[Xen-changelog] [xen staging] xen/arm: iommu: Panic if not all IOMMUs are initialized

[patchbot@xxxxxxx]

commit ce44fd015e55d0ecc47c160fb5ce69070aa4991b
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Tue Aug 20 13:22:55 2019 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Thu Sep 19 17:28:25 2019 -0700

    xen/arm: iommu: Panic if not all IOMMUs are initialized
    
    At the moment, the platform can come up with only part of the IOMMUs
    initialized. This could lead to a failure later on when building the
    hardware domain or even trying to assign a device to a guest.
    
    To avoid unwanted behavior, Xen will not continue if one of the IOMMUs
    has not been initialized correctly.
    
    [stefano: fix typo in comment, add '\n' to panic message]
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
 xen/arch/arm/setup.c                | 5 ++++-
 xen/drivers/passthrough/arm/iommu.c | 8 ++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 077b8d02a0..581b262655 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -784,6 +784,7 @@ void __init start_xen(unsigned long boot_phys_offset,
         .max_grant_frames = gnttab_dom0_frames(),
         .max_maptrack_frames = opt_max_maptrack_frames,
     };
+    int rc;
 
     dcache_line_bytes = read_dcache_line_bytes();
 
@@ -923,7 +924,9 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     setup_virt_paging();
 
-    iommu_setup();
+    rc = iommu_setup();
+    if ( !iommu_enabled && rc != -ENODEV )
+        panic("Couldn't configure correctly all the IOMMUs.\n");
 
     do_initcalls();
 
diff --git a/xen/drivers/passthrough/arm/iommu.c 
b/xen/drivers/passthrough/arm/iommu.c
index 9cfb589083..2678ef5c01 100644
--- a/xen/drivers/passthrough/arm/iommu.c
+++ b/xen/drivers/passthrough/arm/iommu.c
@@ -52,6 +52,14 @@ int __init iommu_hardware_setup(void)
         rc = device_init(np, DEVICE_IOMMU, NULL);
         if ( !rc )
             num_iommus++;
+        /*
+         * Ignore the following error codes:
+         *   - EBADF: Indicate the current is not an IOMMU
+         *   - ENODEV: The IOMMU is not present or cannot be used by
+         *     Xen.
+         */
+        else if ( rc != -EBADF && rc != -ENODEV )
+            return rc;
     }
 
     return ( num_iommus > 0 ) ? 0 : -ENODEV;
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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