Re: [PATCH v12 56/84] KVM: RISC-V: Mark "struct page" pfns dirty iff a stage-2 PTE is installed

Anup Patel
2024-08-06T15:05:17Z

On Sat, Jul 27, 2024 at 5:24 AM Sean Christopherson <seanjc@google.com> wrote:
>
> Don't mark pages dirty if KVM bails from the page fault handler without
> installing a stage-2 mapping, i.e. if the page is guaranteed to not be
> written by the guest.
>
> In addition to being a (very) minor fix, this paves the way for converting
> RISC-V to use kvm_release_faultin_page().
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

For KVM RISC-V:
Acked-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
> arch/riscv/kvm/mmu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> index b63650f9b966..06aa5a0d056d 100644
> --- a/arch/riscv/kvm/mmu.c
> +++ b/arch/riscv/kvm/mmu.c
> @@ -669,7 +669,6 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
> goto out_unlock;
>
> if (writable) {
> - kvm_set_pfn_dirty(hfn);
> mark_page_dirty(kvm, gfn);
> ret = gstage_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
> vma_pagesize, false, true);
> @@ -682,6 +681,9 @@ int kvm_riscv_gstage_map(struct kvm_vcpu *vcpu,
> kvm_err("Failed to map in G-stage\n");
>
> out_unlock:
> + if ((!ret || ret == -EEXIST) && writable)
> + kvm_set_pfn_dirty(hfn);
> +
> spin_unlock(&kvm->mmu_lock);
> kvm_set_pfn_accessed(hfn);
> kvm_release_pfn_clean(hfn);
> --
> 2.46.0.rc1.232.g9752f9e123-goog
>