From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> In some case, special roots are used in mmu. It is often using to_shadow_page(mmu->root.hpa) to check if special roots are used. Add using_special_root_page() to directly check if special roots are used or needed to be used even mmu->root.hpa is not set. Prepare for making to_shadow_page(mmu->root.hpa) return non-NULL via using special shadow pages. Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> --- arch/x86/kvm/mmu/mmu.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 909372762363..7f20796af351 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1711,6 +1711,14 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } +static bool using_special_root_page(struct kvm_mmu *mmu) +{ + if (mmu->root_role.direct) + return mmu->root_role.level == PT32E_ROOT_LEVEL; + else + return mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL; +} + static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct) { struct kvm_mmu_page *sp; @@ -4241,10 +4249,10 @@ static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu, { /* * For now, limit the caching to 64-bit hosts+VMs in order to avoid - * having to deal with PDPTEs. We may add support for 32-bit hosts/VMs - * later if necessary. + * having to deal with PDPTEs. Special roots can not be put into + * mmu->prev_roots[]. */ - if (VALID_PAGE(mmu->root.hpa) && !to_shadow_page(mmu->root.hpa)) + if (VALID_PAGE(mmu->root.hpa) && using_special_root_page(mmu)) kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT); if (VALID_PAGE(mmu->root.hpa)) -- 2.19.1.6.gb485710b