Re: [PATCH v3 27/34] KVM: selftests: Sync 'struct hv_enlightened_vmcs' definition with hyperv-tlfs.h

Maxim Levitsky
2022-05-11T12:17:41Z

On Thu, 2022-04-14 at 15:20 +0200, Vitaly Kuznetsov wrote:
> 'struct hv_enlightened_vmcs' definition in selftests is not '__packed'
> and so we rely on the compiler doing the right padding. This is not
> obvious so it seems beneficial to use the same definition as in kernel.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> tools/testing/selftests/kvm/include/x86_64/evmcs.h | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/evmcs.h b/tools/testing/selftests/kvm/include/x86_64/evmcs.h
> index cc5d14a45702..b6067b555110 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/evmcs.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/evmcs.h
> @@ -41,6 +41,8 @@ struct hv_enlightened_vmcs {
> u16 host_gs_selector;
> u16 host_tr_selector;
>
> + u16 padding16_1;
> +
> u64 host_ia32_pat;
> u64 host_ia32_efer;
>
> @@ -159,7 +161,7 @@ struct hv_enlightened_vmcs {
> u64 ept_pointer;
>
> u16 virtual_processor_id;
> - u16 padding16[3];
> + u16 padding16_2[3];
>
> u64 padding64_2[5];
> u64 guest_physical_address;
> @@ -195,15 +197,15 @@ struct hv_enlightened_vmcs {
> u64 guest_rip;
>
> u32 hv_clean_fields;
> - u32 hv_padding_32;
> + u32 padding32_1;
> u32 hv_synthetic_controls;
> struct {
> u32 nested_flush_hypercall:1;
> u32 msr_bitmap:1;
> u32 reserved:30;
> - } hv_enlightenments_control;
> + } __packed hv_enlightenments_control;
> u32 hv_vp_id;
> -
> + u32 padding32_2;
> u64 hv_vm_id;
> u64 partition_assist_page;
> u64 padding64_4[4];
> @@ -211,7 +213,7 @@ struct hv_enlightened_vmcs {
> u64 padding64_5[7];
> u64 xss_exit_bitmap;
> u64 padding64_6[7];
> -};
> +} __packed;
>
> #define HV_VMX_ENLIGHTENED_CLEAN_FIELD_NONE 0
> #define HV_VMX_ENLIGHTENED_CLEAN_FIELD_IO_BITMAP BIT(0)

Makes sense.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
Maxim Levitsky