On Wed, Apr 01, 2020 at 08:50:56PM +0800, Zhuang Yanying wrote:
> From: LinFeng <linfeng23@xxxxxxxxxx>
>
> Just adding !is_zero_page() to kvm_is_reserved_pfn() is too
> rough. According to commit:e433e83bc3("KVM: MMU: Do not treat
> ZONE_DEVICE pages as being reserved"), special handling in some
> other flows is also need by zero_page, if not treat zero_page as
> being reserved.
>
> Signed-off-by: LinFeng <linfeng23@xxxxxxxxxx>
> Signed-off-by: Zhuang Yanying <ann.zhuangyanying@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 2 ++
> virt/kvm/kvm_main.c | 6 +++---
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 732c0270a489..e8db17d87c1a 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2961,6 +2961,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
> * here.
> */
> if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn) &&
> + !is_zero_pfn(pfn) &&
> level == PT_PAGE_TABLE_LEVEL &&
> PageTransCompoundMap(pfn_to_page(pfn)) &&
> !mmu_gfn_lpage_is_disallowed(vcpu, gfn, PT_DIRECTORY_LEVEL)) {
> @@ -5010,6 +5011,7 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
> */
> if (sp->role.direct &&
> !kvm_is_reserved_pfn(pfn) &&
> + !is_zero_pfn(pfn) &&
> PageTransCompoundMap(pfn_to_page(pfn))) {
> drop_spte(kvm, sptep);
> need_tlb_flush = 1;
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 7f7c22a687c0..fc0446bb393b 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1660,7 +1660,7 @@ static struct page *kvm_pfn_to_page(kvm_pfn_t pfn)
> if (is_error_noslot_pfn(pfn))
> return KVM_ERR_PTR_BAD_PAGE;
>
> - if (kvm_is_reserved_pfn(pfn)) {
> + if (kvm_is_reserved_pfn(pfn) && is_zero_pfn(pfn)) {
> WARN_ON(1);
> return KVM_ERR_PTR_BAD_PAGE;
> }
> @@ -1719,7 +1719,7 @@ static void kvm_release_pfn_dirty(kvm_pfn_t pfn)
>
> void kvm_set_pfn_dirty(kvm_pfn_t pfn)
> {
> - if (!kvm_is_reserved_pfn(pfn)) {
> + if (!kvm_is_reserved_pfn(pfn) && !is_zero_pfn(pfn)) {
> struct page *page = pfn_to_page(pfn);
>
> if (!PageReserved(page))
> @@ -1730,7 +1730,7 @@ EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
>
> void kvm_set_pfn_accessed(kvm_pfn_t pfn)
> {
> - if (!kvm_is_reserved_pfn(pfn))
> + if (!kvm_is_reserved_pfn(pfn) && !is_zero_pfn(pfn))
> mark_page_accessed(pfn_to_page(pfn));
> }
> EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
> --
> 2.23.0
>
>
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
