From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> mmu->pae_root for non-PAE paging is allocated on-demand, but mmu->pae_root for PAE paging is allocated early when struct kvm_mmu is being created. Simplify the code to allocate mmu->pae_root for PAE paging and make it on-demand. Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/mmu/mmu.c | 101 +++++++++++++------------------- arch/x86/kvm/x86.c | 4 +- 3 files changed, 44 insertions(+), 63 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9cdc5bbd721f..fb9751dfc1a7 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1615,7 +1615,7 @@ int kvm_mmu_vendor_module_init(void); void kvm_mmu_vendor_module_exit(void); void kvm_mmu_destroy(struct kvm_vcpu *vcpu); -int kvm_mmu_create(struct kvm_vcpu *vcpu); +void kvm_mmu_create(struct kvm_vcpu *vcpu); int kvm_mmu_init_vm(struct kvm *kvm); void kvm_mmu_uninit_vm(struct kvm *kvm); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 90b715eefe6a..63c2b2c6122c 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -668,6 +668,41 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu) } } +static int mmu_alloc_pae_root(struct kvm_vcpu *vcpu) +{ + struct page *page; + + if (vcpu->arch.mmu->root_role.level != PT32E_ROOT_LEVEL) + return 0; + if (vcpu->arch.mmu->pae_root) + return 0; + + /* + * Allocate a page to hold the four PDPTEs for PAE paging when emulating + * 32-bit mode. CR3 is only 32 bits even on x86_64 in this case. + * Therefore we need to allocate the PDP table in the first 4GB of + * memory, which happens to fit the DMA32 zone. + */ + page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_DMA32); + if (!page) + return -ENOMEM; + vcpu->arch.mmu->pae_root = page_address(page); + + /* + * CR3 is only 32 bits when PAE paging is used, thus it's impossible to + * get the CPU to treat the PDPTEs as encrypted. Decrypt the page so + * that KVM's writes and the CPU's reads get along. Note, this is + * only necessary when using shadow paging, as 64-bit NPT can get at + * the C-bit even when shadowing 32-bit NPT, and SME isn't supported + * by 32-bit kernels (when KVM itself uses 32-bit NPT). + */ + if (!tdp_enabled) + set_memory_decrypted((unsigned long)vcpu->arch.mmu->pae_root, 1); + else + WARN_ON_ONCE(shadow_me_value); + return 0; +} + static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect) { int r; @@ -5127,6 +5162,9 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu) r = mmu_topup_memory_caches(vcpu, !vcpu->arch.mmu->root_role.direct); if (r) goto out; + r = mmu_alloc_pae_root(vcpu); + if (r) + return r; r = mmu_alloc_special_roots(vcpu); if (r) goto out; @@ -5591,63 +5629,18 @@ static void free_mmu_pages(struct kvm_mmu *mmu) free_page((unsigned long)mmu->pml5_root); } -static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) +static void __kvm_mmu_create(struct kvm_mmu *mmu) { - struct page *page; int i; mmu->root.hpa = INVALID_PAGE; mmu->root.pgd = 0; for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID; - - /* vcpu->arch.guest_mmu isn't used when !tdp_enabled. */ - if (!tdp_enabled && mmu == &vcpu->arch.guest_mmu) - return 0; - - /* - * When using PAE paging, the four PDPTEs are treated as 'root' pages, - * while the PDP table is a per-vCPU construct that's allocated at MMU - * creation. When emulating 32-bit mode, cr3 is only 32 bits even on - * x86_64. Therefore we need to allocate the PDP table in the first - * 4GB of memory, which happens to fit the DMA32 zone. TDP paging - * generally doesn't use PAE paging and can skip allocating the PDP - * table. The main exception, handled here, is SVM's 32-bit NPT. The - * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit - * KVM; that horror is handled on-demand by mmu_alloc_special_roots(). - */ - if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) - return 0; - - page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_DMA32); - if (!page) - return -ENOMEM; - - mmu->pae_root = page_address(page); - - /* - * CR3 is only 32 bits when PAE paging is used, thus it's impossible to - * get the CPU to treat the PDPTEs as encrypted. Decrypt the page so - * that KVM's writes and the CPU's reads get along. Note, this is - * only necessary when using shadow paging, as 64-bit NPT can get at - * the C-bit even when shadowing 32-bit NPT, and SME isn't supported - * by 32-bit kernels (when KVM itself uses 32-bit NPT). - */ - if (!tdp_enabled) - set_memory_decrypted((unsigned long)mmu->pae_root, 1); - else - WARN_ON_ONCE(shadow_me_value); - - for (i = 0; i < 4; ++i) - mmu->pae_root[i] = INVALID_PAE_ROOT; - - return 0; } -int kvm_mmu_create(struct kvm_vcpu *vcpu) +void kvm_mmu_create(struct kvm_vcpu *vcpu) { - int ret; - vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache; vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO; @@ -5659,18 +5652,8 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; - ret = __kvm_mmu_create(vcpu, &vcpu->arch.guest_mmu); - if (ret) - return ret; - - ret = __kvm_mmu_create(vcpu, &vcpu->arch.root_mmu); - if (ret) - goto fail_allocate_root; - - return ret; - fail_allocate_root: - free_mmu_pages(&vcpu->arch.guest_mmu); - return ret; + __kvm_mmu_create(&vcpu->arch.guest_mmu); + __kvm_mmu_create(&vcpu->arch.root_mmu); } #define BATCH_ZAP_PAGES 10 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 04812eaaf61b..064aecb188dc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11285,9 +11285,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) else vcpu->arch.mp_state = KVM_MP_STATE_UNINITIALIZED; - r = kvm_mmu_create(vcpu); - if (r < 0) - return r; + kvm_mmu_create(vcpu); if (irqchip_in_kernel(vcpu->kvm)) { r = kvm_create_lapic(vcpu, lapic_timer_advance_ns); -- 2.19.1.6.gb485710b