Hi Gavin,
On 2021/3/15 12:18, Gavin Shan wrote:
> We needn't retrieve the memory slot again in user_mem_abort() because
> the corresponding memory slot has been passed from the caller. This
I think you are right, though fault_ipa will be adjusted when we try to use
block mapping,
the fault_supports_stage2_huge_mapping() makes sure we're not trying to map
anything
not covered by the memslot, so the adjusted fault_ipa still belongs to the
memslot.
> would save some CPU cycles. For example, the time used to write 1GB
> memory, which is backed by 2MB hugetlb pages and write-protected, is
> dropped by 6.8% from 928ms to 864ms.
>
> Signed-off-by: Gavin Shan <gs...@redhat.com>
> ---
> arch/arm64/kvm/mmu.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index a5a8ade9fde4..4a4abcccfafb 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -846,7 +846,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu,
> phys_addr_t fault_ipa,
> */
> smp_rmb();
>
> - pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writable);
> + pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
> + write_fault, &writable, NULL);
It's better to update the code comments at same time.
> if (pfn == KVM_PFN_ERR_HWPOISON) {
> kvm_send_hwpoison_signal(hva, vma_shift);
> return 0;
> @@ -912,7 +913,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu,
> phys_addr_t fault_ipa,
> /* Mark the page dirty only if the fault is handled successfully */
> if (writable && !ret) {
> kvm_set_pfn_dirty(pfn);
> - mark_page_dirty(kvm, gfn);
> + mark_page_dirty_in_slot(kvm, memslot, gfn);
> }
>
> out_unlock:
>
Thanks,
Keqian.
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