Re: [PATCH v2 1/3] RISC-V: KVM: Refactor kvm_arch_commit_memory_region()

[Anup Patel]

On Wed, Apr 29, 2026 at 3:05 PM <wang.yechao255@xxxxxxxxxx> wrote:
>
> From: Wang Yechao <wang.yechao255@xxxxxxxxxx>
>
> Refactor kvm_arch_commit_memory_region() as a preparation for a future
> commit to look cleaner and more understandable. Also, it looks more
> like its arm64 and x86 counterparts.

This claim of making it similar to arm64 and x86 is incorrect. See below.

>
> Signed-off-by: Wang Yechao <wang.yechao255@xxxxxxxxxx>
> ---
>  arch/riscv/kvm/mmu.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> index 2d3def024270..dc6a8efde99e 100644
> --- a/arch/riscv/kvm/mmu.c
> +++ b/arch/riscv/kvm/mmu.c
> @@ -141,12 +141,22 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
>                                 const struct kvm_memory_slot *new,
>                                 enum kvm_mr_change change)
>  {
> +       bool log_dirty_pages = new && new->flags & KVM_MEM_LOG_DIRTY_PAGES;
> +       bool read_only = new && new->flags & KVM_MEM_READONLY;
> +
> +       /*
> +        * Nothing more to do for RO slots (which can't be dirtied and can't be
> +        * made writable) or CREATE/MOVE/DELETE of a slot.
> +        */
> +       if ((change != KVM_MR_FLAGS_ONLY) || read_only)
> +               return;
> +

I don't see how this is same as what x86 and arm64 does. There is
no special casing for KVM_MR_FLAGS_ONLY in x86 and arm64.

>         /*
>          * At this point memslot has been committed and there is an
>          * allocated dirty_bitmap[], dirty pages will be tracked while
>          * the memory slot is write protected.
>          */
> -       if (change != KVM_MR_DELETE && new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
> +       if (log_dirty_pages) {

Why drop "change != KVM_MR_DELETE" ?

>                 if (kvm_dirty_log_manual_protect_and_init_set(kvm))
>                         return;
>                 mmu_wp_memory_region(kvm, new->id);
> --
> 2.43.5

Regards,
Anup