Re: [PATCH v4 5/5] KVM: MMU: introduce FNAME(prefetch_gpte)

Marcelo Tosatti
2012-10-10T16:29:06Z

On Sun, Oct 07, 2012 at 08:05:11PM +0800, Xiao Guangrong wrote:
> The only difference between FNAME(update_pte) and FNAME(pte_prefetch)
> is that the former is allowed to prefetch gfn from dirty logged slot,
> so introduce a common function to prefetch spte
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
> ---
> arch/x86/kvm/paging_tmpl.h | 55 +++++++++++++++++++------------------------
> 1 files changed, 24 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 36a80ed..f887e4c 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -305,31 +305,43 @@ static int FNAME(walk_addr_nested)(struct guest_walker *walker,
> addr, access);
> }
>
> -static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> - u64 *spte, const void *pte)
> +static bool
> +FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
> + u64 *spte, pt_element_t gpte, bool no_dirty_log)
> {
> - pt_element_t gpte;
> unsigned pte_access;
> + gfn_t gfn;
> pfn_t pfn;
>
> - gpte = *(const pt_element_t *)pte;
> if (prefetch_invalid_gpte(vcpu, sp, spte, gpte))
> - return;
> + return false;
>
> pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
> +
> + gfn = gpte_to_gfn(gpte);
> pte_access = sp->role.access & gpte_access(vcpu, gpte);
> protect_clean_gpte(&pte_access, gpte);
> - pfn = gfn_to_pfn_atomic(vcpu->kvm, gpte_to_gfn(gpte));
> + pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
> + no_dirty_log && (pte_access & ACC_WRITE_MASK));

Is this a bugfix?