On Tuesday 17 Dec 2024 at 10:52:08 (+0000), Marc Zyngier wrote:
> On Mon, 16 Dec 2024 17:57:46 +0000,
> Quentin Perret <qperret@google.com> wrote:
> >
> > The 'concrete' (a.k.a non-meta) page states are currently encoded using
> > software bits in PTEs. For performance reasons, the abstract
> > pkvm_page_state enum uses the same bits to encode these states as that
> > makes conversions from and to PTEs easy.
> >
> > In order to prepare the ground for moving the 'concrete' state storage
> > to the hyp vmemmap, re-arrange the enum to use bits 0 and 1 for this
> > purpose.
> >
> > No functional changes intended.
> >
> > Signed-off-by: Quentin Perret <qperret@google.com>
> > ---
> > arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 16 +++++++++-------
> > 1 file changed, 9 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > index 0972faccc2af..8c30362af2b9 100644
> > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> > @@ -24,25 +24,27 @@
> > */
> > enum pkvm_page_state {
> > PKVM_PAGE_OWNED = 0ULL,
> > - PKVM_PAGE_SHARED_OWNED = KVM_PGTABLE_PROT_SW0,
> > - PKVM_PAGE_SHARED_BORROWED = KVM_PGTABLE_PROT_SW1,
> > - __PKVM_PAGE_RESERVED = KVM_PGTABLE_PROT_SW0 |
> > - KVM_PGTABLE_PROT_SW1,
> > + PKVM_PAGE_SHARED_OWNED = BIT(0),
> > + PKVM_PAGE_SHARED_BORROWED = BIT(1),
> > + __PKVM_PAGE_RESERVED = BIT(0) | BIT(1),
> >
> > /* Meta-states which aren't encoded directly in the PTE's SW bits */
> > - PKVM_NOPAGE,
> > + PKVM_NOPAGE = BIT(2),
> > };
> > +#define PKVM_PAGE_META_STATES_MASK (~(BIT(0) | BIT(1)))
>
> Shouldn't that be ~__PKVM_PAGE_RESERVED, given that you just defined it?
Sure thing, I followed the same pattern as PKVM_PAGE_STATE_PROT_MASK
which was explicit in which bits it sets, but very happy to change.
> >
> > #define PKVM_PAGE_STATE_PROT_MASK (KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)
> > static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,
> > enum pkvm_page_state state)
> > {
> > - return (prot & ~PKVM_PAGE_STATE_PROT_MASK) | state;
> > + prot &= ~PKVM_PAGE_STATE_PROT_MASK;
> > + prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state);
> > + return prot;
> > }
> >
> > static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
> > {
> > - return prot & PKVM_PAGE_STATE_PROT_MASK;
> > + return FIELD_GET(PKVM_PAGE_STATE_PROT_MASK, prot);
> > }
> >
> > struct host_mmu {
>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.