From 1ad9f23873a4ee837643be5a29c05e405ec54e18 Mon Sep 17 00:00:00 2001 From: "pingfank@linux.vnet.ibm.com" Date: Tue, 15 Apr 2014 16:33:40 +0800 Subject: [PATCH] KVM: PPC: Book3S: HV: make _PAGE_NUMA take effect Numa fault is a method which help to achieve auto numa balancing. When such a page fault takes place, the page fault handler will check whether the page is placed correctly. If not, migration should be involved to cut down the distance between the cpu and pages. A pte with _PAGE_NUMA help to implement numa fault. It means not to allow the MMU to access the page directly. So a page fault is triggered and numa fault handler gets the opportunity to run checker. As for the access of MMU, we need special handling for the powernv's guest. When we mark a pte with _PAGE_NUMA, we already call mmu_notifier to invalidate it in guest's htab, but when we tried to re-insert them, we firstly try to map it in real-mode. Only after this fails, we fallback to virt mode, and most of important, we run numa fault handler in virt mode. This patch guards the way of real-mode to ensure that if a pte is marked with _PAGE_NUMA, it will NOT be mapped in real mode, instead, it will be mapped in virt mode and have the opportunity to be checked with placement. Signed-off-by: Liu Ping Fan Reviewed-by: Aneesh Kumar K.V Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_hv_rm_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c index 1d6c56ad5b60..8fcc36306a02 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c @@ -234,7 +234,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags, pte_size = psize; pte = lookup_linux_pte_and_update(pgdir, hva, writing, &pte_size); - if (pte_present(pte)) { + if (pte_present(pte) && !pte_numa(pte)) { if (writing && !pte_write(pte)) /* make the actual HPTE be read-only */ ptel = hpte_make_readonly(ptel); -- GitLab