Re: [PATCH v2 3/5] LoongArch: KVM: Add separate vmid feature support

On 2026/8/6 下午8:23, Huacai Chen wrote:
> Hi, Bibo,
> 
> On Thu, Aug 6, 2026 at 10:15 AM Bibo Mao <[email protected]> wrote:
>>
>> Feature cpu_has_guestid is used to check whether separate vmid/vpid
>> is supported or not. It is disabled by default, add this feature
>> checking, there is no function change.
>>
>> Signed-off-by: Bibo Mao <[email protected]>
>> ---
>>   arch/loongarch/kvm/main.c | 14 +++++++++-----
>>   arch/loongarch/kvm/mmu.c  |  6 ++++--
>>   arch/loongarch/kvm/vcpu.c |  3 ++-
>>   3 files changed, 15 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
>> index ac804e77e844..c36e62ab0d91 100644
>> --- a/arch/loongarch/kvm/main.c
>> +++ b/arch/loongarch/kvm/main.c
>> @@ -218,7 +218,8 @@ static void kvm_update_vpid(struct kvm_vcpu *vcpu, int cpu)
>>                  ++vpid; /* vpid 0 reserved for root */
>>
>>                  /* start new vpid cycle */
>> -               kvm_flush_tlb_all();
>> +               if (!cpu_has_guestid)
>> +                       kvm_flush_tlb_all();
>>          }
>>
>>          context->vpid_cache = vpid;
>> @@ -282,10 +283,13 @@ static void __kvm_check_vmid(struct kvm_vcpu *vcpu)
>>   {
>>          unsigned long vmid;
>>
>> -       vmid = vcpu->arch.vpid & vpid_mask;
>> -       if (vcpu->arch.hw_vmid != vmid) {
>> -               vcpu->arch.hw_vmid = vcpu->arch.vpid & vpid_mask;
>> -               kvm_clear_request(KVM_REQ_TLB_FLUSH_GPA, vcpu);
>> +       /* On some machines like 3A5000, vmid needs the same with vpid */
>> +       if (!cpu_has_guestid) {
>> +               vmid = vcpu->arch.vpid & vpid_mask;
>> +               if (vcpu->arch.hw_vmid != vmid) {
>> +                       vcpu->arch.hw_vmid = vcpu->arch.vpid & vpid_mask;
>> +                       kvm_clear_request(KVM_REQ_TLB_FLUSH_GPA, vcpu);
>> +               }
> Merge Patch#3 and Patch#4, then __kvm_check_vmid() can handle both
> cpu_has_guestid and !cpu_has_guestid cases together.
will merge Patch#3 and Patch#4 together in next version.

Regards
Bibo Mao

> 
> 
> Huacai
> 
>>          }
>>   }
>>
>> diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c
>> index e104897aa532..714640a2e614 100644
>> --- a/arch/loongarch/kvm/mmu.c
>> +++ b/arch/loongarch/kvm/mmu.c
>> @@ -929,8 +929,10 @@ int kvm_handle_mm_fault(struct kvm_vcpu *vcpu, unsigned long gpa, bool write, in
>>                   *
>>                   * With SW PTW, invalid TLB is added in TLB refill exception.
>>                   */
>> -               vcpu->arch.flush_gpa = gpa;
>> -               kvm_make_request(KVM_REQ_TLB_FLUSH_GPA, vcpu);
>> +               if (!cpu_has_guestid) {
>> +                       vcpu->arch.flush_gpa = gpa;
>> +                       kvm_make_request(KVM_REQ_TLB_FLUSH_GPA, vcpu);
>> +               }
>>          }
>>
>>          return 0;
>> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
>> index 20c207d80e31..0b2355aec932 100644
>> --- a/arch/loongarch/kvm/vcpu.c
>> +++ b/arch/loongarch/kvm/vcpu.c
>> @@ -210,7 +210,8 @@ static int kvm_check_requests(struct kvm_vcpu *vcpu)
>>                  return RESUME_GUEST;
>>
>>          if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu))
>> -               vcpu->arch.vpid = 0;  /* Drop vpid for this vCPU */
>> +               if (!cpu_has_guestid)
>> +                       vcpu->arch.vpid = 0;  /* Drop vpid for this vCPU */
>>
>>          if (kvm_dirty_ring_check_request(vcpu))
>>                  return RESUME_HOST;
>> --
>> 2.39.3
>>