On Wed, Mar 23, 2022 at 08:46:40PM +0800, Gavin Shan wrote:
> Hi Oliver,
>
> On 3/23/22 2:04 AM, Oliver Upton wrote:
> > On Tue, Mar 22, 2022 at 04:06:51PM +0800, Gavin Shan wrote:
> > > This supports SDEI_VERSION hypercall by returning v1.1, which is
> > > the specification version we're following. The vendor is set to
> > > 'KVM'.
> > >
> > > Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
> > > ---
> > > arch/arm64/kvm/sdei.c | 10 ++++++++++
> > > 1 file changed, 10 insertions(+)
> > >
> > > diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> > > index 8a9b477b8977..5a3a64cd6e84 100644
> > > --- a/arch/arm64/kvm/sdei.c
> > > +++ b/arch/arm64/kvm/sdei.c
> > > @@ -118,6 +118,14 @@ static bool remove_all_vcpu_events(struct kvm_vcpu *vcpu,
> > > return pending;
> > > }
> > > +static unsigned long hypercall_version(struct kvm_vcpu *vcpu)
> > > +{
> > > + /* v1.1 and the vendor is KVM */
> > > + return (1UL << SDEI_VERSION_MAJOR_SHIFT) |
> > > + (1UL << SDEI_VERSION_MINOR_SHIFT) |
> > > + 0x4b564d;
> >
> > It looks like the SDEI specification states that the vendor-defined
> > version number is 32 bits. Could we just use one of the
> > ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_{0,3} values instead?
> >
> > ASCII 'KVM' is neat, but in reality guest software will just throw it in
> > a macro regardless. Might as well use one of the values we've already
> > trained it to use :-)
> >
> > Also, it would appear that guest discovery of SDEI relies upon KVM
> > reporting a valid SDEI version. IMO, this patch should come at the very
> > end when KVM actually implements SDEI.
> >
>
> Yeah, I was sticky to the pattern of "KVM". However, I think it's good
> to reuse the existing one. Lets use ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2
> if you agree. Its first two characters are "VM" at least.
Sounds fine to me. The only other nit I'd say is we should define a
macro for it too, something like:
#define KVM_SDEI_VENDOR ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2
--
Thanks,
Oliver
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