[tip:x86/apic] iommu, x86: Properly handle posted interrupts for IOMMU hotplug

[tip-bot for Feng Wu]

Commit-ID:  c1d993341e46867af9412cf7f93f535895bbe3a7
Gitweb:     http://git.kernel.org/tip/c1d993341e46867af9412cf7f93f535895bbe3a7
Author:     Feng Wu <feng.wu@xxxxxxxxx>
AuthorDate: Tue, 9 Jun 2015 13:20:37 +0800
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 12 Jun 2015 11:33:52 +0200

iommu, x86: Properly handle posted interrupts for IOMMU hotplug

Return error when inserting a new IOMMU which doesn't support posted
interrupts if posted interrupts are already enabled.

Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Joerg Roedel <joro@xxxxxxxxxx>
Cc: jiang.liu@xxxxxxxxxxxxxxx
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: dwmw2@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1433827237-3382-11-git-send-email-feng.wu@xxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 drivers/iommu/intel_irq_remapping.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 0f57af7..80f1d14 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1355,6 +1355,9 @@ int dmar_ir_hotplug(struct dmar_drhd_unit *dmaru, bool insert)
 		return -EINVAL;
 	if (!ecap_ir_support(iommu->ecap))
 		return 0;
+	if (irq_remapping_cap(IRQ_POSTING_CAP) &&
+	    !cap_pi_support(iommu->cap))
+		return -EBUSY;
 
 	if (insert) {
 		if (!iommu->ir_table)
--
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