Re: [PATCH v9 23/30] KVM: arm64: Context switch SME state for guests

[Fuad Tabba]

On Wed, 14 Jan 2026 at 17:28, Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> On Tue, Jan 13, 2026 at 02:24:56PM +0000, Fuad Tabba wrote:
> > On Tue, 23 Dec 2025 at 01:23, Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> > > +#define sme_cond_update_smcr_vq(val, reg)                      \
> > > +       do {                                                    \
> > > +               u64 __smcr = read_sysreg_s((reg));              \
> > > +               u64 __new = __smcr & ~SMCR_ELx_LEN_MASK;        \
> > > +               __new |= (val) & SMCR_ELx_LEN_MASK;             \
>
> > Similar to what I pointed out in patch 15 [1], I think you need to
> > preserve the other bits, since SMCR isn't just about the length.
>
> This does preserve the existing bits?  It reads SMCR, masks out and then
> replaces the length.

You're right. Sorry for the noise.

Cheers,
/fuad