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| author | David Matlack <dmatlack@google.com> | 2024-05-03 20:17:32 +0200 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-06-18 18:20:01 +0200 |
| commit | a6816314af5749cd88944bfdceb270c627cdf348 (patch) | |
| tree | e082018db936c3d3be6219608524d8a508b1c259 /arch/s390/kvm/kvm-s390.c | |
| parent | KVM: selftests: Test vCPU boot IDs above 2^32 and MAX_VCPU_ID (diff) | |
| download | linux-a6816314af5749cd88944bfdceb270c627cdf348.tar.xz linux-a6816314af5749cd88944bfdceb270c627cdf348.zip | |
KVM: Introduce vcpu->wants_to_run
Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run
loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit
was not set.
Replace all references to vcpu->run->immediate_exit with
!vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a
malicious userspace could invoked KVM_RUN with immediate_exit=true and
then after KVM reads it to set wants_to_run=false, flip it to false.
This would result in the vCPU running in KVM_RUN with
wants_to_run=false. This wouldn't cause any real bugs today but is a
dangerous landmine.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 4641083ee100..5da808976085 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -5026,7 +5026,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) if (vcpu->kvm->arch.pv.dumping) return -EINVAL; - if (kvm_run->immediate_exit) + if (!vcpu->wants_to_run) return -EINTR; if (kvm_run->kvm_valid_regs & ~KVM_SYNC_S390_VALID_FIELDS || |