Messages in this thread | | | Subject | Re: [PATCH 07/10] KVM: x86: MMU: Encapsulate the type of rmap-chain head in a new struct | From | Takuya Yoshikawa <> | Date | Thu, 19 Nov 2015 11:23:58 +0900 |
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On 2015/11/18 18:09, Paolo Bonzini wrote:
> On 18/11/2015 04:21, Xiao Guangrong wrote:
>> On 11/12/2015 07:55 PM, Takuya Yoshikawa wrote: >>> @@ -1720,7 +1724,7 @@ static struct kvm_mmu_page >>> *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, >>> * this feature. See the comments in kvm_zap_obsolete_pages(). >>> */ >>> list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); >>> - sp->parent_ptes = 0; >>> + sp->parent_ptes.val = 0; >> >> The sp is allocated from kmem_cache_zalloc() so explicitly initialize it >> to zero is not needed. > > Right, but it should be a separate patch. > > Takuya, since you are going to send another version of this series, can > you also:
Yes, I'm preparing to do so.
> 1) move this patch either to the beginning or to the end > > 2) include "KVM: x86: always set accessed bit in shadow PTEs", also near > the beginning of the series?
Commit 1c9a5e19b1af8a2c ("KVM: x86: MMU: always set accessed bit in shadow PTEs") will be the first.
Then, the ordering will become something like this:
02: Encapsulate the type of rmap-chain head in a new struct 03: Remove unused parameter of __direct_map() 04: Add helper function to clear a bit in unsync child bitmap 05: Make mmu_set_spte() return emulate value 06: Remove is_rmap_spte() and use is_shadow_present_pte()
These five seem to be easy ones for you to apply: since patch 02 touches many places, it should go first to become the base of the following work.
07: Consolidate BUG_ON checks for reverse-mapped sptes
I will change the WARN_ON to BUG_ON. // Marcelo's comment
08: Move initialization of parent_ptes out from kvm_mmu_alloc_page()
In this patch, I will delete "sp->parent_ptes.val = 0;" line since this is the problem of kvm_mmu_alloc_page(), though not a new one. // Xiao's comment
09: Use for_each_rmap_spte macro instead of pte_list_walk()
There is some confusion between us: Paolo and I agreed that the patch keeps the original way and calls mark_unsync() the same way as before, but there are still comments from Marcelo and Xiao and those comments seem to explain the code differently.
I will check again, but I may not change this one and the following two patches in the next version. If we can eliminate some of the mark_unsync() calls, that will be kind of an optimization which this series does not intend to achieve.
Anyway, by moving the non-trivial two patches (09 and 10) here, reviewing will become easier and you can apply the other patches separately.
10: Move parent_pte handling from kvm_mmu_get_page() to link_shadow_page() 11: Remove unused parameter parent_pte from kvm_mmu_get_page()
Thanks, Takuya
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