[PATCH v3 69/70] i386/tdx: Don't get/put guest state for TDX VMs

Xiaoyao Li
2023-11-15T07:24:17Z

From: Sean Christopherson <sean.j.christopherson@intel.com>

Don't get/put state of TDX VMs since accessing/mutating guest state of
production TDs is not supported.

Note, it will be allowed for a debug TD. Corresponding support will be
introduced when debug TD support is implemented in the future.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
---
target/i386/kvm/kvm.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 5c5400c51cd1..56171dc76235 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -4621,6 +4621,11 @@ int kvm_arch_put_registers(CPUState *cpu, int level)

assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu));

+ /* TODO: Allow accessing guest state for debug TDs. */
+ if (is_tdx_vm()) {
+ return 0;
+ }
+
/*
* Put MSR_IA32_FEATURE_CONTROL first, this ensures the VM gets out of VMX
* root operation upon vCPU reset. kvm_put_msr_feature_control() should also
@@ -4721,6 +4726,12 @@ int kvm_arch_get_registers(CPUState *cs)
if (ret < 0) {
goto out;
}
+
+ /* TODO: Allow accessing guest state for debug TDs. */
+ if (is_tdx_vm()) {
+ return 0;
+ }
+
ret = kvm_getput_regs(cpu, 0);
if (ret < 0) {
goto out;
--
2.34.1