Commit 2454823e authored by Sean Christopherson's avatar Sean Christopherson Committed by Joerg Roedel
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iommu/vt-d: Put IRTE back into posted MSI mode if vCPU posting is disabled 



Add a helper to take care of reconfiguring an IRTE to deliver IRQs to the
host, i.e. not to a vCPU, and use the helper when an IRTE's vCPU affinity
is nullified, i.e. when KVM puts an IRTE back into "host" mode.  Because
posted MSIs use an ephemeral IRTE, using modify_irte() puts the IRTE into
full remapped mode, i.e. unintentionally disables posted MSIs on the IRQ.

Fixes: ed1e48ea ("iommu/vt-d: Enable posted mode for device MSIs")
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250315025135.2365846-2-seanjc@google.com


Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 4c293add

drivers/iommu/intel/irq_remapping.c

+13 −6
Original line number Diff line number Diff line
@@ -1169,7 +1169,17 @@ static void intel_ir_reconfigure_irte_posted(struct irq_data *irqd) 
static inline void intel_ir_reconfigure_irte_posted(struct irq_data *irqd) {}

#endif



static void intel_ir_reconfigure_irte(struct irq_data *irqd, bool force)

static void __intel_ir_reconfigure_irte(struct irq_data *irqd, bool force_host)

{

	struct intel_ir_data *ir_data = irqd->chip_data;



	if (ir_data->irq_2_iommu.posted_msi)

		intel_ir_reconfigure_irte_posted(irqd);

	else if (force_host || ir_data->irq_2_iommu.mode == IRQ_REMAPPING)

		modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry);

}



static void intel_ir_reconfigure_irte(struct irq_data *irqd, bool force_host)

{

	struct intel_ir_data *ir_data = irqd->chip_data;

	struct irte *irte = &ir_data->irte_entry;
@@ -1182,10 +1192,7 @@ static void intel_ir_reconfigure_irte(struct irq_data *irqd, bool force) 
	irte->vector = cfg->vector;

	irte->dest_id = IRTE_DEST(cfg->dest_apicid);



	if (ir_data->irq_2_iommu.posted_msi)

		intel_ir_reconfigure_irte_posted(irqd);

	else if (force || ir_data->irq_2_iommu.mode == IRQ_REMAPPING)

		modify_irte(&ir_data->irq_2_iommu, irte);

	__intel_ir_reconfigure_irte(irqd, force_host);

}



/*
@@ -1240,7 +1247,7 @@ static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *info) 


	/* stop posting interrupts, back to the default mode */

	if (!vcpu_pi_info) {

		modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry);

		__intel_ir_reconfigure_irte(data, true);

	} else {

		struct irte irte_pi;