linux-kernel - [PATCH] vfio/type1: Initialize resv_msi

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Message-Id: <20191015151650.30788-1-joro@8bytes.org>
Date:   Tue, 15 Oct 2019 17:16:50 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Alex Williamson <alex.williamson@...hat.com>
Cc:     Cornelia Huck <cohuck@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH] vfio/type1: Initialize resv_msi_base

From: Joerg Roedel <jroedel@...e.de>

After enabling CONFIG_IOMMU_DMA on X86 a new warning appears when
compiling vfio:

drivers/vfio/vfio_iommu_type1.c: In function ‘vfio_iommu_type1_attach_group’:
drivers/vfio/vfio_iommu_type1.c:1827:7: warning: ‘resv_msi_base’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
   ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The warning is a false positive, because the call to iommu_get_msi_cookie()
only happens when vfio_iommu_has_sw_msi() returned true. And that only
happens when it also set resv_msi_base.

But initialize the variable anyway to get rid of the warning.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 96fddc1dafc3..d864277ea16f 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1658,7 +1658,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	struct bus_type *bus = NULL;
 	int ret;
 	bool resv_msi, msi_remap;
-	phys_addr_t resv_msi_base;
+	phys_addr_t resv_msi_base = 0;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
 	LIST_HEAD(group_resv_regions);
-- 
2.16.4