On 9/16/15 2:42 PM, Jan Kiszka wrote:
On 2015-09-16 05:51, Wanpeng Li wrote:
Enhance allocate/free_vid to handle shadow vpid.

Signed-off-by: Wanpeng Li <wanpeng...@hotmail.com>
---
  arch/x86/kvm/vmx.c | 24 +++++++++++-------------
  1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9ff6a3f..4956081 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4155,29 +4155,27 @@ static int alloc_identity_pagetable(struct kvm *kvm)
        return r;
  }
-static void allocate_vpid(struct vcpu_vmx *vmx)
+static int allocate_vpid(void)
  {
-       int vpid;
+       int vpid = 0;
Initialization is not pointless with the current code.

- vmx->vpid = 0;
        if (!enable_vpid)
-               return;
+               return 0;
        spin_lock(&vmx_vpid_lock);
        vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
-       if (vpid < VMX_NR_VPIDS) {
-               vmx->vpid = vpid;
+       if (vpid < VMX_NR_VPIDS)
                __set_bit(vpid, vmx_vpid_bitmap);
-       }
        spin_unlock(&vmx_vpid_lock);
+       return vpid;
You should return 0 also if vpid == VMX_NR_VPIDS.

Agreed.


  }
-static void free_vpid(struct vcpu_vmx *vmx)
+static void free_vpid(int vpid)
  {
        if (!enable_vpid)
You could already test for vpid == 0 here...

                return;
        spin_lock(&vmx_vpid_lock);
-       if (vmx->vpid != 0)
-               __clear_bit(vmx->vpid, vmx_vpid_bitmap);
+       if (vpid != 0)
...then you could skip this.

Agreed.


+               __clear_bit(vpid, vmx_vpid_bitmap);
        spin_unlock(&vmx_vpid_lock);
  }
@@ -8482,7 +8480,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu) if (enable_pml)
                vmx_disable_pml(vmx);
-       free_vpid(vmx);
+       free_vpid(vmx->vpid);
        leave_guest_mode(vcpu);
        vmx_load_vmcs01(vcpu);
        free_nested(vmx);
@@ -8501,7 +8499,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, 
unsigned int id)
        if (!vmx)
                return ERR_PTR(-ENOMEM);
- allocate_vpid(vmx);
+       vmx->vpid = allocate_vpid();
err = kvm_vcpu_init(&vmx->vcpu, kvm, id);
        if (err)
@@ -8577,7 +8575,7 @@ free_msrs:
  uninit_vcpu:
        kvm_vcpu_uninit(&vmx->vcpu);
  free_vcpu:
-       free_vpid(vmx);
+       free_vpid(vmx->vpid);
        kmem_cache_free(kvm_vcpu_cache, vmx);
        return ERR_PTR(err);
  }

Yes, this is what I had in mind.

Thanks for your review. :-)

Regards,
Wanpeng Li
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