[Xen-devel] [PATCH 3/5] x86/hvm: Make HVM_PARAM_{STORE, CONSOLE}_EVTCHN read-only to the guest

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

These values are set by the toolstack for each create/restore operation, and
bound by xen{store,console}d before the the guest starts running.

A guest has no reason to modify them at all, and the matching *_PFN parameters
are already read-only.  Adjust the *_EVTCHN permissions to be consistent.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Paul Durrant <paul.durrant@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/x86/hvm/hvm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index d19ae35..408e695 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4079,8 +4079,6 @@ static int hvm_allow_set_param(struct domain *d,
     case HVM_PARAM_VM86_TSS_SIZED:
     case HVM_PARAM_ACPI_IOPORTS_LOCATION:
     case HVM_PARAM_VM_GENERATION_ID_ADDR:
-    case HVM_PARAM_STORE_EVTCHN:
-    case HVM_PARAM_CONSOLE_EVTCHN:
     case HVM_PARAM_X87_FIP_WIDTH:
         break;
 
@@ -4090,6 +4088,7 @@ static int hvm_allow_set_param(struct domain *d,
          * permissions in Xen, and therefore may not set by the domain.
          */
     case HVM_PARAM_STORE_PFN:
+    case HVM_PARAM_STORE_EVTCHN:
     case HVM_PARAM_PAE_ENABLED:
     case HVM_PARAM_IOREQ_PFN:
     case HVM_PARAM_BUFIOREQ_PFN:
@@ -4101,6 +4100,7 @@ static int hvm_allow_set_param(struct domain *d,
     case HVM_PARAM_ACPI_S_STATE:
     case HVM_PARAM_VPT_ALIGN:
     case HVM_PARAM_CONSOLE_PFN:
+    case HVM_PARAM_CONSOLE_EVTCHN:
     case HVM_PARAM_NESTEDHVM:
     case HVM_PARAM_PAGING_RING_PFN:
     case HVM_PARAM_MONITOR_RING_PFN:
-- 
2.1.4


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