From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Date: Fri, 18 Nov 2016 14:59:25 +0000 Subject: Re: [PATCH 10/13] KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9 Message-Id: <87vavkn8ua.fsf@linux.vnet.ibm.com> List-Id: References: <1479454122-26994-1-git-send-email-paulus@ozlabs.org> <1479454122-26994-11-git-send-email-paulus@ozlabs.org> In-Reply-To: <1479454122-26994-11-git-send-email-paulus@ozlabs.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Paul Mackerras , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@ozlabs.org Paul Mackerras writes: > On POWER9, the msgsnd instruction is able to send interrupts to > other cores, as well as other threads on the local core. Since > msgsnd is generally simpler and faster than sending an IPI via the > XICS, we use msgsnd for all IPIs sent by KVM on POWER9. > > Signed-off-by: Paul Mackerras > --- > arch/powerpc/kvm/book3s_hv.c | 11 ++++++++++- > arch/powerpc/kvm/book3s_hv_builtin.c | 10 ++++++++-- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 8395a7f..ace89df 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -147,12 +147,21 @@ static inline struct kvm_vcpu *next_runnable_thread(struct kvmppc_vcore *vc, > > static bool kvmppc_ipi_thread(int cpu) > { > + unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > + > + /* On POWER9 we can use msgsnd to IPI any cpu */ > + if (cpu_has_feature(CPU_FTR_ARCH_300)) { > + msg |= get_hard_smp_processor_id(cpu); > + smp_mb(); > + __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > + return true; > + } > + > /* On POWER8 for IPIs to threads in the same core, use msgsnd */ > if (cpu_has_feature(CPU_FTR_ARCH_207S)) { > preempt_disable(); > if (cpu_first_thread_sibling(cpu) = > cpu_first_thread_sibling(smp_processor_id())) { > - unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > msg |= cpu_thread_in_core(cpu); > smp_mb(); > __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c > index 0c84d6b..37ed045 100644 > --- a/arch/powerpc/kvm/book3s_hv_builtin.c > +++ b/arch/powerpc/kvm/book3s_hv_builtin.c > @@ -205,12 +205,18 @@ static inline void rm_writeb(unsigned long paddr, u8 val) > void kvmhv_rm_send_ipi(int cpu) > { > unsigned long xics_phys; > + unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > > - /* On POWER8 for IPIs to threads in the same core, use msgsnd */ > + /* On POWER9 we can use msgsnd for any destination cpu. */ > + if (cpu_has_feature(CPU_FTR_ARCH_300)) { > + msg |= get_hard_smp_processor_id(cpu); > + __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > + return; Do we need a "sync" there before msgsnd ? > + } > + /* On POWER8 for IPIs to threads in the same core, use msgsnd. */ > if (cpu_has_feature(CPU_FTR_ARCH_207S) && > cpu_first_thread_sibling(cpu) = > cpu_first_thread_sibling(raw_smp_processor_id())) { > - unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > msg |= cpu_thread_in_core(cpu); > __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > return; > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3tL1Cl6Bm9zDvyJ for ; Sat, 19 Nov 2016 01:51:31 +1100 (AEDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3tL1Cl23LVz9t3K for ; Sat, 19 Nov 2016 01:51:31 +1100 (AEDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAIEmo0Y070970 for ; Fri, 18 Nov 2016 09:51:29 -0500 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0b-001b2d01.pphosted.com with ESMTP id 26stsnsbcn-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 18 Nov 2016 09:51:28 -0500 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 18 Nov 2016 09:51:28 -0500 From: "Aneesh Kumar K.V" To: Paul Mackerras , kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@ozlabs.org Subject: Re: [PATCH 10/13] KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9 In-Reply-To: <1479454122-26994-11-git-send-email-paulus@ozlabs.org> References: <1479454122-26994-1-git-send-email-paulus@ozlabs.org> <1479454122-26994-11-git-send-email-paulus@ozlabs.org> Date: Fri, 18 Nov 2016 20:17:25 +0530 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87vavkn8ua.fsf@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Paul Mackerras writes: > On POWER9, the msgsnd instruction is able to send interrupts to > other cores, as well as other threads on the local core. Since > msgsnd is generally simpler and faster than sending an IPI via the > XICS, we use msgsnd for all IPIs sent by KVM on POWER9. > > Signed-off-by: Paul Mackerras > --- > arch/powerpc/kvm/book3s_hv.c | 11 ++++++++++- > arch/powerpc/kvm/book3s_hv_builtin.c | 10 ++++++++-- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 8395a7f..ace89df 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -147,12 +147,21 @@ static inline struct kvm_vcpu *next_runnable_thread(struct kvmppc_vcore *vc, > > static bool kvmppc_ipi_thread(int cpu) > { > + unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > + > + /* On POWER9 we can use msgsnd to IPI any cpu */ > + if (cpu_has_feature(CPU_FTR_ARCH_300)) { > + msg |= get_hard_smp_processor_id(cpu); > + smp_mb(); > + __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > + return true; > + } > + > /* On POWER8 for IPIs to threads in the same core, use msgsnd */ > if (cpu_has_feature(CPU_FTR_ARCH_207S)) { > preempt_disable(); > if (cpu_first_thread_sibling(cpu) == > cpu_first_thread_sibling(smp_processor_id())) { > - unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > msg |= cpu_thread_in_core(cpu); > smp_mb(); > __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c > index 0c84d6b..37ed045 100644 > --- a/arch/powerpc/kvm/book3s_hv_builtin.c > +++ b/arch/powerpc/kvm/book3s_hv_builtin.c > @@ -205,12 +205,18 @@ static inline void rm_writeb(unsigned long paddr, u8 val) > void kvmhv_rm_send_ipi(int cpu) > { > unsigned long xics_phys; > + unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > > - /* On POWER8 for IPIs to threads in the same core, use msgsnd */ > + /* On POWER9 we can use msgsnd for any destination cpu. */ > + if (cpu_has_feature(CPU_FTR_ARCH_300)) { > + msg |= get_hard_smp_processor_id(cpu); > + __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > + return; Do we need a "sync" there before msgsnd ? > + } > + /* On POWER8 for IPIs to threads in the same core, use msgsnd. */ > if (cpu_has_feature(CPU_FTR_ARCH_207S) && > cpu_first_thread_sibling(cpu) == > cpu_first_thread_sibling(raw_smp_processor_id())) { > - unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); > msg |= cpu_thread_in_core(cpu); > __asm__ __volatile__ (PPC_MSGSND(%0) : : "r" (msg)); > return; > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html