Re: [PATCH 3/6] KVM: PPC: Book3S HV P9: Move cede logic out of XIVE escalation rearming
From: Cédric Le Goater <clg@kaod.org>
Date: 2022-03-09 15:12:50
On 3/3/22 06:33, Nicholas Piggin wrote:
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 <npiggin@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> In xive_esc_irq() : if (vcpu->arch.ceded) kvmppc_fast_vcpu_kick(vcpu); which does : vcpu->kvm->arch.kvm_ops->fast_vcpu_kick(vcpu); That's a lot of indirection which are costly on PPC. May be for this case, since we know XIVE is only supported on KVM HV, we could use directly kvmppc_fast_vcpu_kick_hv(). Thanks, C.
quoted hunk ↗ jump to hunk
--- 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; + } 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);