[PATCH 12/22] powerpc/eeh: Emulate RTAS call ibm,set-slot-reset

[Gavin Shan]

The RTAS call "ibm,set-slot-reset" is being used to reset one
particular PE, either foundamental or hot reset. The patche intends
to implement the backend to emulate the RTAS call.

Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/eeh-rtas.c | 92 +++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/eeh-rtas.c b/arch/powerpc/platforms/powernv/eeh-rtas.c
index 1a037fd..3e38d13 100644
--- a/arch/powerpc/platforms/powernv/eeh-rtas.c
+++ b/arch/powerpc/platforms/powernv/eeh-rtas.c
@@ -171,6 +171,95 @@ out:
 	return ret;
 }
 
+static int kvmppc_eeh_set_reset(struct kvm_vcpu *vcpu,
+				struct rtas_args *args)
+{
+	struct pci_controller *hose;
+	struct pnv_phb *phb;
+	struct eeh_dev *edev;
+	struct eeh_pe *pe;
+	struct eeh_vfio_pci_addr addr;
+	int opcode;
+	int ret = 0;
+
+	/* Sanity check on parameter */
+	if (args->nargs != 4 || args->nret != 1) {
+		pr_warn("%s: Non-matched arguments (%d, %d) - (4, 1)\n",
+			__func__, args->nargs, args->nret);
+		ret = -3;
+		goto out;
+	}
+
+	/* Sanity check on opcode */
+	opcode = args->args[3];
+	if (opcode != EEH_RESET_DEACTIVATE &&
+	    opcode != EEH_RESET_HOT &&
+	    opcode != EEH_RESET_FUNDAMENTAL) {
+		pr_warn("%s: Unsupported opcode %d\n",
+			__func__, opcode);
+		ret = -3;
+		goto out;
+	}
+
+	/* Figure out the address. We always have PE address */
+	if (kvmppc_eeh_format_addr(vcpu, args, &addr, false, &edev, &pe)) {
+		ret = -3;
+		goto out;
+	}
+
+	/* Insure that the EEH stuff has been initialized */
+	hose = pe->phb;
+	phb = hose->private_data;
+	if (!(phb->flags & PNV_PHB_FLAG_EEH)) {
+		pr_warn("%s: EEH disable on PHB#%d\n",
+			__func__, hose->global_number);
+		ret = -7;
+		goto out;
+	}
+
+	/* Call into the IODA dependent backend to do the reset */
+	if (!phb->eeh_ops ||
+	    !phb->eeh_ops->set_option ||
+	    !phb->eeh_ops->reset) {
+		pr_warn("%s: Unsupported request\n", __func__);
+		ret = -7;
+	} else {
+		/*
+		 * The frozen PE might be caused by the mechanism called
+		 * PAPR error injection, which is supposed to be one-shot
+		 * without "sticky" bit as being stated by the spec. But
+		 * the reality isn't that, at least on P7IOC. So we have
+		 * to clear that to avoid recrusive error, which fail the
+		 * recovery.
+		 */
+		if (opcode == EEH_RESET_DEACTIVATE)
+			opal_pci_reset(phb->opal_id,
+				       OPAL_PHB_ERROR,
+				       OPAL_ASSERT_RESET);
+
+		if (phb->eeh_ops->reset(pe, opcode)) {
+			pr_warn("%s: Failure from backend\n",
+				__func__);
+			ret = -1;
+			goto out;
+		}
+
+		/*
+		 * The PE is still in frozen state and we need clear that.
+		 * It's good to clear frozen state after deassert to avoid
+		 * messy IO access during reset, which might cause recrusive
+		 * frozen PE.
+		 */
+		if (opcode == EEH_RESET_DEACTIVATE) {
+			phb->eeh_ops->set_option(pe, EEH_OPT_THAW_MMIO);
+			phb->eeh_ops->set_option(pe, EEH_OPT_THAW_DMA);
+		}
+	}
+
+out:
+	return ret;
+}
+
 /**
  * kvmppc_eeh_rtas - Backend for EEH RTAS emulation
  * @vcpu: KVM virtual CPU
@@ -190,6 +279,9 @@ void kvmppc_eeh_rtas(struct kvm_vcpu *vcpu, struct rtas_args *args, int op)
 	case eeh_rtas_set_option:
 		ret = kvmppc_eeh_set_option(vcpu, args);
 		break;
+	case eeh_rtas_set_slot_reset:
+		ret = kvmppc_eeh_set_reset(vcpu, args);
+		break;
 	default:
 		pr_warn("%s: Unsupported EEH RTAS service#%d\n",
 			__func__, op);
-- 
1.8.3.2