i386/tdx: Define supported KVM features for TDX

For TDX, only limited KVM PV features are supported.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-50-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 0f7f47c6da873725743030e550c9a8257b6c9065..e35983ad9bdeae08979ccaaf5af0745175ede649 100644 (file)
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -32,6 +32,8 @@
 #include "kvm_i386.h"
 #include "tdx.h"
 
+#include "standard-headers/asm-x86/kvm_para.h"
+
 #define TDX_MIN_TSC_FREQUENCY_KHZ   (100 * 1000)
 #define TDX_MAX_TSC_FREQUENCY_KHZ   (10 * 1000 * 1000)
 
@@ -44,6 +46,14 @@
                                  TDX_TD_ATTRIBUTES_PKS | \
                                  TDX_TD_ATTRIBUTES_PERFMON)
 
+#define TDX_SUPPORTED_KVM_FEATURES  ((1U << KVM_FEATURE_NOP_IO_DELAY) | \
+                                     (1U << KVM_FEATURE_PV_UNHALT) | \
+                                     (1U << KVM_FEATURE_PV_TLB_FLUSH) | \
+                                     (1U << KVM_FEATURE_PV_SEND_IPI) | \
+                                     (1U << KVM_FEATURE_POLL_CONTROL) | \
+                                     (1U << KVM_FEATURE_PV_SCHED_YIELD) | \
+                                     (1U << KVM_FEATURE_MSI_EXT_DEST_ID))
+
 static TdxGuest *tdx_guest;
 
 static struct kvm_tdx_capabilities *tdx_caps;
@@ -631,6 +641,14 @@ static void tdx_add_supported_cpuid_by_xfam(void)
     e->edx |= (tdx_caps->supported_xfam & CPUID_XSTATE_XSS_MASK) >> 32;
 }
 
+static void tdx_add_supported_kvm_features(void)
+{
+    struct kvm_cpuid_entry2 *e;
+
+    e = find_in_supported_entry(0x40000001, 0);
+    e->eax = TDX_SUPPORTED_KVM_FEATURES;
+}
+
 static void tdx_setup_supported_cpuid(void)
 {
     if (tdx_supported_cpuid) {
@@ -647,6 +665,8 @@ static void tdx_setup_supported_cpuid(void)
     tdx_add_supported_cpuid_by_fixed1_bits();
     tdx_add_supported_cpuid_by_attrs();
     tdx_add_supported_cpuid_by_xfam();
+
+    tdx_add_supported_kvm_features();
 }
 
 static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)