Re: [PATCH v7 053/102] KVM: TDX: don't request KVM_REQ_APIC_PAGE_RELOAD

Chao Gao
2022-07-12T06:15:13Z

On Tue, Jul 12, 2022 at 11:47:43AM +0800, Yuan Yao wrote:
>On Mon, Jun 27, 2022 at 02:53:45PM -0700, isaku.yamahata@intel.com wrote:
>> From: Isaku Yamahata <isaku.yamahata@intel.com>
>>
>> TDX doesn't need APIC page depending on vapic and its callback is
>> WARN_ON_ONCE(is_tdx). To avoid unnecessary overhead and WARN_ON_ONCE(),
>> skip requesting KVM_REQ_APIC_PAGE_RELOAD when TD.

!kvm_gfn_shared_mask() doesn't ensure the VM is a TD. Right?

>>
>>
>> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
>> ---
>> arch/x86/kvm/x86.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 8f57dfb2a8c9..c90ec611de2f 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -10042,7 +10042,8 @@ void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>> * Update it when it becomes invalid.
>> */
>> apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
>> - if (start <= apic_address && apic_address < end)
>> + if (start <= apic_address && apic_address < end &&
>> + !kvm_gfn_shared_mask(kvm))
>
>Minor: please condier to check kvm_gfn_shared_mask(kvm) before range,
>means firstly check is or not, then suitable or not.
>
>> kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
>> }
>>
>> --
>> 2.25.1
>>