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Patch "kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)" has been added to the 4.8-stable tree

PATCH [email protected] 1 participant 1 message Jan 6, 2017

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This is a note to let you know that I've just added the patch titled

kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kvm-nvmx-allow-l1-to-intercept-software-exceptions-bp-and-of.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From ef85b67385436ddc1998f45f1d6a210f935b3388 Mon Sep 17 00:00:00 2001

From: Jim Mattson <[email protected]>
Date: Mon, 12 Dec 2016 11:01:37 -0800
Subject: kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)

From: Jim Mattson <[email protected]>

commit ef85b67385436ddc1998f45f1d6a210f935b3388 upstream.

When L2 exits to L0 due to "exception or NMI", software exceptions (#BP and #OF) for which L1 has requested an intercept should be handled by L1 rather than L0. Previously, only hardware exceptions were forwarded to L1.

Signed-off-by Jim Mattson <[email protected]>
Signed-off-by Paolo Bonzini <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/kvm/vmx.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)
arch/x86/kvm/vmx.c +5 -6
@@ -1336,10 +1336,10 @@ static inline bool nested_cpu_has_posted
 	return vmcs12->pin_based_vm_exec_control & PIN_BASED_POSTED_INTR;
 }
 
-static inline bool is_exception(u32 intr_info)
+static inline bool is_nmi(u32 intr_info)
 {
 	return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
-		== (INTR_TYPE_HARD_EXCEPTION | INTR_INFO_VALID_MASK);
+		== (INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK);
 }
 
 static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,

@@ -5467,7 +5467,7 @@ static int handle_exception(struct kvm_v
 	if (is_machine_check(intr_info))
 		return handle_machine_check(vcpu);
 
-	if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR)
+	if (is_nmi(intr_info))
 		return 1;  /* already handled by vmx_vcpu_run() */
 
 	if (is_no_device(intr_info)) {

@@ -7974,7 +7974,7 @@ static bool nested_vmx_exit_handled(stru
 
 	switch (exit_reason) {
 	case EXIT_REASON_EXCEPTION_NMI:
-		if (!is_exception(intr_info))
+		if (is_nmi(intr_info))
 			return false;
 		else if (is_page_fault(intr_info))
 			return enable_ept;

@@ -8572,8 +8572,7 @@ static void vmx_complete_atomic_exit(str
 		kvm_machine_check();
 
 	/* We need to handle NMIs before interrupts are enabled */
-	if ((exit_intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR &&
-	    (exit_intr_info & INTR_INFO_VALID_MASK)) {
+	if (is_nmi(exit_intr_info)) {
 		kvm_before_handle_nmi(&vmx->vcpu);
 		asm("int $2");
 		kvm_after_handle_nmi(&vmx->vcpu);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/kvm-nvmx-allow-l1-to-intercept-software-exceptions-bp-and-of.patch