Reuse "-cpu,tsc-frequency=" to get user wanted tsc frequency and call VM
scope VM_SET_TSC_KHZ to set the tsc frequency of TD before KVM_TDX_INIT_VM.
Besides, sanity check the tsc frequency to be in the legal range and
legal granularity (required by TDX module).
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
Changes from RFC v4:
- Use VM scope VM_SET_TSC_KHZ to set the TSC frequency of TD since KVM
side drop the @tsc_khz field in struct kvm_tdx_init_vm
---
target/i386/kvm/kvm.c | 9 +++++++++
target/i386/kvm/tdx.c | 24 ++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 4f491f871f3e..1545b6f870f5 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -812,6 +812,15 @@ static int kvm_arch_set_tsc_khz(CPUState *cs)
int r, cur_freq;
bool set_ioctl = false;
+ /*
+ * TSC of TD vcpu is immutable, it cannot be set/changed via vcpu scope
+ * VM_SET_TSC_KHZ, but only be initialized via VM scope VM_SET_TSC_KHZ
+ * before ioctl KVM_TDX_INIT_VM in tdx_pre_create_vcpu()
+ */
+ if (is_tdx_vm()) {
+ return 0;
+ }
+
if (!env->tsc_khz) {
return 0;
}
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 42cef484c574..0162d7cc9df4 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -30,6 +30,9 @@
(1U << KVM_FEATURE_PV_SCHED_YIELD) | \
(1U << KVM_FEATURE_MSI_EXT_DEST_ID))
+#define TDX_MIN_TSC_FREQUENCY_KHZ (100 * 1000)
+#define TDX_MAX_TSC_FREQUENCY_KHZ (10 * 1000 * 1000)
+
#define TDX_TD_ATTRIBUTES_DEBUG BIT_ULL(0)
#define TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE BIT_ULL(28)
#define TDX_TD_ATTRIBUTES_PKS BIT_ULL(30)
@@ -504,6 +507,27 @@ int tdx_pre_create_vcpu(CPUState *cpu)
goto out;
}
+ r = -EINVAL;
+ if (env->tsc_khz && (env->tsc_khz < TDX_MIN_TSC_FREQUENCY_KHZ ||
+ env->tsc_khz > TDX_MAX_TSC_FREQUENCY_KHZ)) {
+ error_report("Invalid TSC %ld KHz, must specify cpu_frequency between [%d, %d] kHz",
+ env->tsc_khz, TDX_MIN_TSC_FREQUENCY_KHZ,
+ TDX_MAX_TSC_FREQUENCY_KHZ);
+ goto out;
+ }
+
+ if (env->tsc_khz % (25 * 1000)) {
+ error_report("Invalid TSC %ld KHz, it must be multiple of 25MHz", env->tsc_khz);
+ goto out;
+ }
+
+ /* it's safe even env->tsc_khz is 0. KVM uses host's tsc_khz in this case */
+ r = kvm_vm_ioctl(kvm_state, KVM_SET_TSC_KHZ, env->tsc_khz);
+ if (r < 0) {
+ error_report("Unable to set TSC frequency to %" PRId64 " kHz", env->tsc_khz);
+ goto out;
+ }
+
r = setup_td_guest_attributes(x86cpu);
if (r) {
goto out;
--
2.27.0
