diff options
| author | Sean Christopherson <seanjc@google.com> | 2026-08-06 14:46:18 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-09-11 12:06:05 -0700 |
| commit | 8cd280282d1239bca68f8c3632ef1ac8556a396b (patch) | |
| tree | 2d84f45da418c8292c3b8329d8dbd6d793ff8d92 /include/linux | |
| parent | f13368e0acffd6d6289629705cb821d921104725 (diff) | |
KVM: Never clear KVM_REQ_VM_DEAD from a vCPU's requests
Use kvm_test_request() instead of kvm_check_request() when querying
KVM_REQ_VM_DEAD, i.e. don't clear KVM_REQ_VM_DEAD, as the entire purpose
of KVM_REQ_VM_DEAD is to prevent the vCPU from enterring the guest ever
again, even if userspace insists on redoing KVM_RUN.
Ensuring KVM_REQ_VM_DEAD is never cleared will allow relaxing KVM's rule
that ioctls can't be invoked on dead VMs, to only disallow ioctls if the
VM is bugged, i.e. if KVM hit a KVM_BUG_ON().
Opportunistically add compile-time assertions to guard against clearing
KVM_REQ_VM_DEAD through the standard APIs.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20260806214618.82180-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/kvm_host.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 03bfc92864b6..cf7fe835c4ad 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2324,13 +2324,18 @@ static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu) return test_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests); } -static inline void kvm_clear_request(int req, struct kvm_vcpu *vcpu) +static __always_inline void kvm_clear_request(int req, struct kvm_vcpu *vcpu) { + BUILD_BUG_ON(req == KVM_REQ_VM_DEAD); + clear_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests); } -static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) +static __always_inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu) { + /* Once a VM is dead, it needs to stay dead. */ + BUILD_BUG_ON(req == KVM_REQ_VM_DEAD); + if (kvm_test_request(req, vcpu)) { kvm_clear_request(req, vcpu); |