Re: [PATCH v2 1/2] KVM: nVMX: enhance allocate/free_vpid to handle shadow vpid

[Wanpeng Li]

On 9/15/15 8:54 PM, Paolo Bonzini wrote:


On 15/09/2015 12:30, Wanpeng Li wrote:

+   if (!nested) {
+   vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+   if (vpid < VMX_NR_VPIDS) {
vmx->vpid = vpid;
__set_bit(vpid, vmx_vpid_bitmap);
+   }
+   } else {
+   vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+   if (vpid < VMX_NR_VPIDS) {
+   vmx->nested.vpid02 = vpid;
+   __set_bit(vpid, vmx_vpid_bitmap);
+   }

Messy indentation, and a lot of duplicate code.  Can you instead have
(which I think was Jan's suggestion too):

static int allocate_vpid(void);
static void free_vpid(int vpid);


I see, done in v3.



That said, I like the simple solution to the "too many VPIDs for each L1
VCPU" processor.


Thanks. :-)

Regards,
Wanpeng Li

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[PATCH v2 1/2] KVM: nVMX: enhance allocate/free_vpid to handle shadow vpid

[Wanpeng Li]

Enhance allocate/free_vid to handle shadow vpid.

Suggested-by: Wincy Van 
Signed-off-by: Wanpeng Li 
---
 arch/x86/kvm/vmx.c | 33 +++--
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index da1590e..bd07d88 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -424,6 +424,8 @@ struct nested_vmx {
/* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */
u64 vmcs01_debugctl;
 
+   u16 vpid02;
+
u32 nested_vmx_procbased_ctls_low;
u32 nested_vmx_procbased_ctls_high;
u32 nested_vmx_true_procbased_ctls_low;
@@ -4155,18 +4157,29 @@ static int alloc_identity_pagetable(struct kvm *kvm)
return r;
 }
 
-static void allocate_vpid(struct vcpu_vmx *vmx)
+static void allocate_vpid(struct vcpu_vmx *vmx, bool nested)
 {
int vpid;
 
-   vmx->vpid = 0;
if (!enable_vpid)
return;
+   if (!nested)
+   vmx->vpid = 0;
+   else
+   vmx->nested.vpid02 = 0;
spin_lock(_vpid_lock);
-   vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
-   if (vpid < VMX_NR_VPIDS) {
+   if (!nested) {
+   vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+   if (vpid < VMX_NR_VPIDS) {
vmx->vpid = vpid;
__set_bit(vpid, vmx_vpid_bitmap);
+   }
+   } else {
+   vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+   if (vpid < VMX_NR_VPIDS) {
+   vmx->nested.vpid02 = vpid;
+   __set_bit(vpid, vmx_vpid_bitmap);
+   }
}
spin_unlock(_vpid_lock);
 }
@@ -4178,6 +4191,12 @@ static void free_vpid(struct vcpu_vmx *vmx)
spin_lock(_vpid_lock);
if (vmx->vpid != 0)
__clear_bit(vmx->vpid, vmx_vpid_bitmap);
+   if (!nested) {
+   spin_unlock(_vpid_lock);
+   return;
+   }
+   if (vmx->nested.vpid02)
+   __clear_bit(vmx->nested.vpid02, vmx_vpid_bitmap);
spin_unlock(_vpid_lock);
 }
 
@@ -8509,7 +8528,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, 
unsigned int id)
if (!vmx)
return ERR_PTR(-ENOMEM);
 
-   allocate_vpid(vmx);
+   allocate_vpid(vmx, false);
 
err = kvm_vcpu_init(>vcpu, kvm, id);
if (err)
@@ -8557,8 +8576,10 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, 
unsigned int id)
goto free_vmcs;
}
 
-   if (nested)
+   if (nested) {
nested_vmx_setup_ctls_msrs(vmx);
+   allocate_vpid(vmx, true);
+   }
 
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
-- 
1.9.1

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Re: [PATCH v2 1/2] KVM: nVMX: enhance allocate/free_vpid to handle shadow vpid

[Paolo Bonzini]

On 15/09/2015 12:30, Wanpeng Li wrote:
> + if (!nested) {
> + vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
> + if (vpid < VMX_NR_VPIDS) {
>   vmx->vpid = vpid;
>   __set_bit(vpid, vmx_vpid_bitmap);
> + }
> + } else {
> + vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
> + if (vpid < VMX_NR_VPIDS) {
> + vmx->nested.vpid02 = vpid;
> + __set_bit(vpid, vmx_vpid_bitmap);
> + }

Messy indentation, and a lot of duplicate code.  Can you instead have
(which I think was Jan's suggestion too):

static int allocate_vpid(void);
static void free_vpid(int vpid);

That said, I like the simple solution to the "too many VPIDs for each L1
VCPU" processor.

Paolo
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