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authorJoao Martins <joao.m.martins@oracle.com>2019-11-11 17:20:10 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2019-11-12 10:17:40 +0100
commit9482ae458b7ae1b47c76333592bbe013d47e579f (patch)
treed9b42638af4072a7b4fdcd478f26e0aec628b53e /arch
parentd9ff2744eea21aac43fafa22f6178541bfe2e3d8 (diff)
downloadlinux-9482ae458b7ae1b47c76333592bbe013d47e579f.tar.bz2
KVM: VMX: Consider PID.PIR to determine if vCPU has pending interrupts
Commit 17e433b54393 ("KVM: Fix leak vCPU's VMCS value into other pCPU") introduced vmx_dy_apicv_has_pending_interrupt() in order to determine if a vCPU have a pending posted interrupt. This routine is used by kvm_vcpu_on_spin() when searching for a a new runnable vCPU to schedule on pCPU instead of a vCPU doing busy loop. vmx_dy_apicv_has_pending_interrupt() determines if a vCPU has a pending posted interrupt solely based on PID.ON. However, when a vCPU is preempted, vmx_vcpu_pi_put() sets PID.SN which cause raised posted interrupts to only set bit in PID.PIR without setting PID.ON (and without sending notification vector), as depicted in VT-d manual section 5.2.3 "Interrupt-Posting Hardware Operation". Therefore, checking PID.ON is insufficient to determine if a vCPU has pending posted interrupts and instead we should also check if there is some bit set on PID.PIR if PID.SN=1. Fixes: 17e433b54393 ("KVM: Fix leak vCPU's VMCS value into other pCPU") Reviewed-by: Jagannathan Raman <jag.raman@oracle.com> Co-developed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx/vmx.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f53b0c74f7c8..623914dc3a3e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6167,7 +6167,11 @@ static int vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
static bool vmx_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
{
- return pi_test_on(vcpu_to_pi_desc(vcpu));
+ struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
+
+ return pi_test_on(pi_desc) ||
+ (pi_test_sn(pi_desc) &&
+ !bitmap_empty((unsigned long *)pi_desc->pir, NR_VECTORS));
}
static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)