Bit 28 of TD attribute, named SEPT_VE_DISABLE. When set to 1, it disables
EPT violation conversion to #VE on guest TD access of PENDING pages.
Some guest OS (e.g., Linux TD guest) may require this bit as 1.
Otherwise refuse to boot.
Add sept-ve-disable property for tdx-guest object, for user to configure
this bit.
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Acked-by: Markus Armbruster <armbru@xxxxxxxxxx>
---
Changes in v4:
- collect Acked-by from Markus
Changes in v3:
- update the comment of property @sept-ve-disable to make it more
descriptive and use new format. (Daniel and Markus)
---
qapi/qom.json | 7 ++++++-
target/i386/kvm/tdx.c | 24 ++++++++++++++++++++++++
2 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/qapi/qom.json b/qapi/qom.json
index 5b3c3146947f..2177f3101382 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -900,10 +900,15 @@
#
# Properties for tdx-guest objects.
#
+# @sept-ve-disable: toggle bit 28 of TD attributes to control disabling
+# of EPT violation conversion to #VE on guest TD access of PENDING
+# pages. Some guest OS (e.g., Linux TD guest) may require this to
+# be set, otherwise they refuse to boot.
+#
# Since: 9.0
##
{ 'struct': 'TdxGuestProperties',
- 'data': { }}
+ 'data': { '*sept-ve-disable': 'bool' } }
##
# @ThreadContextProperties:
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 634aca504b32..51db64bec7ce 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -32,6 +32,8 @@
(1U << KVM_FEATURE_PV_SCHED_YIELD) | \
(1U << KVM_FEATURE_MSI_EXT_DEST_ID))
+#define TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE BIT_ULL(28)
+
#define TDX_ATTRIBUTES_MAX_BITS 64
static FeatureMask tdx_attrs_ctrl_fields[TDX_ATTRIBUTES_MAX_BITS] = {
@@ -513,6 +515,24 @@ int tdx_pre_create_vcpu(CPUState *cpu, Error **errp)
return 0;
}
+static bool tdx_guest_get_sept_ve_disable(Object *obj, Error **errp)
+{
+ TdxGuest *tdx = TDX_GUEST(obj);
+
+ return !!(tdx->attributes & TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE);
+}
+
+static void tdx_guest_set_sept_ve_disable(Object *obj, bool value, Error **errp)
+{
+ TdxGuest *tdx = TDX_GUEST(obj);
+
+ if (value) {
+ tdx->attributes |= TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE;
+ } else {
+ tdx->attributes &= ~TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE;
+ }
+}
+
/* tdx guest */
OBJECT_DEFINE_TYPE_WITH_INTERFACES(TdxGuest,
tdx_guest,
@@ -528,6 +548,10 @@ static void tdx_guest_init(Object *obj)
qemu_mutex_init(&tdx->lock);
tdx->attributes = 0;
+
+ object_property_add_bool(obj, "sept-ve-disable",
+ tdx_guest_get_sept_ve_disable,
+ tdx_guest_set_sept_ve_disable);
}
static void tdx_guest_finalize(Object *obj)
--
2.34.1
