From 6ea567ca003ab05adef28459bde1495a250dd7b7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 6 Jan 2023 01:12:50 +0000 Subject: [PATCH] KVM: x86: Explicitly skip optimized logical map setup if vCPU's LDR==0 Explicitly skip the optimized map setup if the vCPU's LDR is '0', i.e. if the vCPU will never respond to logical mode interrupts. KVM already skips setup in this case, but relies on kvm_apic_map_get_logical_dest() to generate mask==0. KVM still needs the mask=0 check as a non-zero LDR can yield mask==0 depending on the mode, but explicitly handling the LDR will make it simpler to clean up the logical mode tracking in the future. No functional change intended. Reviewed-by: Maxim Levitsky Signed-off-by: Sean Christopherson Message-Id: <20230106011306.85230-18-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 355ea688df4a6..2aee712e42bb4 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -286,10 +286,12 @@ void kvm_recalculate_apic_map(struct kvm *kvm) continue; ldr = kvm_lapic_get_reg(apic, APIC_LDR); + if (!ldr) + continue; if (apic_x2apic_mode(apic)) { new->mode |= KVM_APIC_MODE_X2APIC; - } else if (ldr) { + } else { ldr = GET_APIC_LOGICAL_ID(ldr); if (kvm_lapic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT) new->mode |= KVM_APIC_MODE_XAPIC_FLAT; -- 2.30.2