--- /dev/null
+From 530cf09088939c7c9464cb6b21039a1d0422855c Mon Sep 17 00:00:00 2001
+From: Paolo Bonzini <pbonzini@redhat.com>
+Date: Fri, 26 Apr 2019 09:34:01 -0700
+Subject: KVM: fail KVM_SET_VCPU_EVENTS with invalid exception number
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+commit 78e546c824fa8f96d323b7edd6f5cad5b74af057 upstream
+
+This cannot be returned by KVM_GET_VCPU_EVENTS, so it is okay to return
+EINVAL. It causes a WARN from exception_type:
+
+ WARNING: CPU: 3 PID: 16732 at arch/x86/kvm/x86.c:345 exception_type+0x49/0x50 [kvm]()
+ CPU: 3 PID: 16732 Comm: a.out Tainted: G W 4.4.6-300.fc23.x86_64 #1
+ Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012
+ 0000000000000286 000000006308a48b ffff8800bec7fcf8 ffffffff813b542e
+ 0000000000000000 ffffffffa0966496 ffff8800bec7fd30 ffffffff810a40f2
+ ffff8800552a8000 0000000000000000 00000000002c267c 0000000000000001
+ Call Trace:
+ [<ffffffff813b542e>] dump_stack+0x63/0x85
+ [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0
+ [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20
+ [<ffffffffa0924809>] exception_type+0x49/0x50 [kvm]
+ [<ffffffffa0934622>] kvm_arch_vcpu_ioctl_run+0x10a2/0x14e0 [kvm]
+ [<ffffffffa091c04d>] kvm_vcpu_ioctl+0x33d/0x620 [kvm]
+ [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
+ [<ffffffff812414a9>] SyS_ioctl+0x79/0x90
+ [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71
+ ---[ end trace b1a0391266848f50 ]---
+
+Testcase (beautified/reduced from syzkaller output):
+
+ #include <unistd.h>
+ #include <sys/syscall.h>
+ #include <string.h>
+ #include <stdint.h>
+ #include <fcntl.h>
+ #include <sys/ioctl.h>
+ #include <linux/kvm.h>
+
+ long r[31];
+
+ int main()
+ {
+ memset(r, -1, sizeof(r));
+ r[2] = open("/dev/kvm", O_RDONLY);
+ r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
+ r[7] = ioctl(r[3], KVM_CREATE_VCPU, 0);
+
+ struct kvm_vcpu_events ve = {
+ .exception.injected = 1,
+ .exception.nr = 0xd4
+ };
+ r[27] = ioctl(r[7], KVM_SET_VCPU_EVENTS, &ve);
+ r[30] = ioctl(r[7], KVM_RUN, 0);
+ return 0;
+ }
+
+Reported-by: Dmitry Vyukov <dvyukov@google.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
+Signed-off-by: Zubin Mithra <zsm@chromium.org>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/x86/kvm/x86.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
+index 706c5d63a53f..d830a0d60ba4 100644
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -2972,6 +2972,10 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
+ | KVM_VCPUEVENT_VALID_SMM))
+ return -EINVAL;
+
++ if (events->exception.injected &&
++ (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR))
++ return -EINVAL;
++
+ /* INITs are latched while in SMM */
+ if (events->flags & KVM_VCPUEVENT_VALID_SMM &&
+ (events->smi.smm || events->smi.pending) &&
+--
+2.19.1
+