[PW_SID:958644] KVM: lockdep improvements#361
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Use mutex_trylock_nest_lock instead of mutex_trylock when locking all vCPUs
of a VM, to avoid triggering a lockdep warning, if the VM is configured to
have more than MAX_LOCK_DEPTH vCPUs.
This fixes the following false lockdep warning:
[ 328.171264] BUG: MAX_LOCK_DEPTH too low!
[ 328.175227] turning off the locking correctness validator.
[ 328.180726] Please attach the output of /proc/lock_stat to the bug report
[ 328.187531] depth: 48 max: 48!
[ 328.190678] 48 locks held by qemu-kvm/11664:
[ 328.194957] #0: ffff800086de5ba0 (&kvm->lock){+.+.}-{3:3}, at: kvm_ioctl_create_device+0x174/0x5b0
[ 328.204048] #1: ffff0800e78800b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.212521] #2: ffff07ffeee51e98 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.220991] #3: ffff0800dc7d80b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.229463] #4: ffff07ffe0c980b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.237934] #5: ffff0800a3883c78 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
[ 328.246405] #6: ffff07fffbe480b8 (&vcpu->mutex){+.+.}-{3:3}, at: lock_all_vcpus+0x16c/0x2a0
Since the locking of all vCPUs is a primitive that can be useful in other
architectures that are supported by KVM, also move the code to kvm_main.c
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
Use the kvm_trylock_all_vcpus()/unlock_all_vcpus() instead of riscv's own implementation, to avoid triggering a lockdep warning, if the VM is configured to have more than MAX_LOCK_DEPTH vCPUs. Compile tested only. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
KVM's SEV intra-host migration code needs to lock all vCPUs of the source and the target VM, before it proceeds with the migration. The number of vCPUs that belong to each VM is not bounded by anything except a self-imposed KVM limit of CONFIG_KVM_MAX_NR_VCPUS vCPUs which is significantly larger than the depth of lockdep's lock stack. Luckily, the locks in both of the cases mentioned above, are held under the 'kvm->lock' of each VM, which means that we can use the little known lockdep feature called a "nest_lock" to support this use case in a cleaner way, compared to the way it's currently done. Implement and expose 'mutex_lock_killable_nest_lock' for this purpose. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
Implement kvm_lock_all_vcpus() and use it instead of
sev own sev_{lock|unlock}_vcpus_for_migration().
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 1: "[v3,1/4] arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 2: "[v3,2/4] RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 3: "[v3,3/4] locking/mutex: implement mutex_lock_killable_nest_lock" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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Patch 4: "[v3,4/4] x86: KVM: SEV: implement kvm_lock_all_vcpus and use it" |
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PR for series 958644 applied to workflow__riscv__fixes
Name: KVM: lockdep improvements
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=958644
Version: 3