On Fri, Aug 18, 2023 at 05:50:04AM -0400, Xiaoyao Li wrote:
> 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>
> Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> ---
> 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 d51067fdc12a..4a146bc42f63 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -859,6 +859,15 @@ 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 33d015a08c34..a72badfbfd65 100644
> --- a/target/i386/kvm/tdx.c
> +++ b/target/i386/kvm/tdx.c
> @@ -32,6 +32,9 @@
> (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)
> @@ -513,6 +516,27 @@ int tdx_pre_create_vcpu(CPUState *cpu)
> goto out_free;
> }
>
> + 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;
> + }
error_setg(errp, ....) in all of these cases.
With regards,
Daniel
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