[xen master] x86/iommu: snoop control is allowed only by Intel VT-d

[patchbot@xxxxxxx]

commit 80b83a3c94e55a23f647dd3c92b522d77959bdc0
Author:     Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
AuthorDate: Mon Feb 13 16:26:43 2023 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Feb 13 16:26:43 2023 +0100

    x86/iommu: snoop control is allowed only by Intel VT-d
    
    The AMD-Vi driver forces coherent accesses by hardwiring the FC bit to 1.
    Therefore, given that iommu_snoop is used only when the iommu is enabled,
    when Xen is configured with only the AMD iommu enabled, iommu_snoop can be
    reduced to a #define to true.
    
    No functional change intended.
    
    Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/include/xen/iommu.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 4f22fc1bed..626731941b 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -74,7 +74,12 @@ extern enum __packed iommu_intremap {
    iommu_intremap_restricted,
    iommu_intremap_full,
 } iommu_intremap;
-extern bool iommu_igfx, iommu_qinval, iommu_snoop;
+extern bool iommu_igfx, iommu_qinval;
+#ifdef CONFIG_INTEL_IOMMU
+extern bool iommu_snoop;
+#else
+# define iommu_snoop true
+#endif /* CONFIG_INTEL_IOMMU */
 #else
 # define iommu_intremap false
 # define iommu_snoop false
--
generated by git-patchbot for /home/xen/git/xen.git#master