From 17d48610ae0fa218aa386b16a538c792991a3652 Mon Sep 17 00:00:00 2001 From: Li Zhong Date: Fri, 11 Nov 2016 12:57:35 +0800 Subject: KVM: PPC: Book 3S: XICS: Implement ICS P/Q states This patch implements P(Presented)/Q(Queued) states for ICS irqs. When the interrupt is presented, set P. Present if P was not set. If P is already set, don't present again, set Q. When the interrupt is EOI'ed, move Q into P (and clear Q). If it is set, re-present. The asserted flag used by LSI is also incorporated into the P bit. When the irq state is saved, P/Q bits are also saved, they need some qemu modifications to be recognized and passed around to be restored. KVM_XICS_PENDING bit set and saved should also indicate KVM_XICS_PRESENTED bit set and saved. But it is possible some old code doesn't have/recognize the P bit, so when we restore, we set P for PENDING bit, too. The idea and much of the code come from Ben. Signed-off-by: Li Zhong Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_hv_rm_xics.c | 100 ++++++++++++++++++++++++----------- 1 file changed, 70 insertions(+), 30 deletions(-) (limited to 'arch/powerpc/kvm/book3s_hv_rm_xics.c') diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c index 16349c9e86ba..30f82c79de5d 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_xics.c +++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c @@ -672,51 +672,39 @@ int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr) return check_too_hard(xics, icp); } -int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr) +static int ics_rm_eoi(struct kvm_vcpu *vcpu, u32 irq) { struct kvmppc_xics *xics = vcpu->kvm->arch.xics; struct kvmppc_icp *icp = vcpu->arch.icp; struct kvmppc_ics *ics; struct ics_irq_state *state; - u32 irq = xirr & 0x00ffffff; u16 src; - - if (!xics || !xics->real_mode) - return H_TOO_HARD; + u32 pq_old, pq_new; /* - * ICP State: EOI - * - * Note: If EOI is incorrectly used by SW to lower the CPPR - * value (ie more favored), we do not check for rejection of - * a pending interrupt, this is a SW error and PAPR sepcifies - * that we don't have to deal with it. + * ICS EOI handling: For LSI, if P bit is still set, we need to + * resend it. * - * The sending of an EOI to the ICS is handled after the - * CPPR update - * - * ICP State: Down_CPPR which we handle - * in a separate function as it's shared with H_CPPR. + * For MSI, we move Q bit into P (and clear Q). If it is set, + * resend it. */ - icp_rm_down_cppr(xics, icp, xirr >> 24); - /* IPIs have no EOI */ - if (irq == XICS_IPI) - goto bail; - /* - * EOI handling: If the interrupt is still asserted, we need to - * resend it. We can take a lockless "peek" at the ICS state here. - * - * "Message" interrupts will never have "asserted" set - */ ics = kvmppc_xics_find_ics(xics, irq, &src); if (!ics) goto bail; + state = &ics->irq_state[src]; - /* Still asserted, resend it */ - if (state->asserted) - icp_rm_deliver_irq(xics, icp, irq); + if (state->lsi) + pq_new = state->pq_state; + else + do { + pq_old = state->pq_state; + pq_new = pq_old >> 1; + } while (cmpxchg(&state->pq_state, pq_old, pq_new) != pq_old); + + if (pq_new & PQ_PRESENTED) + icp_rm_deliver_irq(xics, NULL, irq); if (!hlist_empty(&vcpu->kvm->irq_ack_notifier_list)) { icp->rm_action |= XICS_RM_NOTIFY_EOI; @@ -737,10 +725,43 @@ int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr) state->intr_cpu = -1; } } + bail: return check_too_hard(xics, icp); } +int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr) +{ + struct kvmppc_xics *xics = vcpu->kvm->arch.xics; + struct kvmppc_icp *icp = vcpu->arch.icp; + u32 irq = xirr & 0x00ffffff; + + if (!xics || !xics->real_mode) + return H_TOO_HARD; + + /* + * ICP State: EOI + * + * Note: If EOI is incorrectly used by SW to lower the CPPR + * value (ie more favored), we do not check for rejection of + * a pending interrupt, this is a SW error and PAPR specifies + * that we don't have to deal with it. + * + * The sending of an EOI to the ICS is handled after the + * CPPR update + * + * ICP State: Down_CPPR which we handle + * in a separate function as it's shared with H_CPPR. + */ + icp_rm_down_cppr(xics, icp, xirr >> 24); + + /* IPIs have no EOI */ + if (irq == XICS_IPI) + return check_too_hard(xics, icp); + + return ics_rm_eoi(vcpu, irq); +} + unsigned long eoi_rc; static void icp_eoi(struct irq_chip *c, u32 hwirq, __be32 xirr, bool *again) @@ -827,14 +848,33 @@ long kvmppc_deliver_irq_passthru(struct kvm_vcpu *vcpu, { struct kvmppc_xics *xics; struct kvmppc_icp *icp; + struct kvmppc_ics *ics; + struct ics_irq_state *state; u32 irq; + u16 src; + u32 pq_old, pq_new; irq = irq_map->v_hwirq; xics = vcpu->kvm->arch.xics; icp = vcpu->arch.icp; kvmppc_rm_handle_irq_desc(irq_map->desc); - icp_rm_deliver_irq(xics, icp, irq); + + ics = kvmppc_xics_find_ics(xics, irq, &src); + if (!ics) + return 2; + + state = &ics->irq_state[src]; + + /* only MSIs register bypass producers, so it must be MSI here */ + do { + pq_old = state->pq_state; + pq_new = ((pq_old << 1) & 3) | PQ_PRESENTED; + } while (cmpxchg(&state->pq_state, pq_old, pq_new) != pq_old); + + /* Test P=1, Q=0, this is the only case where we present */ + if (pq_new == PQ_PRESENTED) + icp_rm_deliver_irq(xics, icp, irq); /* EOI the interrupt */ icp_eoi(irq_desc_get_chip(irq_map->desc), irq_map->r_hwirq, xirr, -- cgit