On Fri, Mar 29, 2013 at 02:05:26PM +0900, Takuya Yoshikawa wrote:
> With the following commit, shadow pages can be zapped at random during
> a shadow page talbe walk:
> KVM: MMU: Move kvm_mmu_free_some_pages() into kvm_mmu_alloc_page()
> 7ddca7e43c8f28f9419da81a0e7730b66aa60fe9
>
> This patch reverts it and fixes __direct_map() and FNAME(fetch)().
>
> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
Applied, thanks.
> ---
> arch/x86/kvm/mmu.c | 11 +++++++----
> arch/x86/kvm/paging_tmpl.h | 1 +
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 633e30c..004cc87 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1501,15 +1501,11 @@ static void drop_parent_pte(struct kvm_mmu_page *sp,
> mmu_spte_clear_no_track(parent_pte);
> }
>
> -static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
> -
> static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
> u64 *parent_pte, int direct)
> {
> struct kvm_mmu_page *sp;
>
> - make_mmu_pages_available(vcpu);
> -
> sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
> sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> if (!direct)
> @@ -2806,6 +2802,7 @@ exit:
>
> static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
> gva_t gva, pfn_t *pfn, bool write, bool *writable);
> +static void make_mmu_pages_available(struct kvm_vcpu *vcpu);
>
> static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
> gfn_t gfn, bool prefault)
> @@ -2847,6 +2844,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
> spin_lock(&vcpu->kvm->mmu_lock);
> if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
> goto out_unlock;
> + make_mmu_pages_available(vcpu);
> if (likely(!force_pt_level))
> transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
> r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
> @@ -2924,6 +2922,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
>
> if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
> spin_lock(&vcpu->kvm->mmu_lock);
> + make_mmu_pages_available(vcpu);
> sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
> 1, ACC_ALL, NULL);
> ++sp->root_count;
> @@ -2935,6 +2934,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
>
> ASSERT(!VALID_PAGE(root));
> spin_lock(&vcpu->kvm->mmu_lock);
> + make_mmu_pages_available(vcpu);
> sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT),
> i << 30,
> PT32_ROOT_LEVEL, 1, ACC_ALL,
> @@ -2973,6 +2973,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
> ASSERT(!VALID_PAGE(root));
>
> spin_lock(&vcpu->kvm->mmu_lock);
> + make_mmu_pages_available(vcpu);
> sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
> 0, ACC_ALL, NULL);
> root = __pa(sp->spt);
> @@ -3006,6 +3007,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
> return 1;
> }
> spin_lock(&vcpu->kvm->mmu_lock);
> + make_mmu_pages_available(vcpu);
> sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
> PT32_ROOT_LEVEL, 0,
> ACC_ALL, NULL);
> @@ -3311,6 +3313,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
> spin_lock(&vcpu->kvm->mmu_lock);
> if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
> goto out_unlock;
> + make_mmu_pages_available(vcpu);
> if (likely(!force_pt_level))
> transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
> r = __direct_map(vcpu, gpa, write, map_writable,
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index af143f0..da20860 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -627,6 +627,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
> goto out_unlock;
>
> kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
> + make_mmu_pages_available(vcpu);
> if (!force_pt_level)
> transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
> r = FNAME(fetch)(vcpu, addr, &walker, write_fault,
> --
> 1.7.5.4
--
Gleb.
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