From 688124cc541f60d26a7547f45637b23dada4e527 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 19 Mar 2025 10:21:00 +0800 Subject: [PATCH] iommu/vt-d: Don't clobber posted vCPU IRTE when host IRQ affinity changes Don't overwrite an IRTE that is posting IRQs to a vCPU with a posted MSI entry if the host IRQ affinity happens to change. If/when the IRTE is reverted back to "host mode", it will be reconfigured as a posted MSI or remapped entry as appropriate. Drop the "mode" field, which doesn't differentiate between posted MSIs and posted vCPUs, in favor of a dedicated posted_vcpu flag. Note! The two posted_{msi,vcpu} flags are intentionally not mutually exclusive; an IRTE can transition between posted MSI and posted vCPU. Fixes: ed1e48ea4370 ("iommu/vt-d: Enable posted mode for device MSIs") Cc: stable@vger.kernel.org Cc: Thomas Gleixner Cc: Jacob Pan Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20250315025135.2365846-3-seanjc@google.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel/irq_remapping.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c index c495b533103f..ea3ca5203919 100644 --- a/drivers/iommu/intel/irq_remapping.c +++ b/drivers/iommu/intel/irq_remapping.c @@ -25,11 +25,6 @@ #include "../irq_remapping.h" #include "../iommu-pages.h" -enum irq_mode { - IRQ_REMAPPING, - IRQ_POSTING, -}; - struct ioapic_scope { struct intel_iommu *iommu; unsigned int id; @@ -49,8 +44,8 @@ struct irq_2_iommu { u16 irte_index; u16 sub_handle; u8 irte_mask; - enum irq_mode mode; bool posted_msi; + bool posted_vcpu; }; struct intel_ir_data { @@ -138,7 +133,6 @@ static int alloc_irte(struct intel_iommu *iommu, irq_iommu->irte_index = index; irq_iommu->sub_handle = 0; irq_iommu->irte_mask = mask; - irq_iommu->mode = IRQ_REMAPPING; } raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags); @@ -193,8 +187,6 @@ static int modify_irte(struct irq_2_iommu *irq_iommu, rc = qi_flush_iec(iommu, index, 0); - /* Update iommu mode according to the IRTE mode */ - irq_iommu->mode = irte->pst ? IRQ_POSTING : IRQ_REMAPPING; raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags); return rc; @@ -1173,9 +1165,18 @@ static void __intel_ir_reconfigure_irte(struct irq_data *irqd, bool force_host) { struct intel_ir_data *ir_data = irqd->chip_data; + /* + * Don't modify IRTEs for IRQs that are being posted to vCPUs if the + * host CPU affinity changes. + */ + if (ir_data->irq_2_iommu.posted_vcpu && !force_host) + return; + + ir_data->irq_2_iommu.posted_vcpu = false; + 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) + else modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry); } @@ -1270,6 +1271,7 @@ static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *info) irte_pi.pda_h = (vcpu_pi_info->pi_desc_addr >> 32) & ~(-1UL << PDA_HIGH_BIT); + ir_data->irq_2_iommu.posted_vcpu = true; modify_irte(&ir_data->irq_2_iommu, &irte_pi); } @@ -1496,6 +1498,9 @@ static void intel_irq_remapping_deactivate(struct irq_domain *domain, struct intel_ir_data *data = irq_data->chip_data; struct irte entry; + WARN_ON_ONCE(data->irq_2_iommu.posted_vcpu); + data->irq_2_iommu.posted_vcpu = false; + memset(&entry, 0, sizeof(entry)); modify_irte(&data->irq_2_iommu, &entry); }