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Wed, 9 Mar 2022 14:41:32 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9FA75C6059; Wed, 9 Mar 2022 14:41:32 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 09A75C6057; Wed, 9 Mar 2022 14:41:32 +0000 (GMT) Received: from localhost (unknown [9.211.59.35]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTPS; Wed, 9 Mar 2022 14:41:31 +0000 (GMT) From: Fabiano Rosas To: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 3/6] KVM: PPC: Book3S HV P9: Move cede logic out of XIVE escalation rearming In-Reply-To: <20220303053315.1056880-4-npiggin@gmail.com> References: <20220303053315.1056880-1-npiggin@gmail.com> <20220303053315.1056880-4-npiggin@gmail.com> Date: Wed, 09 Mar 2022 11:41:30 -0300 Message-ID: <878rtjb339.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-GUID: IaNuoO_m1b8zuaFVUejwDXHp3UbogsjH X-Proofpoint-ORIG-GUID: irD-rAxIf_6zA_gPG97VDlo8mjwqTkiG X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-09_05,2022-03-09_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxlogscore=999 spamscore=0 mlxscore=0 impostorscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203090081 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?Q?C=C3=A9dric?= Le Goater , Nicholas Piggin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Nicholas Piggin writes: > Move the cede abort logic out of xive escalation rearming and into > the caller to prepare for handling a similar case with nested guest > entry. > > Signed-off-by: Nicholas Piggin > --- > arch/powerpc/include/asm/kvm_ppc.h | 4 ++-- > arch/powerpc/kvm/book3s_hv.c | 10 ++++++++-- > arch/powerpc/kvm/book3s_xive.c | 9 ++++++--- > 3 files changed, 16 insertions(+), 7 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h > index a14dbcd1b8ce..94fa5f246657 100644 > --- a/arch/powerpc/include/asm/kvm_ppc.h > +++ b/arch/powerpc/include/asm/kvm_ppc.h > @@ -671,7 +671,7 @@ extern int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, > int level, bool line_status); > extern void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu); > extern void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu); > -extern void kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu); > +extern bool kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu); > > static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu) > { > @@ -709,7 +709,7 @@ static inline int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 ir > int level, bool line_status) { return -ENODEV; } > static inline void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu) { } > static inline void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu) { } > -static inline void kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) { } > +static inline bool kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) { return true; } > > static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu) > { return 0; } > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 5df359053147..a0b674d3a2da 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -4073,10 +4073,16 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, > !(vcpu->arch.shregs.msr & MSR_PR)) { > unsigned long req = kvmppc_get_gpr(vcpu, 3); > > - /* H_CEDE has to be handled now, not later */ > + /* H_CEDE has to be handled now */ > if (req == H_CEDE) { > kvmppc_cede(vcpu); > - kvmppc_xive_rearm_escalation(vcpu); /* may un-cede */ > + if (!kvmppc_xive_rearm_escalation(vcpu)) { > + /* > + * Pending escalation so abort > + * the cede. > + */ > + vcpu->arch.ceded = 0; This was moved after the mb() in kvmppc_xive_rearm_escalation, so I think a concurrent H_PROD might continue to see tvcpu->arch.ceded = 1 after the escalation has been set. Is this an issue? > + } > kvmppc_set_gpr(vcpu, 3, 0); > trap = 0; > > diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c > index e216c068075d..7b513e14cada 100644 > --- a/arch/powerpc/kvm/book3s_xive.c > +++ b/arch/powerpc/kvm/book3s_xive.c > @@ -179,12 +179,13 @@ void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu) > } > EXPORT_SYMBOL_GPL(kvmppc_xive_pull_vcpu); > > -void kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) > +bool kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) > { > void __iomem *esc_vaddr = (void __iomem *)vcpu->arch.xive_esc_vaddr; > + bool ret = true; > > if (!esc_vaddr) > - return; > + return ret; > > /* we are using XIVE with single escalation */ > > @@ -197,7 +198,7 @@ void kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) > * we also don't want to set xive_esc_on to 1 here in > * case we race with xive_esc_irq(). > */ > - vcpu->arch.ceded = 0; > + ret = false; > /* > * The escalation interrupts are special as we don't EOI them. > * There is no need to use the load-after-store ordering offset > @@ -210,6 +211,8 @@ void kvmppc_xive_rearm_escalation(struct kvm_vcpu *vcpu) > __raw_readq(esc_vaddr + XIVE_ESB_SET_PQ_00); > } > mb(); > + > + return ret; > } > EXPORT_SYMBOL_GPL(kvmppc_xive_rearm_escalation);