[xen stable-4.18] docs: Fix IOMMU command line docs some more

[patchbot@xxxxxxx]

commit 0bcd5b347f3d00df09b3aec4e6b6fa2c732a00eb
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Oct 31 12:02:15 2023 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Oct 31 16:00:42 2023 +0000

    docs: Fix IOMMU command line docs some more
    
    Make the command line docs match the actual implementation, and state that 
the
    default behaviour is selected at compile time.
    
    Fixes: 980d6acf1517 ("IOMMU: make DMA containment of quarantined devices 
optional")
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>
    (cherry picked from commit 850382254b78e07e7ccbf80010c3b43897a158f9)
---
 docs/misc/xen-command-line.pandoc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc 
b/docs/misc/xen-command-line.pandoc
index 6b07d0f3a1..9a19a04157 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -1480,7 +1480,8 @@ detection of systems known to misbehave upon accesses to 
that port.
 > Default: `new` unless directed-EOI is supported
 
 ### iommu
-    = List of [ <bool>, verbose, debug, force, required, 
quarantine[=scratch-page],
+    = List of [ <bool>, verbose, debug, force, required,
+                quarantine=<bool>|scratch-page,
                 sharept, superpages, intremap, intpost, crash-disable,
                 snoop, qinval, igfx, amd-iommu-perdev-intremap,
                 dom0-{passthrough,strict} ]
@@ -1519,7 +1520,8 @@ boolean (e.g. `iommu=no`) can override this and leave the 
IOMMUs disabled.
     successfully.
 
 *   The `quarantine` option can be used to control Xen's behavior when
-    de-assigning devices from guests.
+    de-assigning devices from guests.  The default behaviour is chosen at
+    compile time, and is one of 
`CONFIG_IOMMU_QUARANTINE_{NONE,BASIC,SCRATCH_PAGE}`.
 
     When a PCI device is assigned to an untrusted domain, it is possible
     for that domain to program the device to DMA to an arbitrary address.
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.18