Re: [PATCH v18 11/18] RISC-V: KVM: Implement MMU notifiers

Dan Carpenter
2021-05-19T10:09:43Z

On Wed, May 19, 2021 at 09:05:46AM +0530, Anup Patel wrote:
> int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
> struct kvm_memory_slot *memslot,
> gpa_t gpa, unsigned long hva, bool is_write)
> @@ -569,7 +643,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
> struct kvm_mmu_page_cache *pcache = &vcpu->arch.mmu_page_cache;
> bool logging = (memslot->dirty_bitmap &&
> !(memslot->flags & KVM_MEM_READONLY)) ? true : false;
> - unsigned long vma_pagesize;
> + unsigned long vma_pagesize, mmu_seq;
>
> mmap_read_lock(current->mm);
>
> @@ -608,6 +682,8 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
> return ret;
> }
>
> + mmu_seq = kvm->mmu_notifier_seq;
> +
> hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable);
> if (hfn == KVM_PFN_ERR_HWPOISON) {
> send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva,
> @@ -626,6 +702,9 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
>
> spin_lock(&kvm->mmu_lock);
>
> + if (mmu_notifier_retry(kvm, mmu_seq))
> + goto out_unlock;

Do we need an error code here or is it a success path? You would
expect from the name that mmu_notifier_retry() would retry something
and return an error code, but it's actually a boolean function.

regards,
dan carpenter

> +
> if (writeable) {
> kvm_set_pfn_dirty(hfn);
> mark_page_dirty(kvm, gfn);
> @@ -639,6 +718,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
> if (ret)
> kvm_err("Failed to map in stage2\n");
>
> +out_unlock:
> spin_unlock(&kvm->mmu_lock);
> kvm_set_pfn_accessed(hfn);
> kvm_release_pfn_clean(hfn);