linux-kernel - [PATCH 3.10 19/24] nEPT: Nested INVEPT

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Date:	Sun, 14 Dec 2014 12:20:39 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>,
	Nadav HarEl <nyh@...ibm.com>,
	Jun Nakajima <jun.nakajima@...el.com>,
	Xinhao Xu <xinhao.xu@...el.com>,
	Yang Zhang <yang.z.zhang@...el.com>,
	Gleb Natapov <gleb@...hat.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Ben Hutchings <ben@...adent.org.uk>,
	Vinson Lee <vlee@...pensource.com>
Subject: [PATCH 3.10 19/24] nEPT: Nested INVEPT

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nadav Har'El <nyh@...ibm.com>

commit bfd0a56b90005f8c8a004baf407ad90045c2b11e upstream.

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@...ux.vnet.ibm.com>
Signed-off-by: Nadav Har'El <nyh@...ibm.com>
Signed-off-by: Jun Nakajima <jun.nakajima@...el.com>
Signed-off-by: Xinhao Xu <xinhao.xu@...el.com>
Signed-off-by: Yang Zhang <yang.z.zhang@...el.com>
Signed-off-by: Gleb Natapov <gleb@...hat.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
[bwh: Backported to 3.2:
 - Adjust context, filename
 - Simplify handle_invept() as recommended by Paolo - nEPT is not
   supported so we always raise #UD]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Cc: Vinson Lee <vlee@...pensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/include/uapi/asm/vmx.h |    1 +
 arch/x86/kvm/vmx.c              |    8 ++++++++
 2 files changed, 9 insertions(+)

--- 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
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6242,6 +6242,12 @@ static int handle_vmptrst(struct kvm_vcp
 	return 1;
 }
 
+static int handle_invept(struct kvm_vcpu *vcpu)
+{
+	kvm_queue_exception(vcpu, UD_VECTOR);
+	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
@@ -6286,6 +6292,7 @@ static int (*const kvm_vmx_exit_handlers
 	[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 =
@@ -6512,6 +6519,7 @@ static bool nested_vmx_exit_handled(stru
 	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!


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