From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH v3 12/14] KVM: x86: add a flag to disable KVM x2apic broadcast quirk Date: Tue, 12 Jul 2016 22:09:28 +0200 Message-ID: <20160712200930.32143-13-rkrcmar@redhat.com> References: <20160712200930.32143-1-rkrcmar@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Paolo Bonzini , "Lan, Tianyu" , Igor Mammedov , Jan Kiszka , Peter Xu , Yang Zhang To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52055 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752127AbcGLUKm (ORCPT ); Tue, 12 Jul 2016 16:10:42 -0400 In-Reply-To: <20160712200930.32143-1-rkrcmar@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Add KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK as a feature flag to KVM_CAP_X2APIC_API. The quirk made KVM interpret 0xff as a broadcast even in x2APIC mode. The enableable capability is needed in order to support standard x2APIC= and remain backward compatible. Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 --- v3: new Documentation/virtual/kvm/api.txt | 5 +++++ arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/lapic.c | 40 +++++++++++++++++++++++++++++--= -------- arch/x86/kvm/x86.c | 5 ++++- include/uapi/linux/kvm.h | 1 + 5 files changed, 41 insertions(+), 11 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/= kvm/api.txt index 10e2bf903e57..c2753ff4a499 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -3843,12 +3843,17 @@ Returns: 0 on success, -EINVAL when args[0] con= tains invalid features Valid feature flags in args[0] are =20 #define KVM_X2APIC_API_USE_32BIT_FORMAT (1ULL << 0) +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) =20 Enabling KVM_X2APIC_API_USE_32BIT_FORMAT changes the behavior of KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC,= allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their respectiv= e sections. =20 +KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to w= ork in +logical mode or with more than 255 VCPUs. A KVM quirk treats 0xff as = a +broadcast even in x2APIC mode (a consequence of allowing physical x2AP= IC +without interrupt remapping). =20 =20 8. Other capabilities. diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm= _host.h index f13522f85a1d..25bf9d627c15 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -784,6 +784,7 @@ struct kvm_arch { struct page *avic_physical_id_table_page; =20 bool x2apic_format; + bool x2apic_broadcast_quirk_disabled; }; =20 struct kvm_vm_stat { diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index d27a7829a4ce..46f1d1c93420 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -619,14 +619,17 @@ static bool kvm_apic_match_logical_addr(struct kv= m_lapic *apic, u32 mda) /* KVM APIC implementation has two quirks * - dest always begins at 0 while xAPIC MDA has offset 24, * - IOxAPIC messages have to be delivered (directly) to x2APIC. + * + * The broadcast quirk can be disabled with KVM_CAP_X2APIC_API. */ -static u32 kvm_apic_mda(unsigned int dest_id, struct kvm_lapic *source= , - struct kvm_lapic *target= ) +static u32 kvm_apic_mda(struct kvm_vcpu *vcpu, unsigned int dest_id, + struct kvm_lapic *source, struct kvm_lapic *target) { bool ipi =3D source !=3D NULL; bool x2apic_mda =3D apic_x2apic_mode(ipi ? source : target); =20 - if (!ipi && dest_id =3D=3D APIC_BROADCAST && x2apic_mda) + if (!vcpu->kvm->arch.x2apic_broadcast_quirk_disabled && + !ipi && dest_id =3D=3D APIC_BROADCAST && x2apic_mda) return X2APIC_BROADCAST; =20 return x2apic_mda ? dest_id : SET_APIC_DEST_FIELD(dest_id); @@ -636,7 +639,7 @@ bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, str= uct kvm_lapic *source, int short_hand, unsigned int dest, int dest_mode) { struct kvm_lapic *target =3D vcpu->arch.apic; - u32 mda =3D kvm_apic_mda(dest, source, target); + u32 mda =3D kvm_apic_mda(vcpu, dest, source, target); =20 apic_debug("target %p, source %p, dest 0x%x, " "dest_mode 0x%x, short_hand 0x%x\n", @@ -688,6 +691,28 @@ static void kvm_apic_disabled_lapic_found(struct k= vm *kvm) } } =20 +static bool kvm_apic_map_need_slowpath(struct kvm *kvm, struct kvm_lap= ic **src, + struct kvm_lapic_irq *irq, struct kvm_apic_map *map) +{ + if (!map) + return true; + + if (kvm->arch.x2apic_broadcast_quirk_disabled) { + if ((irq->dest_id =3D=3D APIC_BROADCAST && + map->mode !=3D KVM_APIC_MODE_X2APIC)) + return true; + if (irq->dest_id =3D=3D X2APIC_BROADCAST) + return true; + } else { + bool x2apic_ipi =3D src && *src && apic_x2apic_mode(*src); + if (irq->dest_id =3D=3D (x2apic_ipi ? + X2APIC_BROADCAST : APIC_BROADCAST)) + return true; + } + + return false; +} + /* Return true if the interrupt can be handled by using *bitmap as ind= ex mask * for valid destinations in *dst array. * Return false if kvm_apic_map_get_dest_lapic did nothing useful. @@ -701,7 +726,6 @@ static inline bool kvm_apic_map_get_dest_lapic(stru= ct kvm *kvm, unsigned long *bitmap) { int i, lowest; - bool x2apic_ipi; =20 if (irq->shorthand =3D=3D APIC_DEST_SELF && src) { *dst =3D src; @@ -710,11 +734,7 @@ static inline bool kvm_apic_map_get_dest_lapic(str= uct kvm *kvm, } else if (irq->shorthand) return false; =20 - x2apic_ipi =3D src && *src && apic_x2apic_mode(*src); - if (irq->dest_id =3D=3D (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCA= ST)) - return false; - - if (!map) + if (kvm_apic_map_need_slowpath(kvm, src, irq, map)) return false; =20 if (irq->dest_mode =3D=3D APIC_DEST_PHYSICAL) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 330276315daa..4bab85f82a96 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -90,7 +90,8 @@ static u64 __read_mostly efer_reserved_bits =3D ~((u6= 4)EFER_SCE); #define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU =20 -#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_FORMAT) +#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_FORMAT | = \ + KVM_X2APIC_API_DISABLE_BROADCAST_Q= UIRK) =20 static void update_cr8_intercept(struct kvm_vcpu *vcpu); static void process_nmi(struct kvm_vcpu *vcpu); @@ -3811,6 +3812,8 @@ split_irqchip_unlock: =20 if (cap->args[0] & KVM_X2APIC_API_USE_32BIT_FORMAT) kvm->arch.x2apic_format =3D true; + if (cap->args[0] & KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) + kvm->arch.x2apic_broadcast_quirk_disabled =3D true; =20 r =3D 0; break; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index b6de3febabaa..13b30dfd93b2 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1315,5 +1315,6 @@ struct kvm_assigned_msix_entry { }; =20 #define KVM_X2APIC_API_USE_32BIT_FORMAT (1ULL << 0) +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) =20 #endif /* __LINUX_KVM_H */ --=20 2.9.0