2019-09-26 09:46:58

by Paolo Bonzini

Subject: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
IA32_EFER" exit control was reset. Also, some checks were not using
the new CC macro for tracing.

Cleanup everything so that the vCPU's 64-bit mode is determined
directly from EFER_LMA and the VMCS checks are based on that, which
matches section 26.2.4 of the SDM.

Cc: Sean Christopherson <[email protected]>
Cc: Jim Mattson <[email protected]>
Cc: Krish Sadhukhan <[email protected]>
Fixes: 5845038c111db27902bc220a4f70070fe945871c
Signed-off-by: Paolo Bonzini <[email protected]>
---
arch/x86/kvm/vmx/nested.c | 53 ++++++++++++++++++++---------------------------
1 file changed, 22 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 70d59d9304f2..e108847f6cf8 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2664,8 +2664,26 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
CC(!kvm_pat_valid(vmcs12->host_ia32_pat)))
return -EINVAL;

- ia32e = (vmcs12->vm_exit_controls &
- VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
+#ifdef CONFIG_X86_64
+ ia32e = !!(vcpu->arch.efer & EFER_LMA);
+#else
+ if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE))
+ return -EINVAL;
+
+ ia32e = false;
+#endif
+
+ if (ia32e) {
+ if (CC(!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) ||
+ CC(!(vmcs12->host_cr4 & X86_CR4_PAE)))
+ return -EINVAL;
+ } else {
+ if (CC(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) ||
+ CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
+ CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
+ CC(((vmcs12->host_rip) >> 32) & 0xffffffff))
+ return -EINVAL;
+ }

if (CC(vmcs12->host_cs_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
CC(vmcs12->host_ss_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
@@ -2684,35 +2702,8 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
CC(is_noncanonical_address(vmcs12->host_gs_base, vcpu)) ||
CC(is_noncanonical_address(vmcs12->host_gdtr_base, vcpu)) ||
CC(is_noncanonical_address(vmcs12->host_idtr_base, vcpu)) ||
- CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)))
- return -EINVAL;
-
- if (!(vmcs12->host_ia32_efer & EFER_LMA) &&
- ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
- (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE))) {
- return -EINVAL;
- }
-
- if ((vmcs12->host_ia32_efer & EFER_LMA) &&
- !(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) {
- return -EINVAL;
- }
-
- if (!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
- ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
- (vmcs12->host_cr4 & X86_CR4_PCIDE) ||
- (((vmcs12->host_rip) >> 32) & 0xffffffff))) {
- return -EINVAL;
- }
-
- if ((vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
- ((!(vmcs12->host_cr4 & X86_CR4_PAE)) ||
- (is_noncanonical_address(vmcs12->host_rip, vcpu)))) {
- return -EINVAL;
- }
-#else
- if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE ||
- vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
+ CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->host_rip, vcpu)))
return -EINVAL;
#endif

--
1.8.3.1

2019-09-26 10:07:46

by Krish Sadhukhan

Subject: Re: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

On 09/25/2019 09:47 AM, Jim Mattson wrote:
> On Wed, Sep 25, 2019 at 9:34 AM Paolo Bonzini <[email protected]> wrote:
>> KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
>> IA32_EFER" exit control was reset. Also, some checks were not using
>> the new CC macro for tracing.
>>
>> Cleanup everything so that the vCPU's 64-bit mode is determined
>> directly from EFER_LMA and the VMCS checks are based on that, which
>> matches section 26.2.4 of the SDM.
>>
>> Cc: Sean Christopherson <[email protected]>
>> Cc: Jim Mattson <[email protected]>
>> Cc: Krish Sadhukhan <[email protected]>
>> Fixes: 5845038c111db27902bc220a4f70070fe945871c
>> Signed-off-by: Paolo Bonzini <[email protected]>
>> ---
>> arch/x86/kvm/vmx/nested.c | 53 ++++++++++++++++++++---------------------------
>> 1 file changed, 22 insertions(+), 31 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>> index 70d59d9304f2..e108847f6cf8 100644
>> --- a/arch/x86/kvm/vmx/nested.c
>> +++ b/arch/x86/kvm/vmx/nested.c
>> @@ -2664,8 +2664,26 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
>> CC(!kvm_pat_valid(vmcs12->host_ia32_pat)))
>> return -EINVAL;
>>
>> - ia32e = (vmcs12->vm_exit_controls &
>> - VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
>> +#ifdef CONFIG_X86_64
>> + ia32e = !!(vcpu->arch.efer & EFER_LMA);
>> +#else
>> + if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE))
>> + return -EINVAL;
> This check is redundant, since it is checked in the else block below.

Should we be re-using is_long_mode() instead of duplicating the code ?

>
>> +
>> + ia32e = false;
>> +#endif
>> +
>> + if (ia32e) {
>> + if (CC(!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) ||
>> + CC(!(vmcs12->host_cr4 & X86_CR4_PAE)))
>> + return -EINVAL;
>> + } else {
>> + if (CC(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) ||
>> + CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
>> + CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
>> + CC(((vmcs12->host_rip) >> 32) & 0xffffffff))
> The mask shouldn't be necessary.
>
>> + return -EINVAL;
>> + }
>>
>> if (CC(vmcs12->host_cs_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
>> CC(vmcs12->host_ss_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
>> @@ -2684,35 +2702,8 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
>> CC(is_noncanonical_address(vmcs12->host_gs_base, vcpu)) ||
>> CC(is_noncanonical_address(vmcs12->host_gdtr_base, vcpu)) ||
>> CC(is_noncanonical_address(vmcs12->host_idtr_base, vcpu)) ||
>> - CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)))
>> - return -EINVAL;
>> -
>> - if (!(vmcs12->host_ia32_efer & EFER_LMA) &&
>> - ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
>> - (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE))) {
>> - return -EINVAL;
>> - }
>> -
>> - if ((vmcs12->host_ia32_efer & EFER_LMA) &&
>> - !(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) {
>> - return -EINVAL;
>> - }
>> -
>> - if (!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
>> - ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
>> - (vmcs12->host_cr4 & X86_CR4_PCIDE) ||
>> - (((vmcs12->host_rip) >> 32) & 0xffffffff))) {
>> - return -EINVAL;
>> - }
>> -
>> - if ((vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
>> - ((!(vmcs12->host_cr4 & X86_CR4_PAE)) ||
>> - (is_noncanonical_address(vmcs12->host_rip, vcpu)))) {
>> - return -EINVAL;
>> - }
>> -#else
>> - if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE ||
>> - vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
>> + CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)) ||
>> + CC(is_noncanonical_address(vmcs12->host_rip, vcpu)))
>> return -EINVAL;
>> #endif
>>
>> --
>> 1.8.3.1
>>
> Reviewed-by: Jim Mattson <[email protected]>

2019-09-26 10:29:23

by Paolo Bonzini

Subject: Re: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

On 26/09/19 01:55, Krish Sadhukhan wrote:
>
>
> On 09/25/2019 09:47 AM, Jim Mattson wrote:
>> On Wed, Sep 25, 2019 at 9:34 AM Paolo Bonzini <[email protected]>
>> wrote:
>>> KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
>>> IA32_EFER" exit control was reset.  Also, some checks were not using
>>> the new CC macro for tracing.
>>>
>>> Cleanup everything so that the vCPU's 64-bit mode is determined
>>> directly from EFER_LMA and the VMCS checks are based on that, which
>>> matches section 26.2.4 of the SDM.
>>>
>>> Cc: Sean Christopherson <[email protected]>
>>> Cc: Jim Mattson <[email protected]>
>>> Cc: Krish Sadhukhan <[email protected]>
>>> Fixes: 5845038c111db27902bc220a4f70070fe945871c
>>> Signed-off-by: Paolo Bonzini <[email protected]>
>>> ---
>>>   arch/x86/kvm/vmx/nested.c | 53
>>> ++++++++++++++++++++---------------------------
>>>   1 file changed, 22 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>>> index 70d59d9304f2..e108847f6cf8 100644
>>> --- a/arch/x86/kvm/vmx/nested.c
>>> +++ b/arch/x86/kvm/vmx/nested.c
>>> @@ -2664,8 +2664,26 @@ static int nested_vmx_check_host_state(struct
>>> kvm_vcpu *vcpu,
>>>              CC(!kvm_pat_valid(vmcs12->host_ia32_pat)))
>>>                  return -EINVAL;
>>>
>>> -       ia32e = (vmcs12->vm_exit_controls &
>>> -                VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
>>> +#ifdef CONFIG_X86_64
>>> +       ia32e = !!(vcpu->arch.efer & EFER_LMA);
>>> +#else
>>> +       if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE))
>>> +               return -EINVAL;
>> This check is redundant, since it is checked in the else block below.
>
> Should we be re-using is_long_mode() instead of duplicating the code ?

Of course! I have already pushed the patch, but I will send a follow up.

Paolo

2019-09-26 10:56:58

by Jim Mattson

Subject: Re: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

On Wed, Sep 25, 2019 at 9:34 AM Paolo Bonzini <[email protected]> wrote:
>
> KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
> IA32_EFER" exit control was reset. Also, some checks were not using
> the new CC macro for tracing.
>
> Cleanup everything so that the vCPU's 64-bit mode is determined
> directly from EFER_LMA and the VMCS checks are based on that, which
> matches section 26.2.4 of the SDM.
>
> Cc: Sean Christopherson <[email protected]>
> Cc: Jim Mattson <[email protected]>
> Cc: Krish Sadhukhan <[email protected]>
> Fixes: 5845038c111db27902bc220a4f70070fe945871c
> Signed-off-by: Paolo Bonzini <[email protected]>
> ---
> arch/x86/kvm/vmx/nested.c | 53 ++++++++++++++++++++---------------------------
> 1 file changed, 22 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 70d59d9304f2..e108847f6cf8 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2664,8 +2664,26 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
> CC(!kvm_pat_valid(vmcs12->host_ia32_pat)))
> return -EINVAL;
>
> - ia32e = (vmcs12->vm_exit_controls &
> - VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
> +#ifdef CONFIG_X86_64
> + ia32e = !!(vcpu->arch.efer & EFER_LMA);
> +#else
> + if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE))
> + return -EINVAL;

This check is redundant, since it is checked in the else block below.

> +
> + ia32e = false;
> +#endif
> +
> + if (ia32e) {
> + if (CC(!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) ||
> + CC(!(vmcs12->host_cr4 & X86_CR4_PAE)))
> + return -EINVAL;
> + } else {
> + if (CC(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) ||
> + CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
> + CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
> + CC(((vmcs12->host_rip) >> 32) & 0xffffffff))

The mask shouldn't be necessary.

> + return -EINVAL;
> + }
>
> if (CC(vmcs12->host_cs_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
> CC(vmcs12->host_ss_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
> @@ -2684,35 +2702,8 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
> CC(is_noncanonical_address(vmcs12->host_gs_base, vcpu)) ||
> CC(is_noncanonical_address(vmcs12->host_gdtr_base, vcpu)) ||
> CC(is_noncanonical_address(vmcs12->host_idtr_base, vcpu)) ||
> - CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)))
> - return -EINVAL;
> -
> - if (!(vmcs12->host_ia32_efer & EFER_LMA) &&
> - ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
> - (vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE))) {
> - return -EINVAL;
> - }
> -
> - if ((vmcs12->host_ia32_efer & EFER_LMA) &&
> - !(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)) {
> - return -EINVAL;
> - }
> -
> - if (!(vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
> - ((vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
> - (vmcs12->host_cr4 & X86_CR4_PCIDE) ||
> - (((vmcs12->host_rip) >> 32) & 0xffffffff))) {
> - return -EINVAL;
> - }
> -
> - if ((vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE) &&
> - ((!(vmcs12->host_cr4 & X86_CR4_PAE)) ||
> - (is_noncanonical_address(vmcs12->host_rip, vcpu)))) {
> - return -EINVAL;
> - }
> -#else
> - if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE ||
> - vmcs12->vm_exit_controls & VM_EXIT_HOST_ADDR_SPACE_SIZE)
> + CC(is_noncanonical_address(vmcs12->host_tr_base, vcpu)) ||
> + CC(is_noncanonical_address(vmcs12->host_rip, vcpu)))
> return -EINVAL;
> #endif
>
> --
> 1.8.3.1
>
Reviewed-by: Jim Mattson <[email protected]>

2019-09-26 11:34:52

by Liran Alon

Subject: Re: [PATCH] KVM: nVMX: cleanup and fix host 64-bit mode checks

> On 25 Sep 2019, at 19:34, Paolo Bonzini <[email protected]> wrote:
>
> KVM was incorrectly checking vmcs12->host_ia32_efer even if the "load
> IA32_EFER" exit control was reset. Also, some checks were not using
> the new CC macro for tracing.
>
> Cleanup everything so that the vCPU's 64-bit mode is determined
> directly from EFER_LMA and the VMCS checks are based on that, which
> matches section 26.2.4 of the SDM.
>
> Cc: Sean Christopherson <[email protected]>
> Cc: Jim Mattson <[email protected]>
> Cc: Krish Sadhukhan <[email protected]>
> Fixes: 5845038c111db27902bc220a4f70070fe945871c
> Signed-off-by: Paolo Bonzini <[email protected]>
> —

Reviewed-by: Liran Alon <[email protected]>