Patch "KVM: nVMX: Fix vmx_check_nested_events() return value in case an event was reinjected to L2" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

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

    KVM: nVMX: Fix vmx_check_nested_events() return value in case an event was reinjected to L2

to the 4.14-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-fix-vmx_check_nested_events-return-value-in-case-an-event-was-reinjected-to-l2.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Feb  1 13:45:42 CET 2018
From: Liran Alon <liran.alon@oracle.com>
Date: Sun, 5 Nov 2017 16:07:43 +0200
Subject: KVM: nVMX: Fix vmx_check_nested_events() return value in case an event was reinjected to L2

From: Liran Alon <liran.alon@oracle.com>


[ Upstream commit 917dc6068bc12a2dafffcf0e9d405ddb1b8780cb ]

vmx_check_nested_events() should return -EBUSY only in case there is a
pending L1 event which requires a VMExit from L2 to L1 but such a
VMExit is currently blocked. Such VMExits are blocked either
because nested_run_pending=1 or an event was reinjected to L2.
vmx_check_nested_events() should return 0 in case there are no
pending L1 events which requires a VMExit from L2 to L1 or if
a VMExit from L2 to L1 was done internally.

However, upstream commit which introduced blocking in case an event was
reinjected to L2 (commit acc9ab601327 ("KVM: nVMX: Fix pending events
injection")) contains a bug: It returns -EBUSY even if there are no
pending L1 events which requires VMExit from L2 to L1.

This commit fix this issue.

Fixes: acc9ab601327 ("KVM: nVMX: Fix pending events injection")

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/vmx.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11114,13 +11114,12 @@ static int vmx_check_nested_events(struc
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	unsigned long exit_qual;
-
-	if (kvm_event_needs_reinjection(vcpu))
-		return -EBUSY;
+	bool block_nested_events =
+	    vmx->nested.nested_run_pending || kvm_event_needs_reinjection(vcpu);
 
 	if (vcpu->arch.exception.pending &&
 		nested_vmx_check_exception(vcpu, &exit_qual)) {
-		if (vmx->nested.nested_run_pending)
+		if (block_nested_events)
 			return -EBUSY;
 		nested_vmx_inject_exception_vmexit(vcpu, exit_qual);
 		vcpu->arch.exception.pending = false;
@@ -11129,14 +11128,14 @@ static int vmx_check_nested_events(struc
 
 	if (nested_cpu_has_preemption_timer(get_vmcs12(vcpu)) &&
 	    vmx->nested.preemption_timer_expired) {
-		if (vmx->nested.nested_run_pending)
+		if (block_nested_events)
 			return -EBUSY;
 		nested_vmx_vmexit(vcpu, EXIT_REASON_PREEMPTION_TIMER, 0, 0);
 		return 0;
 	}
 
 	if (vcpu->arch.nmi_pending && nested_exit_on_nmi(vcpu)) {
-		if (vmx->nested.nested_run_pending)
+		if (block_nested_events)
 			return -EBUSY;
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
 				  NMI_VECTOR | INTR_TYPE_NMI_INTR |
@@ -11152,7 +11151,7 @@ static int vmx_check_nested_events(struc
 
 	if ((kvm_cpu_has_interrupt(vcpu) || external_intr) &&
 	    nested_exit_on_intr(vcpu)) {
-		if (vmx->nested.nested_run_pending)
+		if (block_nested_events)
 			return -EBUSY;
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT, 0, 0);
 		return 0;


Patches currently in stable-queue which might be from liran.alon@oracle.com are

queue-4.14/kvm-nvmx-fix-vmx_check_nested_events-return-value-in-case-an-event-was-reinjected-to-l2.patch
queue-4.14/kvm-x86-don-t-re-execute-instruction-when-not-passing-cr2-value.patch
queue-4.14/kvm-x86-ioapic-preserve-read-only-values-in-the-redirection-table.patch
queue-4.14/kvm-x86-ioapic-fix-level-triggered-eoi-and-ioapic-reconfigure-race.patch
queue-4.14/kvm-x86-emulator-return-to-user-mode-on-l1-cpl-0-emulation-failure.patch
queue-4.14/kvm-nvmx-nsvm-don-t-intercept-ud-when-running-l2.patch
queue-4.14/kvm-x86-ioapic-clear-remote-irr-when-entry-is-switched-to-edge-triggered.patch