Messages in this thread | | | Subject | Re: [PATCH] KVM:X86 simply update A/D bits route | From | Paolo Bonzini <> | Date | Thu, 12 Oct 2017 16:18:47 +0200 |
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On 12/10/2017 23:17, Peng Hao wrote: > update_accessed_dirty_bits return 0 when dirty/accessed bits are > not supported. So walk_addr_generic just call update_accessed_dirty_bits > with supporting dirty/accessed bits. > > Signed-off-by: Peng Hao <peng.hao2@zte.com.cn> > --- > arch/x86/kvm/paging_tmpl.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h > index 86b68dc..b40f23e 100644 > --- a/arch/x86/kvm/paging_tmpl.h > +++ b/arch/x86/kvm/paging_tmpl.h > @@ -422,7 +422,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, > accessed_dirty &= pte >> > (PT_GUEST_DIRTY_SHIFT - PT_GUEST_ACCESSED_SHIFT); > > - if (unlikely(!accessed_dirty)) { > + if (unlikely(!accessed_dirty && have_ad)) { > ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, write_fault); > if (unlikely(ret < 0)) > goto error; >
At least you would have to remove the corresponding conditional in update_accessed_dirty_bits, or change it to a WARN.
But I don't see the point really... why is it _better_ to check in walk_addr_generic instead of update_accessed_dirty_bits?
Paolo
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