Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
dereference of vmcb->control.reserved_sw before the vmcb is checked
for being non-NULL. The compiler is usually sinking the dereference
after the check; instead of doing this ourselves in the source,
ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
with a non-NULL VMCB.
Reported-by: Dan Carpenter <[email protected]>
Cc: Vineeth Pillai <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
[Untested for now due to issues with my AMD machine. - Paolo]
---
arch/x86/kvm/svm/svm.c | 4 ++--
arch/x86/kvm/svm/svm_onhyperv.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 9a6987549e1b..4bcb95bb8ed7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1406,8 +1406,6 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
goto error_free_vmsa_page;
}
- svm_vcpu_init_msrpm(vcpu, svm->msrpm);
-
svm->vmcb01.ptr = page_address(vmcb01_page);
svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);
@@ -1419,6 +1417,8 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
svm_switch_vmcb(svm, &svm->vmcb01);
init_vmcb(vcpu);
+ svm_vcpu_init_msrpm(vcpu, svm->msrpm);
+
svm_init_osvw(vcpu);
vcpu->arch.microcode_version = 0x01000065;
diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
index 9b9a55abc29f..c53b8bf8d013 100644
--- a/arch/x86/kvm/svm/svm_onhyperv.h
+++ b/arch/x86/kvm/svm/svm_onhyperv.h
@@ -89,7 +89,7 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
* as we mark it dirty unconditionally towards end of vcpu
* init phase.
*/
- if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
+ if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
hve->hv_enlightenments_control.msr_bitmap)
vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
}
--
2.27.0
Hi Paulo,
Thanks a lot for fixing this.
>
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index 9b9a55abc29f..c53b8bf8d013 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -89,7 +89,7 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
> * as we mark it dirty unconditionally towards end of vcpu
> * init phase.
> */
> - if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> + if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> hve->hv_enlightenments_control.msr_bitmap)
> vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> }
The changes looks good to me. Could you please remove the above comment
as well while you are at it.
Many Thanks,
Vineeth
Paolo Bonzini <[email protected]> writes:
> Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
> dereference of vmcb->control.reserved_sw before the vmcb is checked
> for being non-NULL. The compiler is usually sinking the dereference
> after the check; instead of doing this ourselves in the source,
> ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
> with a non-NULL VMCB.
>
> Reported-by: Dan Carpenter <[email protected]>
> Cc: Vineeth Pillai <[email protected]>
> Signed-off-by: Paolo Bonzini <[email protected]>
> [Untested for now due to issues with my AMD machine. - Paolo]
At least this doesn't seem to break kvm-amd on bare metal, so
Tested-by: Vitaly Kuznetsov <[email protected]>
> ---
> arch/x86/kvm/svm/svm.c | 4 ++--
> arch/x86/kvm/svm/svm_onhyperv.h | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 9a6987549e1b..4bcb95bb8ed7 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -1406,8 +1406,6 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
> goto error_free_vmsa_page;
> }
>
> - svm_vcpu_init_msrpm(vcpu, svm->msrpm);
> -
> svm->vmcb01.ptr = page_address(vmcb01_page);
> svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);
>
> @@ -1419,6 +1417,8 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
> svm_switch_vmcb(svm, &svm->vmcb01);
> init_vmcb(vcpu);
>
> + svm_vcpu_init_msrpm(vcpu, svm->msrpm);
> +
> svm_init_osvw(vcpu);
> vcpu->arch.microcode_version = 0x01000065;
>
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index 9b9a55abc29f..c53b8bf8d013 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -89,7 +89,7 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
> * as we mark it dirty unconditionally towards end of vcpu
> * init phase.
> */
> - if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> + if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> hve->hv_enlightenments_control.msr_bitmap)
> vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> }
--
Vitaly
On 7/27/2021 11:23 AM, Vitaly Kuznetsov wrote:
> Paolo Bonzini <[email protected]> writes:
>
>> Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
>> dereference of vmcb->control.reserved_sw before the vmcb is checked
>> for being non-NULL. The compiler is usually sinking the dereference
>> after the check; instead of doing this ourselves in the source,
>> ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
>> with a non-NULL VMCB.
>>
>> Reported-by: Dan Carpenter <[email protected]>
>> Cc: Vineeth Pillai <[email protected]>
>> Signed-off-by: Paolo Bonzini <[email protected]>
>> [Untested for now due to issues with my AMD machine. - Paolo]
Finally got hold of an AMD machine and tested nested virt: windows on
linux on
windows with the patches applied. Did basic boot and minimal verification.
Tested-by: Vineeth Pillai <[email protected]>
Thanks,
Vineeth
On 28/07/21 22:18, Vineeth Pillai wrote:
>
> On 7/27/2021 11:23 AM, Vitaly Kuznetsov wrote:
>> Paolo Bonzini <[email protected]> writes:
>>
>>> Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
>>> dereference of vmcb->control.reserved_sw before the vmcb is checked
>>> for being non-NULL. The compiler is usually sinking the dereference
>>> after the check; instead of doing this ourselves in the source,
>>> ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
>>> with a non-NULL VMCB.
>>>
>>> Reported-by: Dan Carpenter <[email protected]>
>>> Cc: Vineeth Pillai <[email protected]>
>>> Signed-off-by: Paolo Bonzini <[email protected]>
>>> [Untested for now due to issues with my AMD machine. - Paolo]
> Finally got hold of an AMD machine and tested nested virt: windows on
> linux on
> windows with the patches applied. Did basic boot and minimal verification.
>
> Tested-by: Vineeth Pillai <[email protected]>
Thanks! In the meanwhile I had fixed my machine too. :)
Paolo