On Thu, Sep 14, 2023 at 04:49:08PM +0200, Vitaly Kuznetsov wrote:
> Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx> writes:
>
> > For non VTL platforms vtl is always 0, and there is no need of
> > get_vtl function. For VTL platforms get_vtl should always succeed
> > and should return the correct VTL.
> >
> > Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
> > ---
> > arch/x86/hyperv/hv_init.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > index 783ed339f341..e589c240565a 100644
> > --- a/arch/x86/hyperv/hv_init.c
> > +++ b/arch/x86/hyperv/hv_init.c
> > @@ -416,8 +416,8 @@ static u8 __init get_vtl(void)
> > if (hv_result_success(ret)) {
> > ret = output->as64.low & HV_X64_VTL_MASK;
> > } else {
> > - pr_err("Failed to get VTL(%lld) and set VTL to zero by default.\n", ret);
> > - ret = 0;
> > + pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
>
> Nitpick: arch/x86/hyperv/hv_init.c lacks pr_fmt so the message won't get
> prefixed with "Hyper-V". I'm not sure 'VTL' abbreviation has the only,
> Hyper-V specific meaning. I'd suggest we add
>
> #define pr_fmt(fmt) "Hyper-V: " fmt
>
> to the beginning of the file.
Good suggestion, I can do this as a separate patch.
>
> > + BUG();
> > }
> >
> > local_irq_restore(flags);
> > @@ -604,8 +604,10 @@ void __init hyperv_init(void)
> > hv_query_ext_cap(0);
> >
> > /* Find the VTL */
> > - if (!ms_hyperv.paravisor_present && hv_isolation_type_snp())
> > + if (IS_ENABLED(CONFIG_HYPERV_VTL_MODE))
> > ms_hyperv.vtl = get_vtl();
> > + else
> > + ms_hyperv.vtl = 0;
>
> Is 'else' branch really needed? 'ms_hyperv' seems to be a statically
> allocated global. But instead of doing this, what about putting the
> whole get_vtl() funtion under '#if (IS_ENABLED(CONFIG_HYPERV_VTL_MODE))', i.e.:
>
> #if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
> static u8 __init get_vtl(void)
> {
> u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
> ...
> }
> #else
> static inline get_vtl(void) { return 0; }
> #endif
>
> and then we can always do
>
> ms_hyperv.vtl = get_vtl();
>
> unconditionally?
Fine with me, can update in v2.
- Saurabh
>
> >
> > return;
>
> --
> Vitaly
>
