From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp06.au.ibm.com ([202.81.31.148]:35436 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758174AbaEMBff (ORCPT ); Mon, 12 May 2014 21:35:35 -0400 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 13 May 2014 11:35:34 +1000 From: Gavin Shan To: kvm@vger.kernel.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, linux-pci@vger.kernel.org, Gavin Shan Subject: [PATCH 3/4] drivers/vfio/pci: Fix wrong MSI interrupt count Date: Tue, 13 May 2014 11:35:23 +1000 Message-Id: <1399944924-1200-4-git-send-email-gwshan@linux.vnet.ibm.com> In-Reply-To: <1399944924-1200-1-git-send-email-gwshan@linux.vnet.ibm.com> References: <1399944924-1200-1-git-send-email-gwshan@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: According PCI local bus specification, the register of Message Control for MSI (offset: 2, length: 2) has bit#0 to enable or disable MSI logic and it shouldn't be part contributing to the calculation of MSI interrupt count. The patch fixes the issue. Signed-off-by: Gavin Shan --- drivers/vfio/pci/vfio_pci.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 7ba0424..6b8cd07 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -196,8 +196,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type) if (pos) { pci_read_config_word(vdev->pdev, pos + PCI_MSI_FLAGS, &flags); - - return 1 << (flags & PCI_MSI_FLAGS_QMASK); + return 1 << ((flags & PCI_MSI_FLAGS_QMASK) >> 1); } } else if (irq_type == VFIO_PCI_MSIX_IRQ_INDEX) { u8 pos; -- 1.8.3.2