linux-kernel - [PATCH v6 10/29] iommu/vt-d: Implement minor tweaks for NMI irqs

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Message-Id: <20220506000008.30892-11-ricardo.neri-calderon@linux.intel.com>
Date:   Thu,  5 May 2022 16:59:49 -0700
From:   Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org
Cc:     Tony Luck <tony.luck@...el.com>, Andi Kleen <ak@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joerg Roedel <joro@...tes.org>,
        Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
        David Woodhouse <dwmw2@...radead.org>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Nicholas Piggin <npiggin@...il.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Ricardo Neri <ricardo.neri@...el.com>,
        iommu@...ts.linux-foundation.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Subject: [PATCH v6 10/29] iommu/vt-d: Implement minor tweaks for NMI irqs

The Intel IOMMU interrupt remapping driver already programs correctly the
delivery mode of individual irqs as per their irq_data. Improve handling
of NMIs. Allow only one irq per NMI. Also, it is not necessary to cleanup
irq vectors after updating affinity. NMIs do not have associated vectors.

Cc: Andi Kleen <ak@...ux.intel.com>
Cc: David Woodhouse <dwmw2@...radead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@...el.com>
Cc: Lu Baolu <baolu.lu@...ux.intel.com>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: iommu@...ts.linux-foundation.org
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: x86@...nel.org
Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
---
Changes since v5:
 * Introduced this patch.

Changes since v4:
 * N/A

Changes since v3:
 * N/A

Changes since v2:
 * N/A

Changes since v1:
 * N/A
---
 drivers/iommu/intel/irq_remapping.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
index fb2d71bea98d..791a9331e257 100644
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -1198,8 +1198,12 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
 	 * After this point, all the interrupts will start arriving
 	 * at the new destination. So, time to cleanup the previous
 	 * vector allocation.
+	 *
+	 * Do it only for non-NMI irqs. NMIs don't have associated
+	 * vectors.
 	 */
-	send_cleanup_vector(cfg);
+	if (cfg->delivery_mode != APIC_DELIVERY_MODE_NMI)
+		send_cleanup_vector(cfg);
 
 	return IRQ_SET_MASK_OK_DONE;
 }
@@ -1352,6 +1356,9 @@ static int intel_irq_remapping_alloc(struct irq_domain *domain,
 	if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
 		info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
 
+	if ((info->flags & X86_IRQ_ALLOC_AS_NMI) && nr_irqs != 1)
+		return -EINVAL;
+
 	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
 	if (ret < 0)
 		return ret;
-- 
2.17.1