[PATCH v13 01/35] KVM: Tweak kvm_hva_range and hva_handler_t to allow reusing for gfn ranges

[Fuad Tabba]

On Fri, Oct 27, 2023 at 7:22 PM Sean Christopherson <seanjc at google.com> wrote:
>
> Rework and rename "struct kvm_hva_range" into "kvm_mmu_notifier_range" so
> that the structure can be used to handle notifications that operate on gfn
> context, i.e. that aren't tied to a host virtual address.  Rename the
> handler typedef too (arguably it should always have been gfn_handler_t).
>
> Practically speaking, this is a nop for 64-bit kernels as the only
> meaningful change is to store start+end as u64s instead of unsigned longs.
>
> Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>
> Reviewed-by: Xiaoyao Li <xiaoyao.li at intel.com>
> Signed-off-by: Sean Christopherson <seanjc at google.com>
> ---

Reviewed-by: Fuad Tabba <tabba at google.com>
Tested-by: Fuad Tabba <tabba at google.com>

Cheers,
/fuad


>  virt/kvm/kvm_main.c | 34 +++++++++++++++++++---------------
>  1 file changed, 19 insertions(+), 15 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 486800a7024b..0524933856d4 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -541,18 +541,22 @@ static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
>         return container_of(mn, struct kvm, mmu_notifier);
>  }
>
> -typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
> +typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
>
>  typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
>                              unsigned long end);
>
>  typedef void (*on_unlock_fn_t)(struct kvm *kvm);
>
> -struct kvm_hva_range {
> -       unsigned long start;
> -       unsigned long end;
> +struct kvm_mmu_notifier_range {
> +       /*
> +        * 64-bit addresses, as KVM notifiers can operate on host virtual
> +        * addresses (unsigned long) and guest physical addresses (64-bit).
> +        */
> +       u64 start;
> +       u64 end;
>         union kvm_mmu_notifier_arg arg;
> -       hva_handler_t handler;
> +       gfn_handler_t handler;
>         on_lock_fn_t on_lock;
>         on_unlock_fn_t on_unlock;
>         bool flush_on_ret;
> @@ -581,7 +585,7 @@ static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG;
>              node = interval_tree_iter_next(node, start, last))      \
>
>  static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
> -                                                 const struct kvm_hva_range *range)
> +                                                 const struct kvm_mmu_notifier_range *range)
>  {
>         bool ret = false, locked = false;
>         struct kvm_gfn_range gfn_range;
> @@ -608,9 +612,9 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
>                         unsigned long hva_start, hva_end;
>
>                         slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
> -                       hva_start = max(range->start, slot->userspace_addr);
> -                       hva_end = min(range->end, slot->userspace_addr +
> -                                                 (slot->npages << PAGE_SHIFT));
> +                       hva_start = max_t(unsigned long, range->start, slot->userspace_addr);
> +                       hva_end = min_t(unsigned long, range->end,
> +                                       slot->userspace_addr + (slot->npages << PAGE_SHIFT));
>
>                         /*
>                          * To optimize for the likely case where the address
> @@ -660,10 +664,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
>                                                 unsigned long start,
>                                                 unsigned long end,
>                                                 union kvm_mmu_notifier_arg arg,
> -                                               hva_handler_t handler)
> +                                               gfn_handler_t handler)
>  {
>         struct kvm *kvm = mmu_notifier_to_kvm(mn);
> -       const struct kvm_hva_range range = {
> +       const struct kvm_mmu_notifier_range range = {
>                 .start          = start,
>                 .end            = end,
>                 .arg            = arg,
> @@ -680,10 +684,10 @@ static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
>  static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
>                                                          unsigned long start,
>                                                          unsigned long end,
> -                                                        hva_handler_t handler)
> +                                                        gfn_handler_t handler)
>  {
>         struct kvm *kvm = mmu_notifier_to_kvm(mn);
> -       const struct kvm_hva_range range = {
> +       const struct kvm_mmu_notifier_range range = {
>                 .start          = start,
>                 .end            = end,
>                 .handler        = handler,
> @@ -771,7 +775,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>                                         const struct mmu_notifier_range *range)
>  {
>         struct kvm *kvm = mmu_notifier_to_kvm(mn);
> -       const struct kvm_hva_range hva_range = {
> +       const struct kvm_mmu_notifier_range hva_range = {
>                 .start          = range->start,
>                 .end            = range->end,
>                 .handler        = kvm_unmap_gfn_range,
> @@ -835,7 +839,7 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
>                                         const struct mmu_notifier_range *range)
>  {
>         struct kvm *kvm = mmu_notifier_to_kvm(mn);
> -       const struct kvm_hva_range hva_range = {
> +       const struct kvm_mmu_notifier_range hva_range = {
>                 .start          = range->start,
>                 .end            = range->end,
>                 .handler        = (void *)kvm_null_fn,
> --
> 2.42.0.820.g83a721a137-goog
>