Avi Kivity wrote:
> On 05/30/2010 03:36 PM, Xiao Guangrong wrote:
>> Introduce for_each_gfn_sp(), for_each_gfn_indirect_sp() and
>> for_each_gfn_indirect_valid_sp() to cleanup hlist traverseing
>>
>> Signed-off-by: Xiao Guangrong<xiaoguangrong@xxxxxxxxxxxxxx>
>> ---
>> arch/x86/kvm/mmu.c | 129
>> ++++++++++++++++++++++------------------------------
>> 1 files changed, 54 insertions(+), 75 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index 56f8c3c..84c705e 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -1200,6 +1200,22 @@ static void kvm_unlink_unsync_page(struct kvm
>> *kvm, struct kvm_mmu_page *sp)
>>
>> static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
>>
>> +#define for_each_gfn_sp(kvm, sp, gfn, pos, n) \
>> + hlist_for_each_entry_safe(sp, pos, n, \
>> + &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link)\
>> + if (sp->gfn == gfn)
>>
Avi,
Thanks for your review.
>
>
> if (...)
> for_each_gfn_sp(...)
> blah();
> else
> BUG();
>
> will break. Can do 'if ((sp)->gfn != (gfn)) ; else'.
>
> Or call functions from the for (;;) parameters to advance the cursor.
>
> (also use parentheses to protect macro arguments)
>
Yeah, it's my mistake, i'll fix it in the next version.
>
>
>> +
>> +#define for_each_gfn_indirect_sp(kvm, sp, gfn, pos, n) \
>> + hlist_for_each_entry_safe(sp, pos, n, \
>> + &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link)\
>> + if (sp->gfn == gfn&& !sp->role.direct)
>> +
>> +#define for_each_gfn_indirect_valid_sp(kvm, sp, gfn, pos, n) \
>> + hlist_for_each_entry_safe(sp, pos, n, \
>> + &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link)\
>> + if (sp->gfn == gfn&& !sp->role.direct&& \
>> + !sp->role.invalid)
>>
>
> Shouldn't we always skip invalid gfns?
Actually, in kvm_mmu_unprotect_page() function, it need find out
invalid shadow pages:
| hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
| if (sp->gfn == gfn && !sp->role.direct) {
| pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
| sp->role.word);
| r = 1;
| if (kvm_mmu_zap_page(kvm, sp))
| goto restart;
| }
I'm not sure whether we can skip invalid sp here, since it can change this
function's return value. :-(
> What about providing both gfn and role to the macro?
>
In current code, no code simply use role and gfn to find sp,
in kvm_mmu_get_page(), we need do other work for
'sp->gfn == gfn && sp->role != role' sp, and other functions only need compare
some members in role, but not all members.
Xiao
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