On 11/5/2024 5:55 PM, Paolo Bonzini wrote:
On 11/5/24 07:23, Xiaoyao Li wrote:
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
This should be unnecessary now that QEMU has
kvm_mark_guest_state_protected().
Reverting this patch, we get:
tdx: tdx: error: failed to set MSR 0x174 to 0x0
tdx: ../../../go/src/tdx/tdx-qemu/target/i386/kvm/kvm.c:3859:
kvm_buf_set_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.
error: failed to set MSR 0x174 to 0x0
tdx: ../../../go/src/tdx/tdx-qemu/target/i386/kvm/kvm.c:3859:
kvm_buf_set_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.
Paolo
---
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 c39e879a77e9..e47aa32233e6 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -5254,6 +5254,11 @@ int kvm_arch_put_registers(CPUState *cpu, int
level, Error **errp)
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
@@ -5368,6 +5373,12 @@ int kvm_arch_get_registers(CPUState *cs, Error
**errp)
error_setg_errno(errp, -ret, "Failed to get MP state");
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) {
error_setg_errno(errp, -ret, "Failed to get general purpose
registers");
