diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_xive_template.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_xive_template.c | 68 |
1 files changed, 65 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_xive_template.c b/arch/powerpc/kvm/book3s_xive_template.c index 4636ca6e7d38..d1ed2c41b5d2 100644 --- a/arch/powerpc/kvm/book3s_xive_template.c +++ b/arch/powerpc/kvm/book3s_xive_template.c @@ -16,7 +16,22 @@ static void GLUE(X_PFX,ack_pending)(struct kvmppc_xive_vcpu *xc) u8 cppr; u16 ack; - /* XXX DD1 bug workaround: Check PIPR vs. CPPR first ! */ + /* + * Ensure any previous store to CPPR is ordered vs. + * the subsequent loads from PIPR or ACK. + */ + eieio(); + + /* + * DD1 bug workaround: If PIPR is less favored than CPPR + * ignore the interrupt or we might incorrectly lose an IPB + * bit. + */ + if (cpu_has_feature(CPU_FTR_POWER9_DD1)) { + u8 pipr = __x_readb(__x_tima + TM_QW1_OS + TM_PIPR); + if (pipr >= xc->hw_cppr) + return; + } /* Perform the acknowledge OS to register cycle. */ ack = be16_to_cpu(__x_readw(__x_tima + TM_SPC_ACK_OS_REG)); @@ -235,6 +250,11 @@ skip_ipi: /* * If we found an interrupt, adjust what the guest CPPR should * be as if we had just fetched that interrupt from HW. + * + * Note: This can only make xc->cppr smaller as the previous + * loop will only exit with hirq != 0 if prio is lower than + * the current xc->cppr. Thus we don't need to re-check xc->mfrr + * for pending IPIs. */ if (hirq) xc->cppr = prio; @@ -381,6 +401,12 @@ X_STATIC int GLUE(X_PFX,h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr) xc->cppr = cppr; /* + * Order the above update of xc->cppr with the subsequent + * read of xc->mfrr inside push_pending_to_hw() + */ + smp_mb(); + + /* * We are masking less, we need to look for pending things * to deliver and set VP pending bits accordingly to trigger * a new interrupt otherwise we might miss MFRR changes for @@ -420,21 +446,37 @@ X_STATIC int GLUE(X_PFX,h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr) * used to signal MFRR changes is EOId when fetched from * the queue. */ - if (irq == XICS_IPI || irq == 0) + if (irq == XICS_IPI || irq == 0) { + /* + * This barrier orders the setting of xc->cppr vs. + * subsquent test of xc->mfrr done inside + * scan_interrupts and push_pending_to_hw + */ + smp_mb(); goto bail; + } /* Find interrupt source */ sb = kvmppc_xive_find_source(xive, irq, &src); if (!sb) { pr_devel(" source not found !\n"); rc = H_PARAMETER; + /* Same as above */ + smp_mb(); goto bail; } state = &sb->irq_state[src]; kvmppc_xive_select_irq(state, &hw_num, &xd); state->in_eoi = true; - mb(); + + /* + * This barrier orders both setting of in_eoi above vs, + * subsequent test of guest_priority, and the setting + * of xc->cppr vs. subsquent test of xc->mfrr done inside + * scan_interrupts and push_pending_to_hw + */ + smp_mb(); again: if (state->guest_priority == MASKED) { @@ -461,6 +503,14 @@ again: } + /* + * This barrier orders the above guest_priority check + * and spin_lock/unlock with clearing in_eoi below. + * + * It also has to be a full mb() as it must ensure + * the MMIOs done in source_eoi() are completed before + * state->in_eoi is visible. + */ mb(); state->in_eoi = false; bail: @@ -495,6 +545,18 @@ X_STATIC int GLUE(X_PFX,h_ipi)(struct kvm_vcpu *vcpu, unsigned long server, /* Locklessly write over MFRR */ xc->mfrr = mfrr; + /* + * The load of xc->cppr below and the subsequent MMIO store + * to the IPI must happen after the above mfrr update is + * globally visible so that: + * + * - Synchronize with another CPU doing an H_EOI or a H_CPPR + * updating xc->cppr then reading xc->mfrr. + * + * - The target of the IPI sees the xc->mfrr update + */ + mb(); + /* Shoot the IPI if most favored than target cppr */ if (mfrr < xc->cppr) __x_writeq(0, __x_trig_page(&xc->vp_ipi_data)); |