in gpc->gpa, i.e. this is a fancy nop.
Allowing users to change the GPA at check()+refresh() is dangerous as
those helpers explicitly allow concurrent calls, e.g. KVM could get into
a livelock scenario. It's also unclear as to what the expected behavior
should be if multiple tasks attempt to refresh with different GPAs.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Don't partially reinitialize a gfn=>pfn cache when activating the cache,
and instead assert that the cache is not valid during activation. Bug
the VM if the assertion fails, as use-after-free and/or data corruption
is all but guaranteed if KVM ends up with a valid-but-inactive cache.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Drop kvm_gpc_unmap() as it has no users and unclear requirements. The
API was added as part of the original gfn_to_pfn_cache support, but its
sole usage[*] was never merged. Fold the guts of kvm_gpc_unmap() into
the deactivate path and drop the API. Omit acquiring refresh_lock as
as concurrent calls to kvm_gpc_deactivate() are not allowed (this is
not enforced, e.g. via lockdep. due to it being called during vCPU
destruction).
If/when temporary unmapping makes a comeback, the desirable behavior is
likely to restrict temporary unmapping to vCPU-exclusive mappings and
require the vcpu->mutex be held to serialize unmap. Use of the
refresh_lock to protect unmapping was somewhat specuatively added by
commit 93984f19e7bc ("KVM: Fully serialize gfn=>pfn cache refresh via
mutex") to guard against concurrent unmaps, but the primary use case of
the temporary unmap, nested virtualization[*], doesn't actually need or
want concurrent unmaps.
[*] https://lore.kernel.org/all/20211210163625.2886-7-dwmw2@infradead.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Make kvm_gpc_refresh() use kvm instance cached in gfn_to_pfn_cache.
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
[sean: leave kvm_gpc_unmap() as-is]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Make hva_to_pfn_retry() use kvm instance cached in gfn_to_pfn_cache.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Make kvm_gpc_check() use kvm instance cached in gfn_to_pfn_cache.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Move the assignment of immutable properties @kvm, @vcpu, and @usage to
the initializer. Make _activate() and _deactivate() use stored values.
Note, @len is also effectively immutable for most cases, but not in the
case of the Xen runstate cache, which may be split across two pages and
the length of the first segment will depend on its address.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
[sean: handle @len in a separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
[dwmw2: acknowledge that @len can actually change for some use cases]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
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Remove the unused @kvm argument from gpc_unmap_khva().
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Formalize "gpc" as the acronym and use it in function names.
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This brings in a few important fixes for Xen emulation.
While nobody should be enabling it, the bug effectively
allows userspace to read arbitrary memory.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This brings in a few important fixes for Xen emulation.
While nobody should be enabling it, the bug effectively
allows userspace to read arbitrary memory.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In the case where a GPC is refreshed to a different location within the
same page, we didn't bother to update it. Mostly we don't need to, but
since the ->khva field also includes the offset within the page, that
does have to be updated.
Fixes: 3ba2c95ea180 ("KVM: Do not incorporate page offset into gfn=>pfn cache user address")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: stable@kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Since gfn_to_memslot() is relatively expensive, it helps to
skip it if it the memslot cannot possibly have dirty logging
enabled. In order to do this, add to struct kvm a counter
of the number of log-page memslots. While the correct value
can only be read with slots_lock taken, the NX recovery thread
is content with using an approximate value. Therefore, the
counter is an atomic_t.
Based on https://lore.kernel.org/kvm/20221027200316.2221027-2-dmatlack@google.com/
by David Matlack.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Obey kvm.halt_poll_ns in VMs not using KVM_CAP_HALT_POLL on every halt,
rather than just sampling the module parameter when the VM is first
created. This restore the original behavior of kvm.halt_poll_ns for VMs
that have not opted into KVM_CAP_HALT_POLL.
Notably, this change restores the ability for admins to disable or
change the maximum halt-polling time system wide for VMs not using
KVM_CAP_HALT_POLL.
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: acd05785e48c ("kvm: add capability for halt polling")
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20221117001657.1067231-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Avoid re-reading kvm->max_halt_poll_ns multiple times during
halt-polling except when it is explicitly useful, e.g. to check if the
max time changed across a halt. kvm->max_halt_poll_ns can be changed at
any time by userspace via KVM_CAP_HALT_POLL.
This bug is unlikely to cause any serious side-effects. In the worst
case one halt polls for shorter or longer than it should, and then is
fixed up on the next halt. Furthmore, this is still possible since
kvm->max_halt_poll_ns are not synchronized with halts.
Fixes: acd05785e48c ("kvm: add capability for halt polling")
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20221117001657.1067231-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Cap vcpu->halt_poll_ns based on the max halt polling time just before
halting, rather than after the last halt. This arguably provides better
accuracy if an admin disables halt polling in between halts, although
the improvement is nominal.
A side-effect of this change is that grow_halt_poll_ns() no longer needs
to access vcpu->kvm->max_halt_poll_ns, which will be useful in a future
commit where the max halt polling time can come from the module parameter
halt_poll_ns instead.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20221117001657.1067231-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In mark_page_dirty_in_slot(), we bail out when no running vcpu exists
and a running vcpu context is strictly required by architecture. It may
cause backwards compatible issue. Currently, saving vgic/its tables is
the only known case where no running vcpu context is expected. We may
have other unknown cases where no running vcpu context exists and it's
reported by the warning message and we bail out without pushing the
dirty information to the backup bitmap. For this, the application is
going to enable the backup bitmap for the unknown cases. However, the
dirty information can't be pushed to the backup bitmap even though the
backup bitmap is enabled for those unknown cases in the application,
until the unknown cases are added to the allowed list of non-running
vcpu context with extra code changes to the host kernel.
In order to make the new application, where the backup bitmap has been
enabled, to work with the unchanged host, we continue to push the dirty
information to the backup bitmap instead of bailing out early. With the
added check on 'memslot->dirty_bitmap' to mark_page_dirty_in_slot(), the
kernel crash is avoided silently by the combined conditions: no running
vcpu context, kvm_arch_allow_write_without_running_vcpu() returns 'true',
and the backup bitmap (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) isn't enabled
yet.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221112094322.21911-1-gshan@redhat.com
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ARM64 needs to dirty memory outside of a VCPU context when VGIC/ITS is
enabled. It's conflicting with that ring-based dirty page tracking always
requires a running VCPU context.
Introduce a new flavor of dirty ring that requires the use of both VCPU
dirty rings and a dirty bitmap. The expectation is that for non-VCPU
sources of dirty memory (such as the VGIC/ITS on arm64), KVM writes to
the dirty bitmap. Userspace should scan the dirty bitmap before migrating
the VM to the target.
Use an additional capability to advertise this behavior. The newly added
capability (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) can't be enabled before
KVM_CAP_DIRTY_LOG_RING_ACQ_REL on ARM64. In this way, the newly added
capability is treated as an extension of KVM_CAP_DIRTY_LOG_RING_ACQ_REL.
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Peter Xu <peterx@redhat.com>
Co-developed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110104914.31280-4-gshan@redhat.com
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The VCPU isn't expected to be runnable when the dirty ring becomes soft
full, until the dirty pages are harvested and the dirty ring is reset
from userspace. So there is a check in each guest's entrace to see if
the dirty ring is soft full or not. The VCPU is stopped from running if
its dirty ring has been soft full. The similar check will be needed when
the feature is going to be supported on ARM64. As Marc Zyngier suggested,
a new event will avoid pointless overhead to check the size of the dirty
ring ('vcpu->kvm->dirty_ring_size') in each guest's entrance.
Add KVM_REQ_DIRTY_RING_SOFT_FULL. The event is raised when the dirty ring
becomes soft full in kvm_dirty_ring_push(). The event is only cleared in
the check, done in the newly added helper kvm_dirty_ring_check_request().
Since the VCPU is not runnable when the dirty ring becomes soft full, the
KVM_REQ_DIRTY_RING_SOFT_FULL event is always set to prevent the VCPU from
running until the dirty pages are harvested and the dirty ring is reset by
userspace.
kvm_dirty_ring_soft_full() becomes a private function with the newly added
helper kvm_dirty_ring_check_request(). The alignment for the various event
definitions in kvm_host.h is changed to tab character by the way. In order
to avoid using 'container_of()', the argument @ring is replaced by @vcpu
in kvm_dirty_ring_push().
Link: https://lore.kernel.org/kvmarm/87lerkwtm5.wl-maz@kernel.org
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110104914.31280-2-gshan@redhat.com
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virt/kvm/irqchip.c is including "irq.h" from the arch-specific KVM source
directory (i.e. not from arch/*/include) for the sole purpose of retrieving
irqchip_in_kernel.
Making the function inline in a header that is already included,
such as asm/kvm_host.h, is not possible because it needs to look at
struct kvm which is defined after asm/kvm_host.h is included. So add a
kvm_arch_irqchip_in_kernel non-inline function; irqchip_in_kernel() is
only performance critical on arm64 and x86, and the non-inline function
is enough on all other architectures.
irq.h can then be deleted from all architectures except x86.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a new "interruptible" flag showing that the caller is willing to be
interrupted by signals during the __gfn_to_pfn_memslot() request. Wire it
up with a FOLL_INTERRUPTIBLE flag that we've just introduced.
This prepares KVM to be able to respond to SIGUSR1 (for QEMU that's the
SIGIPI) even during e.g. handling an userfaultfd page fault.
No functional change intended.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221011195809.557016-4-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a new pfn error to show that we've got a pending signal to handle
during hva_to_pfn_slow() procedure (of -EINTR retval).
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221011195809.557016-3-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
* Fix the pKVM stage-1 walker erronously using the stage-2 accessor
* Correctly convert vcpu->kvm to a hyp pointer when generating
an exception in a nVHE+MTE configuration
* Check that KVM_CAP_DIRTY_LOG_* are valid before enabling them
* Fix SMPRI_EL1/TPIDR2_EL0 trapping on VHE
* Document the boot requirements for FGT when entering the kernel
at EL1
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There are two capabilities related to ring-based dirty page tracking:
KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Both are
supported by x86. However, arm64 supports KVM_CAP_DIRTY_LOG_RING_ACQ_REL
only when the feature is supported on arm64. The userspace doesn't have
to enable the advertised capability, meaning KVM_CAP_DIRTY_LOG_RING can
be enabled on arm64 by userspace and it's wrong.
Fix it by double checking if the capability has been advertised prior to
enabling it. It's rejected to enable the capability if it hasn't been
advertised.
Fixes: 17601bfed909 ("KVM: Add KVM_CAP_DIRTY_LOG_RING_ACQ_REL capability and config option")
Reported-by: Sean Christopherson <seanjc@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221031003621.164306-4-gshan@redhat.com
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Reject kvm_gpc_check() and kvm_gpc_refresh() if the cache is inactive.
Not checking the active flag during refresh is particularly egregious, as
KVM can end up with a valid, inactive cache, which can lead to a variety
of use-after-free bugs, e.g. consuming a NULL kernel pointer or missing
an mmu_notifier invalidation due to the cache not being on the list of
gfns to invalidate.
Note, "active" needs to be set if and only if the cache is on the list
of caches, i.e. is reachable via mmu_notifier events. If a relevant
mmu_notifier event occurs while the cache is "active" but not on the
list, KVM will not acquire the cache's lock and so will not serailize
the mmu_notifier event with active users and/or kvm_gpc_refresh().
A race between KVM_XEN_ATTR_TYPE_SHARED_INFO and KVM_XEN_HVM_EVTCHN_SEND
can be exploited to trigger the bug.
1. Deactivate shinfo cache:
kvm_xen_hvm_set_attr
case KVM_XEN_ATTR_TYPE_SHARED_INFO
kvm_gpc_deactivate
kvm_gpc_unmap
gpc->valid = false
gpc->khva = NULL
gpc->active = false
Result: active = false, valid = false
2. Cause cache refresh:
kvm_arch_vm_ioctl
case KVM_XEN_HVM_EVTCHN_SEND
kvm_xen_hvm_evtchn_send
kvm_xen_set_evtchn
kvm_xen_set_evtchn_fast
kvm_gpc_check
return -EWOULDBLOCK because !gpc->valid
kvm_xen_set_evtchn_fast
return -EWOULDBLOCK
kvm_gpc_refresh
hva_to_pfn_retry
gpc->valid = true
gpc->khva = not NULL
Result: active = false, valid = true
3. Race ioctl KVM_XEN_HVM_EVTCHN_SEND against ioctl
KVM_XEN_ATTR_TYPE_SHARED_INFO:
kvm_arch_vm_ioctl
case KVM_XEN_HVM_EVTCHN_SEND
kvm_xen_hvm_evtchn_send
kvm_xen_set_evtchn
kvm_xen_set_evtchn_fast
read_lock gpc->lock
kvm_xen_hvm_set_attr case
KVM_XEN_ATTR_TYPE_SHARED_INFO
mutex_lock kvm->lock
kvm_xen_shared_info_init
kvm_gpc_activate
gpc->khva = NULL
kvm_gpc_check
[ Check passes because gpc->valid is
still true, even though gpc->khva
is already NULL. ]
shinfo = gpc->khva
pending_bits = shinfo->evtchn_pending
CRASH: test_and_set_bit(..., pending_bits)
Fixes: 982ed0de4753 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Reported-by: : Michal Luczaj <mhal@rbox.co>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013211234.1318131-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Move the gfn_to_pfn_cache lock initialization to another helper and
call the new helper during VM/vCPU creation. There are race
conditions possible due to kvm_gfn_to_pfn_cache_init()'s
ability to re-initialize the cache's locks.
For example: a race between ioctl(KVM_XEN_HVM_EVTCHN_SEND) and
kvm_gfn_to_pfn_cache_init() leads to a corrupted shinfo gpc lock.
(thread 1) | (thread 2)
|
kvm_xen_set_evtchn_fast |
read_lock_irqsave(&gpc->lock, ...) |
| kvm_gfn_to_pfn_cache_init
| rwlock_init(&gpc->lock)
read_unlock_irqrestore(&gpc->lock, ...) |
Rename "cache_init" and "cache_destroy" to activate+deactivate to
avoid implying that the cache really is destroyed/freed.
Note, there more races in the newly named kvm_gpc_activate() that will
be addressed separately.
Fixes: 982ed0de4753 ("KVM: Reinstate gfn_to_pfn_cache with invalidation support")
Cc: stable@vger.kernel.org
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
[sean: call out that this is a bug fix]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221013211234.1318131-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Although simple_attr_open() fails only with -ENOMEM with current code
base, it would be nicer to return retval of simple_attr_open() directly
in kvm_debugfs_open().
No functional change intended.
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
Message-Id: <69d64d93accd1f33691b8a383ae555baee80f943.1665975828.git.houwenlong.hwl@antgroup.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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We will introduce the first architecture specific compat vm ioctl in the
next patch. Add all necessary boilerplate to allow architectures to
override compat vm ioctls when necessary.
Signed-off-by: Alexander Graf <graf@amazon.com>
Message-Id: <20221017184541.2658-2-graf@amazon.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Pull VFIO updates from Alex Williamson:
- Prune private items from vfio_pci_core.h to a new internal header,
fix missed function rename, and refactor vfio-pci interrupt defines
(Jason Gunthorpe)
- Create consistent naming and handling of ioctls with a function per
ioctl for vfio-pci and vfio group handling, use proper type args
where available (Jason Gunthorpe)
- Implement a set of low power device feature ioctls allowing userspace
to make use of power states such as D3cold where supported (Abhishek
Sahu)
- Remove device counter on vfio groups, which had restricted the page
pinning interface to singleton groups to account for limitations in
the type1 IOMMU backend. Document usage as limited to emulated IOMMU
devices, ie. traditional mdev devices where this restriction is
consistent (Jason Gunthorpe)
- Correct function prefix in hisi_acc driver incurred during previous
refactoring (Shameer Kolothum)
- Correct typo and remove redundant warning triggers in vfio-fsl driver
(Christophe JAILLET)
- Introduce device level DMA dirty tracking uAPI and implementation in
the mlx5 variant driver (Yishai Hadas & Joao Martins)
- Move much of the vfio_device life cycle management into vfio core,
simplifying and avoiding duplication across drivers. This also
facilitates adding a struct device to vfio_device which begins the
introduction of device rather than group level user support and fills
a gap allowing userspace identify devices as vfio capable without
implicit knowledge of the driver (Kevin Tian & Yi Liu)
- Split vfio container handling to a separate file, creating a more
well defined API between the core and container code, masking IOMMU
backend implementation from the core, allowing for an easier future
transition to an iommufd based implementation of the same (Jason
Gunthorpe)
- Attempt to resolve race accessing the iommu_group for a device
between vfio releasing DMA ownership and removal of the device from
the IOMMU driver. Follow-up with support to allow vfio_group to exist
with NULL iommu_group pointer to support existing userspace use cases
of holding the group file open (Jason Gunthorpe)
- Fix error code and hi/lo register manipulation issues in the hisi_acc
variant driver, along with various code cleanups (Longfang Liu)
- Fix a prior regression in GVT-g group teardown, resulting in
unreleased resources (Jason Gunthorpe)
- A significant cleanup and simplification of the mdev interface,
consolidating much of the open coded per driver sysfs interface
support into the mdev core (Christoph Hellwig)
- Simplification of tracking and locking around vfio_groups that fall
out from previous refactoring (Jason Gunthorpe)
- Replace trivial open coded f_ops tests with new helper (Alex
Williamson)
* tag 'vfio-v6.1-rc1' of https://github.com/awilliam/linux-vfio: (77 commits)
vfio: More vfio_file_is_group() use cases
vfio: Make the group FD disassociate from the iommu_group
vfio: Hold a reference to the iommu_group in kvm for SPAPR
vfio: Add vfio_file_is_group()
vfio: Change vfio_group->group_rwsem to a mutex
vfio: Remove the vfio_group->users and users_comp
vfio/mdev: add mdev available instance checking to the core
vfio/mdev: consolidate all the description sysfs into the core code
vfio/mdev: consolidate all the available_instance sysfs into the core code
vfio/mdev: consolidate all the name sysfs into the core code
vfio/mdev: consolidate all the device_api sysfs into the core code
vfio/mdev: remove mtype_get_parent_dev
vfio/mdev: remove mdev_parent_dev
vfio/mdev: unexport mdev_bus_type
vfio/mdev: remove mdev_from_dev
vfio/mdev: simplify mdev_type handling
vfio/mdev: embedd struct mdev_parent in the parent data structure
vfio/mdev: make mdev.h standalone includable
drm/i915/gvt: simplify vgpu configuration management
drm/i915/gvt: fix a memory leak in intel_gvt_init_vgpu_types
...
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SPAPR exists completely outside the normal iommu driver framework, the
groups it creates are fake and are only created to enable VFIO's uAPI.
Thus, it does not need to follow the iommu core rule that the iommu_group
will only be touched while a driver is attached.
Carry a group reference into KVM and have KVM directly manage the lifetime
of this object independently of VFIO. This means KVM no longer relies on
the vfio group file being valid to maintain the group reference.
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/2-v2-15417f29324e+1c-vfio_group_disassociate_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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