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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Quentin, On Thu, Jul 29, 2021 at 3:28 PM Quentin Perret wrote: > > The current hypervisor stage-1 mapping code doesn't allow changing an > existing valid mapping. Relax this condition by allowing changes that > only target software bits, as that will soon be needed to annotate shared > pages. > > Signed-off-by: Quentin Perret > --- > arch/arm64/kvm/hyp/pgtable.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index 1ee1168ac32d..2689fcb7901d 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -362,6 +362,21 @@ static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep) > return 0; > } > > +static bool hyp_pte_needs_update(kvm_pte_t old, kvm_pte_t new) > +{ > + /* > + * Tolerate KVM recreating the exact same mapping, or changing software > + * bits if the existing mapping was valid. > + */ > + if (old == new) > + return false; The added comment clarifies the rationale here. Thanks. Reviewed-by: Fuad Tabba /fuad /fuad > + if (!kvm_pte_valid(old)) > + return true; > + > + return !WARN_ON((old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW); > +} > + > static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, > kvm_pte_t *ptep, struct hyp_map_data *data) > { > @@ -371,9 +386,8 @@ static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, > if (!kvm_block_mapping_supported(addr, end, phys, level)) > return false; > > - /* Tolerate KVM recreating the exact same mapping */ > new = kvm_init_valid_leaf_pte(phys, data->attr, level); > - if (old != new && !WARN_ON(kvm_pte_valid(old))) > + if (hyp_pte_needs_update(old, new)) > smp_store_release(ptep, new); > > data->phys += granule; > -- > 2.32.0.432.gabb21c7263-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel