XenHypercallLib has two clients at the moment: XenBusDxe and
XenConsoleSerialPortLib. Currently, when XenBusDxe starts on a non-Xen X86
platform (ie. as part of OVMF not running on Xen), the X86XenHypercallLib
instance built into it fails to initialize, which triggers an ASSERT() in
auto-generated code.
Instead, let's call XenHypercallIsAvailable() in the driver's entry point,
and exit cleanly when the driver is started on a non-Xen platform.
Modify the constructor of XenConsoleSerialPortLib similarly; we shouldn't
proceed if Xen is not available. In practice this check should never fail,
because XenConsoleSerialPortLib is only used on ARM, and
ArmXenHypercallLib is always available; but nonetheless we should be
pedantic.
Reported-by: Gabriel L. Somlo <gso...@gmail.com>
Suggested-by: Jordan Justen <jordan.l.jus...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c | 4 ++++
OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c | 8 +++++++-
OvmfPkg/XenBusDxe/XenBusDxe.c | 5 +++++
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
index 9802235..467cb27 100644
--- a/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
+++ b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
@@ -40,6 +40,10 @@ SerialPortInitialize (
VOID
)
{
+ if (! XenHypercallIsAvailable ()) {
+ return RETURN_NOT_FOUND;
+ }
+
if (!mXenConsoleInterface) {
mXenConsoleEventChain.port = (UINT32)XenHypercallHvmGetParam
(HVM_PARAM_CONSOLE_EVTCHN);
mXenConsoleInterface = (struct xencons_interface *)(UINTN)
diff --git a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
index 67892bc..7cb7f46 100644
--- a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
+++ b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
@@ -65,7 +65,13 @@ XenHypercallLibInit (
GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
if (GuidHob == NULL) {
- return RETURN_NOT_FOUND;
+ //
+ // We don't fail library construction, since that has catastrophic
+ // consequences for client modules (whereas those modules may easily be
+ // running on a non-Xen platform). Instead, XenHypercallIsAvailable() above
+ // will return FALSE.
+ //
+ return RETURN_SUCCESS;
}
XenInfo = (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
HyperPage = XenInfo->HyperPages;
diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.c b/OvmfPkg/XenBusDxe/XenBusDxe.c
index 2c4a086..439b060 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.c
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.c
@@ -165,6 +165,7 @@ XenBusDxeUnload (
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The operation completed successfully.
+ @retval EFI_ABORTED Xen hypercalls are not available.
@retval Others An unexpected error occurred.
**/
EFI_STATUS
@@ -176,6 +177,10 @@ XenBusDxeDriverEntryPoint (
{
EFI_STATUS Status;
+ if (! XenHypercallIsAvailable ()) {
+ return EFI_ABORTED;
+ }
+
//
// Install UEFI Driver Model protocol(s).
//
--
1.8.3.1
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