On 2013-04-15 14:46, Paolo Bonzini wrote:
> KVM does not use the activity state VMCS field, and does not support
> it in nested VMX either (the corresponding bits in the misc VMX feature
> MSR are zero). Fail entry if the activity state is set to anything but
> "active".
Ah, that indeed simplifies the issue.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index c75c25d..589e79a 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -7223,6 +7223,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
> return 1;
> }
>
> + if (vmcs12->guest_activity_state != 0) {
GUEST_ACTIVITY_ACTIVE, please.
> + nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
> + return 1;
> + }
> +
> if ((vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_MSR_BITMAPS) &&
> !IS_ALIGNED(vmcs12->msr_bitmap, PAGE_SIZE)) {
> /*TODO: Also verify bits beyond physical address width are 0*/
>
That means we also do not need to read and write the corresponding VMCS
field on L1/L2 transitions - avoids any risk of setting it to an
unsupported value. So I would fold it into this change.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
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