nEPT: Nested INVEPT
If we let L1 use EPT, we should probably also support the INVEPT instruction.
In our current nested EPT implementation, when L1 changes its EPT table
for L2 (i.e., EPT12), L0 modifies the shadow EPT table (EPT02), and in
the course of this modification already calls INVEPT. But if last level
of shadow page is unsync not all L1's changes to EPT12 are intercepted,
which means roots need to be synced when L1 calls INVEPT. Global INVEPT
should not be different since roots are synced by kvm_mmu_load() each
time EPTP02 changes.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
Signed-off-by: Xinhao Xu <xinhao.xu@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index f3e01a2..966502d 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -387,6 +387,7 @@
#define VMX_EPT_EXTENT_INDIVIDUAL_ADDR 0
#define VMX_EPT_EXTENT_CONTEXT 1
#define VMX_EPT_EXTENT_GLOBAL 2
+#define VMX_EPT_EXTENT_SHIFT 24
#define VMX_EPT_EXECUTE_ONLY_BIT (1ull)
#define VMX_EPT_PAGE_WALK_4_BIT (1ull << 6)
@@ -394,6 +395,7 @@
#define VMX_EPTP_WB_BIT (1ull << 14)
#define VMX_EPT_2MB_PAGE_BIT (1ull << 16)
#define VMX_EPT_1GB_PAGE_BIT (1ull << 17)
+#define VMX_EPT_INVEPT_BIT (1ull << 20)
#define VMX_EPT_AD_BIT (1ull << 21)
#define VMX_EPT_EXTENT_CONTEXT_BIT (1ull << 25)
#define VMX_EPT_EXTENT_GLOBAL_BIT (1ull << 26)
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index d651082..7a34e8fe 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -65,6 +65,7 @@
#define EXIT_REASON_EOI_INDUCED 45
#define EXIT_REASON_EPT_VIOLATION 48
#define EXIT_REASON_EPT_MISCONFIG 49
+#define EXIT_REASON_INVEPT 50
#define EXIT_REASON_PREEMPTION_TIMER 52
#define EXIT_REASON_WBINVD 54
#define EXIT_REASON_XSETBV 55
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 992fde9..9651c99 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3182,6 +3182,7 @@
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
}
+EXPORT_SYMBOL_GPL(kvm_mmu_sync_roots);
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
u32 access, struct x86_exception *exception)
@@ -3451,6 +3452,7 @@
++vcpu->stat.tlb_flush;
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
}
+EXPORT_SYMBOL_GPL(kvm_mmu_flush_tlb);
static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2ae0aa4..5129ba3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -712,6 +712,7 @@
kvm_release_page_clean(page);
}
+static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu);
static u64 construct_eptp(unsigned long root_hpa);
static void kvm_cpu_vmxon(u64 addr);
static void kvm_cpu_vmxoff(void);
@@ -2161,6 +2162,7 @@
static u32 nested_vmx_exit_ctls_low, nested_vmx_exit_ctls_high;
static u32 nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high;
static u32 nested_vmx_misc_low, nested_vmx_misc_high;
+static u32 nested_vmx_ept_caps;
static __init void nested_vmx_setup_ctls_msrs(void)
{
/*
@@ -6279,6 +6281,74 @@
return 1;
}
+/* Emulate the INVEPT instruction */
+static int handle_invept(struct kvm_vcpu *vcpu)
+{
+ u32 vmx_instruction_info, types;
+ unsigned long type;
+ gva_t gva;
+ struct x86_exception e;
+ struct {
+ u64 eptp, gpa;
+ } operand;
+ u64 eptp_mask = ((1ull << 51) - 1) & PAGE_MASK;
+
+ if (!(nested_vmx_secondary_ctls_high & SECONDARY_EXEC_ENABLE_EPT) ||
+ !(nested_vmx_ept_caps & VMX_EPT_INVEPT_BIT)) {
+ kvm_queue_exception(vcpu, UD_VECTOR);
+ return 1;
+ }
+
+ if (!nested_vmx_check_permission(vcpu))
+ return 1;
+
+ if (!kvm_read_cr0_bits(vcpu, X86_CR0_PE)) {
+ kvm_queue_exception(vcpu, UD_VECTOR);
+ return 1;
+ }
+
+ vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);
+
+ types = (nested_vmx_ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;
+
+ if (!(types & (1UL << type))) {
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ return 1;
+ }
+
+ /* According to the Intel VMX instruction reference, the memory
+ * operand is read even if it isn't needed (e.g., for type==global)
+ */
+ if (get_vmx_mem_address(vcpu, vmcs_readl(EXIT_QUALIFICATION),
+ vmx_instruction_info, &gva))
+ return 1;
+ if (kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, gva, &operand,
+ sizeof(operand), &e)) {
+ kvm_inject_page_fault(vcpu, &e);
+ return 1;
+ }
+
+ switch (type) {
+ case VMX_EPT_EXTENT_CONTEXT:
+ if ((operand.eptp & eptp_mask) !=
+ (nested_ept_get_cr3(vcpu) & eptp_mask))
+ break;
+ case VMX_EPT_EXTENT_GLOBAL:
+ kvm_mmu_sync_roots(vcpu);
+ kvm_mmu_flush_tlb(vcpu);
+ nested_vmx_succeed(vcpu);
+ break;
+ default:
+ BUG_ON(1);
+ break;
+ }
+
+ skip_emulated_instruction(vcpu);
+ return 1;
+}
+
/*
* The exit handlers return 1 if the exit was handled fully and guest execution
* may resume. Otherwise they set the kvm_run parameter to indicate what needs
@@ -6323,6 +6393,7 @@
[EXIT_REASON_PAUSE_INSTRUCTION] = handle_pause,
[EXIT_REASON_MWAIT_INSTRUCTION] = handle_invalid_op,
[EXIT_REASON_MONITOR_INSTRUCTION] = handle_invalid_op,
+ [EXIT_REASON_INVEPT] = handle_invept,
};
static const int kvm_vmx_max_exit_handlers =
@@ -6549,6 +6620,7 @@
case EXIT_REASON_VMPTRST: case EXIT_REASON_VMREAD:
case EXIT_REASON_VMRESUME: case EXIT_REASON_VMWRITE:
case EXIT_REASON_VMOFF: case EXIT_REASON_VMON:
+ case EXIT_REASON_INVEPT:
/*
* VMX instructions trap unconditionally. This allows L1 to
* emulate them for its L2 guest, i.e., allows 3-level nesting!