From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: [PATCH] iommu/vt-d: Don't store SIRTP request Date: Mon, 11 Aug 2014 13:13:25 +0200 Message-ID: <53E8A555.5010905@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Joerg Roedel , iommu , Linux Kernel Mailing List Cc: Jiang Liu List-Id: iommu@lists.linux-foundation.org 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 --- 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); -- 1.8.1.1.298.ge7eed54