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KVM: VMX: Assert that IRQs are disabled when putting vCPU on PI wakeup list

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Assert that IRQs are already disabled when putting a vCPU on a CPU's PI
wakeup list, as opposed to saving/disabling+restoring IRQs.  KVM relies on
IRQs being disabled until the vCPU task is fully scheduled out, i.e. until
the scheduler has dropped all of its per-CPU locks (e.g. for the runqueue),
as attempting to wake the task while it's being scheduled out could lead
to deadlock.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Message-ID: <20250401154727.835231-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2025-04-01 08:47:26 -07:00 committed by Paolo Bonzini
parent 782f9feaa9
commit 6bad6ecc63
1 changed files with 1 additions and 4 deletions
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5
arch/x86/kvm/vmx/posted_intr.c
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@ -148,9 +148,8 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu)
struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct pi_desc old, new;
unsigned long flags;
local_irq_save(flags);
lockdep_assert_irqs_disabled();
raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, vcpu->cpu));
list_add_tail(&vmx->pi_wakeup_list,
@ -176,8 +175,6 @@ static void pi_enable_wakeup_handler(struct kvm_vcpu *vcpu)
*/
if (pi_test_on(&new))
__apic_send_IPI_self(POSTED_INTR_WAKEUP_VECTOR);
local_irq_restore(flags);
}
static bool vmx_needs_pi_wakeup(struct kvm_vcpu *vcpu)