On 4/16/2024 4:32 PM, Chenyi Qiang wrote:
>
>
> On 2/29/2024 2:36 PM, Xiaoyao Li wrote:
>> Current KVM doesn't support PMU for TD guest. It returns error if TD is
>> created with PMU bit being set in attributes.
>>
>> Disable PMU for TD guest on QEMU side.
>>
>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>> ---
>> target/i386/kvm/tdx.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
>> index 262e86fd2c67..1c12cda002b8 100644
>> --- a/target/i386/kvm/tdx.c
>> +++ b/target/i386/kvm/tdx.c
>> @@ -496,6 +496,8 @@ int tdx_pre_create_vcpu(CPUState *cpu, Error **errp)
>> g_autofree struct kvm_tdx_init_vm *init_vm = NULL;
>> int r = 0;
>>
>> + object_property_set_bool(OBJECT(cpu), "pmu", false, &error_abort);
>
> Is it necessary to output some prompt if the user wants to enable pmu by
> "-cpu host,pmu=on"? As in patch 27, it mentions PMU is configured by
> x86cpu->enable_pmu, but PMU is actually not support in this series and
> will be disabled silently.
We do this in QEMU is mainly for KVM, because KVM will fail to init TD
if ATTRIBUTE.PERFMON is set.
It's expected that KVM reports PERFMON in attributes.fixed0 when KVM
cannot provide support of it. Then QEMU will print error message
automatically when validate the attributes.
For QEMU part, next version is going to set the default value of "pmu"
to false in kvm_cpu_max_instance_init(), so that "-cpu host" will not
enable pmu for TDX VMs by default.
I suppose both the KVM and QEMU change will show up in the next version.
>> +
>> QEMU_LOCK_GUARD(&tdx_guest->lock);
>> if (tdx_guest->initialized) {
>> return r;