[PATCH v3] s390/pci: fix CPU address in MSI for directed IRQ

From: Alexander Gordeev <agordeev@linux.ibm.com>
To: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	Halil Pasic <pasic@linux.ibm.com>
Subject: [PATCH v3] s390/pci: fix CPU address in MSI for directed IRQ
Date: Thu, 26 Nov 2020 18:00:37 +0100	[thread overview]
Message-ID: <1606410037-11436-1-git-send-email-agordeev@linux.ibm.com> (raw)

The directed MSIs are delivered to CPUs whose address is
written to the MSI message data. The current code assumes
that a CPU logical number (as it is seen by the kernel)
is also that CPU address.

The above assumption is not correct, as the CPU address
is rather the value returned by STAP instruction. That
value does not necessarily match the kernel logical CPU
number.

Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
 arch/s390/pci/pci_irq.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c
index 743f257cf2cb..75217fb63d7b 100644
--- a/arch/s390/pci/pci_irq.c
+++ b/arch/s390/pci/pci_irq.c
@@ -103,9 +103,10 @@ static int zpci_set_irq_affinity(struct irq_data *data, const struct cpumask *de
 {
 	struct msi_desc *entry = irq_get_msi_desc(data->irq);
 	struct msi_msg msg = entry->msg;
+	int cpu_addr = smp_cpu_get_cpu_address(cpumask_first(dest));
 
 	msg.address_lo &= 0xff0000ff;
-	msg.address_lo |= (cpumask_first(dest) << 8);
+	msg.address_lo |= (cpu_addr << 8);
 	pci_write_msi_msg(data->irq, &msg);
 
 	return IRQ_SET_MASK_OK;
@@ -238,6 +239,7 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 	unsigned long bit;
 	struct msi_desc *msi;
 	struct msi_msg msg;
+	int cpu_addr;
 	int rc, irq;
 
 	zdev->aisb = -1UL;
@@ -287,9 +289,15 @@ int arch_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 					 handle_percpu_irq);
 		msg.data = hwirq - bit;
 		if (irq_delivery == DIRECTED) {
+			if (msi->affinity)
+				cpu = cpumask_first(&msi->affinity->mask);
+			else
+				cpu = 0;
+			cpu_addr = smp_cpu_get_cpu_address(cpu);
+
 			msg.address_lo = zdev->msi_addr & 0xff0000ff;
-			msg.address_lo |= msi->affinity ?
-				(cpumask_first(&msi->affinity->mask) << 8) : 0;
+			msg.address_lo |= (cpu_addr << 8);
+
 			for_each_possible_cpu(cpu) {
 				airq_iv_set_data(zpci_ibv[cpu], hwirq, irq);
 			}
-- 
2.26.0

