From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Wed, 1 Aug 2018 11:47:50 +0000 (+0100)
Subject: x86/vmx: Avoid hitting BUG_ON() after EPTP-related domain_crash()
X-Git-Tag: 4.12.0-rc1~875
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=48dbb2dbe9d9f92a2890a15bb48a0598c065b9f8;p=xen.git

x86/vmx: Avoid hitting BUG_ON() after EPTP-related domain_crash()

If the EPTP pointer can't be located in the altp2m list, the domain
is (legitimately) crashed.

Under those circumstances, execution will continue and guarentee to hit the
BUG_ON(idx >= MAX_ALTP2M) (unfortunately, just out of context).

Return from vmx_vmexit_handler() after the domain_crash(), which also has the
side effect of reentering the scheduler more promptly.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
---

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index bcf95f9a5f..257efbe322 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3666,6 +3666,8 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
             {
                 gdprintk(XENLOG_ERR, "EPTP not found in alternate p2m list\n");
                 domain_crash(v->domain);
+
+                return;
             }
         }