From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH] KVM: x86: use correct APIC ID on x2APIC transition Date: Fri, 22 May 2015 18:45:11 +0200 Message-ID: <1432313111-18829-1-git-send-email-rkrcmar@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org, Paolo Bonzini To: linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org SDM April 2015, 10.12.5 State Changes From xAPIC Mode to x2APIC Mode =E2=80=A2 Any APIC ID value written to the memory-mapped local APIC ID = register is not preserved. =46ix it by sourcing vcpu_id (=3D initial APIC ID) instead of memory-ma= pped APIC ID. Proper use of apic functions would result in two calls to recalculate_apic_map(), so this patch makes a new helper. Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 --- arch/x86/kvm/lapic.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index dc5b57bb1f76..c2a7d8a7a414 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -240,6 +240,15 @@ static inline void kvm_apic_set_ldr(struct kvm_lap= ic *apic, u32 id) recalculate_apic_map(apic->vcpu->kvm); } =20 +static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u8 i= d) +{ + u32 ldr =3D ((id >> 4) << 16) | (1 << (id & 0xf)); + + apic_set_reg(apic, APIC_ID, id << 24); + apic_set_reg(apic, APIC_LDR, ldr); + recalculate_apic_map(apic->vcpu->kvm); +} + static inline int apic_lvt_enabled(struct kvm_lapic *apic, int lvt_typ= e) { return !(kvm_apic_get_reg(apic, lvt_type) & APIC_LVT_MASKED); @@ -1538,9 +1547,7 @@ void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u6= 4 value) =20 if ((old_value ^ value) & X2APIC_ENABLE) { if (value & X2APIC_ENABLE) { - u32 id =3D kvm_apic_id(apic); - u32 ldr =3D ((id >> 4) << 16) | (1 << (id & 0xf)); - kvm_apic_set_ldr(apic, ldr); + kvm_apic_set_x2apic_id(apic, vcpu->vcpu_id); kvm_x86_ops->set_virtual_x2apic_mode(vcpu, true); } else kvm_x86_ops->set_virtual_x2apic_mode(vcpu, false); --=20 2.4.1