Re: [PATCH v3 10/13] nEPT: Nested INVEPT
On 05/19/2013 12:52 PM, Jun Nakajima wrote: > From: Nadav Har'El > > 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 Hmm? L0 can not always intercept L1's changes due to unsync shadow pages... > of this modification already calls INVEPT. Therefore, when L1 calls INVEPT, > we don't really need to do anything. In particular we *don't* need to call So, i can not understand why we need not handle INVEPT. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v3 10/13] nEPT: Nested INVEPT
Il 19/05/2013 06:52, Jun Nakajima ha scritto:
> + switch (type) {
> + case VMX_EPT_EXTENT_GLOBAL:
> + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_GLOBAL_BIT))
> + nested_vmx_failValid(vcpu,
> + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
> + else {
> + /*
> + * Do nothing: when L1 changes EPT12, we already
> + * update EPT02 (the shadow EPT table) and call INVEPT.
> + * So when L1 calls INVEPT, there's nothing left to do.
> + */
> + nested_vmx_succeed(vcpu);
> + }
> + break;
Duplicate code:
switch (type) {
case VMX_EPT_EXTENT_GLOBAL
ok = (nested_vmx_ept_caps & VMX_EPT_EXTENT_GLOBAL_BIT) != 0;
break;
...
default:
ok = false;
break;
}
if (ok) {
/* Do nothing: ... */
nested_vmx_succeed(vcpu);
} else {
nested_vmx_failValid(vcpu, ...);
}
break;
Paolo
> + case VMX_EPT_EXTENT_CONTEXT:
> + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_CONTEXT_BIT))
> + nested_vmx_failValid(vcpu,
> + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
> + else {
> + /* Do nothing */
> + nested_vmx_succeed(vcpu);
> + }
> + break;
> + case VMX_EPT_EXTENT_INDIVIDUAL_ADDR:
> + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_INDIVIDUAL_BIT))
> + nested_vmx_failValid(vcpu,
> + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
> + else {
> + /* Do nothing */
> + nested_vmx_succeed(vcpu);
> + }
> + break;
> + default:
> + nested_vmx_failValid(vcpu,
> + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
--
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[PATCH v3 10/13] nEPT: Nested INVEPT
From: Nadav Har'El
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. Therefore, when L1 calls INVEPT,
we don't really need to do anything. In particular we *don't* need to call
the real INVEPT again. All we do in our INVEPT is verify the validity of the
call, and its parameters, and then do nothing.
In KVM Forum 2010, Dong et al. presented "Nested Virtualization Friendly KVM"
and classified our current nested EPT implementation as "shadow-like virtual
EPT". He recommended instead a different approach, which he called "VTLB-like
virtual EPT". If we had taken that alternative approach, INVEPT would have had
a bigger role: L0 would only rebuild the shadow EPT table when L1 calls INVEPT.
Signed-off-by: Nadav Har'El
Signed-off-by: Jun Nakajima
Signed-off-by: Xinhao Xu
---
arch/x86/include/uapi/asm/vmx.h | 1 +
arch/x86/kvm/vmx.c | 83 +
2 files changed, 84 insertions(+)
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index d651082..7a34e8f 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_TIMER52
#define EXIT_REASON_WBINVD 54
#define EXIT_REASON_XSETBV 55
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1cf8a41..d9d991d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6251,6 +6251,87 @@ static int handle_vmptrst(struct kvm_vcpu *vcpu)
return 1;
}
+/* Emulate the INVEPT instruction */
+static int handle_invept(struct kvm_vcpu *vcpu)
+{
+ u32 vmx_instruction_info;
+ unsigned long type;
+ gva_t gva;
+ struct x86_exception e;
+ struct {
+ u64 eptp, gpa;
+ } operand;
+
+ 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;
+ }
+
+ /* According to the Intel VMX instruction reference, the memory
+* operand is read even if it isn't needed (e.g., for type==global)
+*/
+ vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ 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;
+ }
+
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);
+
+ switch (type) {
+ case VMX_EPT_EXTENT_GLOBAL:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_GLOBAL_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /*
+* Do nothing: when L1 changes EPT12, we already
+* update EPT02 (the shadow EPT table) and call INVEPT.
+* So when L1 calls INVEPT, there's nothing left to do.
+*/
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ case VMX_EPT_EXTENT_CONTEXT:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_CONTEXT_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /* Do nothing */
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ case VMX_EPT_EXTENT_INDIVIDUAL_ADDR:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_INDIVIDUAL_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /* Do nothing */
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ default:
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ }
+
+ skip_emulated_instruction(vcpu);
+ return 1;
+}
+
/*
* The exit handlers return 1 if the exit w
[PATCH v3 10/13] 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. Therefore, when L1 calls INVEPT,
we don't really need to do anything. In particular we *don't* need to call
the real INVEPT again. All we do in our INVEPT is verify the validity of the
call, and its parameters, and then do nothing.
In KVM Forum 2010, Dong et al. presented "Nested Virtualization Friendly KVM"
and classified our current nested EPT implementation as "shadow-like virtual
EPT". He recommended instead a different approach, which he called "VTLB-like
virtual EPT". If we had taken that alternative approach, INVEPT would have had
a bigger role: L0 would only rebuild the shadow EPT table when L1 calls INVEPT.
Signed-off-by: Nadav Har'El
Signed-off-by: Jun Nakajima
Signed-off-by: Xinhao Xu
---
arch/x86/include/uapi/asm/vmx.h | 1 +
arch/x86/kvm/vmx.c | 83 +
2 files changed, 84 insertions(+)
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index d651082..7a34e8f 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_TIMER52
#define EXIT_REASON_WBINVD 54
#define EXIT_REASON_XSETBV 55
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 136fc25..9ceab42 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6245,6 +6245,87 @@ static int handle_vmptrst(struct kvm_vcpu *vcpu)
return 1;
}
+/* Emulate the INVEPT instruction */
+static int handle_invept(struct kvm_vcpu *vcpu)
+{
+ u32 vmx_instruction_info;
+ unsigned long type;
+ gva_t gva;
+ struct x86_exception e;
+ struct {
+ u64 eptp, gpa;
+ } operand;
+
+ 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;
+ }
+
+ /* According to the Intel VMX instruction reference, the memory
+* operand is read even if it isn't needed (e.g., for type==global)
+*/
+ vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ 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;
+ }
+
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);
+
+ switch (type) {
+ case VMX_EPT_EXTENT_GLOBAL:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_GLOBAL_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /*
+* Do nothing: when L1 changes EPT12, we already
+* update EPT02 (the shadow EPT table) and call INVEPT.
+* So when L1 calls INVEPT, there's nothing left to do.
+*/
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ case VMX_EPT_EXTENT_CONTEXT:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_CONTEXT_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /* Do nothing */
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ case VMX_EPT_EXTENT_INDIVIDUAL_ADDR:
+ if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_INDIVIDUAL_BIT))
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ else {
+ /* Do nothing */
+ nested_vmx_succeed(vcpu);
+ }
+ break;
+ default:
+ nested_vmx_failValid(vcpu,
+ VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
+ }
+
+ skip_emulated_instruction(vcpu);
+ return 1;
+}
+
/*
* The exit handlers return 1 if the exit was handled fully and
