From b7ebfb0509692cd923e31650f81ed4d79c9a3e59 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Fri, 25 Apr 2008 21:44:52 +0800 Subject: [PATCH] KVM: VMX: Prepare an identity page table for EPT in real mode [aliguory: plug leak] Signed-off-by: Sheng Yang Signed-off-by: Anthony Liguori Signed-off-by: Avi Kivity --- arch/x86/kvm/vmx.c | 79 ++++++++++++++++++++++++++++++++++++-- arch/x86/kvm/vmx.h | 3 ++ arch/x86/kvm/x86.c | 2 + include/asm-x86/kvm_host.h | 3 ++ 4 files changed, 84 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 98e4f2b036d..de5f6150f2f 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -87,7 +87,7 @@ static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu) return container_of(vcpu, struct vcpu_vmx, vcpu); } -static int init_rmode_tss(struct kvm *kvm); +static int init_rmode(struct kvm *kvm); static DEFINE_PER_CPU(struct vmcs *, vmxarea); static DEFINE_PER_CPU(struct vmcs *, current_vmcs); @@ -1304,7 +1304,7 @@ static void enter_rmode(struct kvm_vcpu *vcpu) fix_rmode_seg(VCPU_SREG_FS, &vcpu->arch.rmode.fs); kvm_mmu_reset_context(vcpu); - init_rmode_tss(vcpu->kvm); + init_rmode(vcpu->kvm); } #ifdef CONFIG_X86_64 @@ -1578,6 +1578,41 @@ out: return ret; } +static int init_rmode_identity_map(struct kvm *kvm) +{ + int i, r, ret; + pfn_t identity_map_pfn; + u32 tmp; + + if (!vm_need_ept()) + return 1; + if (unlikely(!kvm->arch.ept_identity_pagetable)) { + printk(KERN_ERR "EPT: identity-mapping pagetable " + "haven't been allocated!\n"); + return 0; + } + if (likely(kvm->arch.ept_identity_pagetable_done)) + return 1; + ret = 0; + identity_map_pfn = VMX_EPT_IDENTITY_PAGETABLE_ADDR >> PAGE_SHIFT; + r = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE); + if (r < 0) + goto out; + /* Set up identity-mapping pagetable for EPT in real mode */ + for (i = 0; i < PT32_ENT_PER_PAGE; i++) { + tmp = (i << 22) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | + _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE); + r = kvm_write_guest_page(kvm, identity_map_pfn, + &tmp, i * sizeof(tmp), sizeof(tmp)); + if (r < 0) + goto out; + } + kvm->arch.ept_identity_pagetable_done = true; + ret = 1; +out: + return ret; +} + static void seg_setup(int seg) { struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg]; @@ -1612,6 +1647,31 @@ out: return r; } +static int alloc_identity_pagetable(struct kvm *kvm) +{ + struct kvm_userspace_memory_region kvm_userspace_mem; + int r = 0; + + down_write(&kvm->slots_lock); + if (kvm->arch.ept_identity_pagetable) + goto out; + kvm_userspace_mem.slot = IDENTITY_PAGETABLE_PRIVATE_MEMSLOT; + kvm_userspace_mem.flags = 0; + kvm_userspace_mem.guest_phys_addr = VMX_EPT_IDENTITY_PAGETABLE_ADDR; + kvm_userspace_mem.memory_size = PAGE_SIZE; + r = __kvm_set_memory_region(kvm, &kvm_userspace_mem, 0); + if (r) + goto out; + + down_read(¤t->mm->mmap_sem); + kvm->arch.ept_identity_pagetable = gfn_to_page(kvm, + VMX_EPT_IDENTITY_PAGETABLE_ADDR >> PAGE_SHIFT); + up_read(¤t->mm->mmap_sem); +out: + up_write(&kvm->slots_lock); + return r; +} + static void allocate_vpid(struct vcpu_vmx *vmx) { int vpid; @@ -1775,6 +1835,15 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) return 0; } +static int init_rmode(struct kvm *kvm) +{ + if (!init_rmode_tss(kvm)) + return 0; + if (!init_rmode_identity_map(kvm)) + return 0; + return 1; +} + static int vmx_vcpu_reset(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -1782,7 +1851,7 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu) int ret; down_read(&vcpu->kvm->slots_lock); - if (!init_rmode_tss(vmx->vcpu.kvm)) { + if (!init_rmode(vmx->vcpu.kvm)) { ret = -ENOMEM; goto out; } @@ -2759,6 +2828,10 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) if (alloc_apic_access_page(kvm) != 0) goto free_vmcs; + if (vm_need_ept()) + if (alloc_identity_pagetable(kvm) != 0) + goto free_vmcs; + return &vmx->vcpu; free_vmcs: diff --git a/arch/x86/kvm/vmx.h b/arch/x86/kvm/vmx.h index 093b085daf6..f97eccc754e 100644 --- a/arch/x86/kvm/vmx.h +++ b/arch/x86/kvm/vmx.h @@ -340,6 +340,7 @@ enum vmcs_field { #define MSR_IA32_FEATURE_CONTROL_VMXON_ENABLED 0x4 #define APIC_ACCESS_PAGE_PRIVATE_MEMSLOT 9 +#define IDENTITY_PAGETABLE_PRIVATE_MEMSLOT 10 #define VMX_NR_VPIDS (1 << 16) #define VMX_VPID_EXTENT_SINGLE_CONTEXT 1 @@ -353,4 +354,6 @@ enum vmcs_field { #define VMX_EPT_EXTENT_GLOBAL_BIT (1ull << 26) #define VMX_EPT_DEFAULT_GAW 3 +#define VMX_EPT_IDENTITY_PAGETABLE_ADDR 0xfffbc000ul + #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0735efbfa71..1842a86f7c3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3909,6 +3909,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm) kvm_free_physmem(kvm); if (kvm->arch.apic_access_page) put_page(kvm->arch.apic_access_page); + if (kvm->arch.ept_identity_pagetable) + put_page(kvm->arch.ept_identity_pagetable); kfree(kvm); } diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h index d1dedda958f..e24afaa64a4 100644 --- a/include/asm-x86/kvm_host.h +++ b/include/asm-x86/kvm_host.h @@ -314,6 +314,9 @@ struct kvm_arch{ struct page *apic_access_page; gpa_t wall_clock; + + struct page *ept_identity_pagetable; + bool ept_identity_pagetable_done; }; struct kvm_vm_stat { -- 2.41.1