[PATCH v5 18/65] i386/tdx: Make Intel-PT unsupported for TD guest

[Xiaoyao Li]

Due to the fact that Intel-PT virtualization support has been broken in
QEMU since Sapphire Rapids generation[1], below warning is triggered when
luanching TD guest:

  warning: host doesn't support requested feature: CPUID.07H:EBX.intel-pt [bit 
25]

Before Intel-pt is fixed in QEMU, just make Intel-PT unsupported for TD
guest, to avoid the confusing warning.

[1] 
https://lore.kernel.org/qemu-devel/20230531084311.3807277-1-xiaoyao.li@intel.com/

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
Changes in v4:
 - newly added patch;
---
 target/i386/kvm/tdx.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 85d96140b450..239170142e4f 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -292,6 +292,11 @@ void tdx_get_supported_cpuid(uint32_t function, uint32_t 
index, int reg,
     if (function == 1 && reg == R_ECX && !enable_cpu_pm) {
         *ret &= ~CPUID_EXT_MONITOR;
     }
+
+    /* QEMU Intel-pt support is broken, don't advertise Intel-PT */
+    if (function == 7 && reg == R_EBX) {
+        *ret &= ~CPUID_7_0_EBX_INTEL_PT;
+    }
 }
 
 enum tdx_ioctl_level{
-- 
2.34.1