"VMXON pointer" is saved in vmx->nested.vmxon_ptr since
commit 3573e22cfeca ("KVM: nVMX: additional checks on
vmxon region"). Also, handle_vmptrld() & handle_vmclear()
now have logic to check the VMCS pointer against the VMXON
pointer.
So just remove the obsolete comments of handle_vmon().
Signed-off-by: Yu Zhang <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index bc6327950657..90f34f12f883 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4862,14 +4862,7 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
return -ENOMEM;
}
-/*
- * Emulate the VMXON instruction.
- * Currently, we just remember that VMX is active, and do not save or even
- * inspect the argument to VMXON (the so-called "VMXON pointer") because we
- * do not currently need to store anything in that guest-allocated memory
- * region. Consequently, VMCLEAR and VMPTRLD also do not verify that the their
- * argument is different from the VMXON pointer (which the spec says they do).
- */
+/* Emulate the VMXON instruction. */
static int handle_vmon(struct kvm_vcpu *vcpu)
{
int ret;
--
2.17.1
Yu Zhang <[email protected]> writes:
> "VMXON pointer" is saved in vmx->nested.vmxon_ptr since
> commit 3573e22cfeca ("KVM: nVMX: additional checks on
> vmxon region"). Also, handle_vmptrld() & handle_vmclear()
> now have logic to check the VMCS pointer against the VMXON
> pointer.
>
> So just remove the obsolete comments of handle_vmon().
>
> Signed-off-by: Yu Zhang <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index bc6327950657..90f34f12f883 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -4862,14 +4862,7 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
> return -ENOMEM;
> }
>
> -/*
> - * Emulate the VMXON instruction.
> - * Currently, we just remember that VMX is active, and do not save or even
> - * inspect the argument to VMXON (the so-called "VMXON pointer") because we
> - * do not currently need to store anything in that guest-allocated memory
> - * region. Consequently, VMCLEAR and VMPTRLD also do not verify that the their
> - * argument is different from the VMXON pointer (which the spec says they do).
> - */
> +/* Emulate the VMXON instruction. */
> static int handle_vmon(struct kvm_vcpu *vcpu)
> {
> int ret;
Indeed,
Reviewed-by: Vitaly Kuznetsov <[email protected]>
On a slightly related note: we don't seem to reset
'vmx->nested.vmxon_ptr' upon VMXOFF emulation; this is not a problem per
se as we never access it when !vmx->nested.vmxon but I'd still suggest
we do something like
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index bc6327950657..8beb41d02d21 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -290,6 +290,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
vmx->nested.vmxon = false;
vmx->nested.smm.vmxon = false;
+ vmx->nested.vmxon_ptr = -1ull;
free_vpid(vmx->nested.vpid02);
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d7c5257eb5c0..2214e6bd4713 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6884,6 +6884,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
vcpu_setup_sgx_lepubkeyhash(vcpu);
+ vmx->nested.vmxon_ptr = -1ull;
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID;
to avoid issues in the future.
--
Vitaly
On Wed, Sep 08, 2021 at 11:55:59AM +0200, Vitaly Kuznetsov wrote:
> Indeed,
>
> Reviewed-by: Vitaly Kuznetsov <[email protected]>
>
> On a slightly related note: we don't seem to reset
> 'vmx->nested.vmxon_ptr' upon VMXOFF emulation; this is not a problem per
> se as we never access it when !vmx->nested.vmxon but I'd still suggest
> we do something like
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index bc6327950657..8beb41d02d21 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -290,6 +290,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
>
> vmx->nested.vmxon = false;
> vmx->nested.smm.vmxon = false;
> + vmx->nested.vmxon_ptr = -1ull;
> free_vpid(vmx->nested.vpid02);
> vmx->nested.posted_intr_nv = -1;
> vmx->nested.current_vmptr = -1ull;
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index d7c5257eb5c0..2214e6bd4713 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6884,6 +6884,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
>
> vcpu_setup_sgx_lepubkeyhash(vcpu);
>
> + vmx->nested.vmxon_ptr = -1ull;
> vmx->nested.posted_intr_nv = -1;
> vmx->nested.current_vmptr = -1ull;
> vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID;
>
> to avoid issues in the future.
>
Thanks, Vitaly. And above suggestion sounds reasonable to me. :)
I can add this in V2 later, if no one objects.
B.R.
Yu
Yu Zhang <[email protected]> writes:
> On Wed, Sep 08, 2021 at 11:55:59AM +0200, Vitaly Kuznetsov wrote:
>> Indeed,
>>
>> Reviewed-by: Vitaly Kuznetsov <[email protected]>
>>
>> On a slightly related note: we don't seem to reset
>> 'vmx->nested.vmxon_ptr' upon VMXOFF emulation; this is not a problem per
>> se as we never access it when !vmx->nested.vmxon but I'd still suggest
>> we do something like
>>
>> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>> index bc6327950657..8beb41d02d21 100644
>> --- a/arch/x86/kvm/vmx/nested.c
>> +++ b/arch/x86/kvm/vmx/nested.c
>> @@ -290,6 +290,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
>>
>> vmx->nested.vmxon = false;
>> vmx->nested.smm.vmxon = false;
>> + vmx->nested.vmxon_ptr = -1ull;
>> free_vpid(vmx->nested.vpid02);
>> vmx->nested.posted_intr_nv = -1;
>> vmx->nested.current_vmptr = -1ull;
>> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
>> index d7c5257eb5c0..2214e6bd4713 100644
>> --- a/arch/x86/kvm/vmx/vmx.c
>> +++ b/arch/x86/kvm/vmx/vmx.c
>> @@ -6884,6 +6884,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
>>
>> vcpu_setup_sgx_lepubkeyhash(vcpu);
>>
>> + vmx->nested.vmxon_ptr = -1ull;
>> vmx->nested.posted_intr_nv = -1;
>> vmx->nested.current_vmptr = -1ull;
>> vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID;
>>
>> to avoid issues in the future.
>>
> Thanks, Vitaly. And above suggestion sounds reasonable to me. :)
>
> I can add this in V2 later, if no one objects.
>
Sure, this is rather a separate patch. Thanks!
--
Vitaly
On Wed, Sep 08, 2021 at 03:42:13PM +0200, Vitaly Kuznetsov wrote:
>
> Sure, this is rather a separate patch. Thanks!
Oh, right. Just sent out a seperate patch. :)
@Paolo Any comment on this one? Thanks!
B.R.
Yu
On 08/09/21 19:17, Yu Zhang wrote:
> "VMXON pointer" is saved in vmx->nested.vmxon_ptr since
> commit 3573e22cfeca ("KVM: nVMX: additional checks on
> vmxon region"). Also, handle_vmptrld() & handle_vmclear()
> now have logic to check the VMCS pointer against the VMXON
> pointer.
>
> So just remove the obsolete comments of handle_vmon().
>
> Signed-off-by: Yu Zhang <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 9 +--------
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index bc6327950657..90f34f12f883 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -4862,14 +4862,7 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
> return -ENOMEM;
> }
>
> -/*
> - * Emulate the VMXON instruction.
> - * Currently, we just remember that VMX is active, and do not save or even
> - * inspect the argument to VMXON (the so-called "VMXON pointer") because we
> - * do not currently need to store anything in that guest-allocated memory
> - * region. Consequently, VMCLEAR and VMPTRLD also do not verify that the their
> - * argument is different from the VMXON pointer (which the spec says they do).
> - */
> +/* Emulate the VMXON instruction. */
> static int handle_vmon(struct kvm_vcpu *vcpu)
> {
> int ret;
>
Queued, thanks.
Paolo