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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Zhenyu Wang <zhenyuw@linux.intel.com>,
        Xiong Zhang <xiong.y.zhang@intel.com>,
        Hang Yuan <hang.yuan@linux.intel.com>,
        Stuart Summers <stuart.summers@intel.com>,
        Fred Gao <fred.gao@intel.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.9 115/255] vfio/pci: Bypass IGD init in case of -ENODEV
Date:   Tue, 17 Nov 2020 14:04:15 +0100
Message-Id: <20201117122144.543757070@linuxfoundation.org>
In-Reply-To: <20201117122138.925150709@linuxfoundation.org>
References: <20201117122138.925150709@linuxfoundation.org>
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From: Fred Gao <fred.gao@intel.com>

[ Upstream commit e4eccb853664de7bcf9518fb658f35e748bf1f68 ]

Bypass the IGD initialization when -ENODEV returns,
that should be the case if opregion is not available for IGD
or within discrete graphics device's option ROM,
or host/lpc bridge is not found.

Then use of -ENODEV here means no special device resources found
which needs special care for VFIO, but we still allow other normal
device resource access.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Xiong Zhang <xiong.y.zhang@intel.com>
Cc: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Fred Gao <fred.gao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vfio/pci/vfio_pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 1ab1f5cda4ac2..bfdc010a6b043 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -385,7 +385,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 	    pdev->vendor == PCI_VENDOR_ID_INTEL &&
 	    IS_ENABLED(CONFIG_VFIO_PCI_IGD)) {
 		ret = vfio_pci_igd_init(vdev);
-		if (ret) {
+		if (ret && ret != -ENODEV) {
 			pci_warn(pdev, "Failed to setup Intel IGD regions\n");
 			goto disable_exit;
 		}
-- 
2.27.0