From f63ef69028742b09c1c0896177d555a30ff6cf13 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 11 Aug 2014 13:13:25 +0200 Subject: [PATCH] iommu/vt-d: Don't store SIRTP request Don't store the SIRTP request bit in the register state. It will otherwise become sticky and could request an Interrupt Remap Table Pointer update on each command register write. Found while starting to emulate IR in QEMU, not by observing problems on real hardware. Signed-off-by: Jan Kiszka Signed-off-by: Joerg Roedel --- drivers/iommu/intel_irq_remapping.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 0df41f6..a872874 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -438,8 +438,7 @@ static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode) (addr) | IR_X2APIC_MODE(mode) | INTR_REMAP_TABLE_REG_SIZE); /* Set interrupt-remapping table pointer */ - iommu->gcmd |= DMA_GCMD_SIRTP; - writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG); + writel(iommu->gcmd | DMA_GCMD_SIRTP, iommu->reg + DMAR_GCMD_REG); IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl, (sts & DMA_GSTS_IRTPS), sts); -- 2.7.4