From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: Failed vm entry with heavy use of emulator Date: Tue, 5 Jan 2016 13:49:12 +0000 Message-ID: <568BC9D8.8030709@citrix.com> References: <568BAF7E.802@citrix.com> <568BC7A2.3020901@bitdefender.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <568BC7A2.3020901@bitdefender.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 05/01/16 13:39, Razvan Cojocaru wrote: > On 01/05/2016 01:56 PM, Andrew Cooper wrote: >> On 05/01/16 11:49, Tamas K Lengyel wrote: >>> Hi all, >>> I've been stress-testing the built-in emulator using the vm_event >>> response VM_EVENT_FLAG_EMULATE feature. In the test I've turned all >>> pages non-readable by default and all trapped instructions to be >>> emulated. My test code can be found at >>> https://github.com/tklengyel/xen/compare/read_emul?expand=1. >>> >>> The following crash is reproducible and has been verified by Razvan as >>> well. >>> >>> (XEN) p2m.c:1726:d1v0 calling mem_access_emulate_one, kind 0 >>> (XEN) Failed vm entry (exit reason 0x80000021) caused by invalid guest >>> state (0). >>> (XEN) ************* VMCS Area ************** >>> (XEN) *** Guest State *** >>> (XEN) CR0: actual=0x000000008001003b, shadow=0x000000008001003b, >>> gh_mask=ffffffffffffffff >>> (XEN) CR4: actual=0x00000000000426f9, shadow=0x00000000000406f9, >>> gh_mask=ffffffffffffffff >>> (XEN) CR3 = 0x0000000000185000 >>> (XEN) PDPTE0 = 0x0000000000186001 PDPTE1 = 0x0000000000187001 >>> (XEN) PDPTE2 = 0x0000000000188001 PDPTE3 = 0x0000000000189001 >>> (XEN) RSP = 0x000000008276dc28 (0x000000008276dc28) RIP = >>> 0x00000000826bce1c (0x00000000826bce1c) >>> (XEN) RFLAGS=0x00000002 (0x00000002) DR7 = 0x0000000000000400 >>> (XEN) Sysenter RSP=000000008078b000 CS:RIP=0008:00000000826830c0 >>> (XEN) sel attr limit base >>> (XEN) CS: 0008 0c09b ffffffff 0000000000000000 >>> (XEN) DS: 0023 0c0f3 ffffffff 0000000000000000 >>> (XEN) SS: 0010 0c093 ffffffff 0000000000000000 >>> (XEN) ES: 0023 0c0f3 ffffffff 0000000000000000 >>> (XEN) FS: 0030 04093 00003748 0000000082770c00 >>> (XEN) GS: 0000 1c000 ffffffff 0000000000000000 >>> (XEN) GDTR: 000003ff 0000000080b95000 >>> (XEN) LDTR: 0000 1c000 ffffffff 0000000000000000 >>> (XEN) IDTR: 000007ff 0000000080b95400 >>> (XEN) TR: 0028 0008b 000020ab 00000000801da000 >>> (XEN) EFER = 0x0000000000000000 PAT = 0x0007010600070106 >>> (XEN) PreemptionTimer = 0x00000000 SM Base = 0x00000000 >>> (XEN) DebugCtl = 0x0000000000000000 DebugExceptions = 0x0000000000000000 >>> (XEN) Interruptibility = 00000000 ActivityState = 00000000 >>> (XEN) *** Host State *** >>> (XEN) RIP = 0xffff82d0802075c0 (vmx_asm_vmexit_handler) RSP = >>> 0xffff830430d97f90 >>> (XEN) CS=e008 SS=0000 DS=0000 ES=0000 FS=0000 GS=0000 TR=e040 >>> (XEN) FSBase=0000000000000000 GSBase=0000000000000000 >>> TRBase=ffff830430d9bc00 >>> (XEN) GDTBase=ffff830430d8c000 IDTBase=ffff830430d98000 >>> (XEN) CR0=000000008005003b CR3=00000004136d0000 CR4=00000000000426e0 >>> (XEN) Sysenter RSP=ffff830430d97fc0 CS:RIP=e008:ffff82d08024db30 >>> (XEN) EFER = 0x0000000000000000 PAT = 0x0000050100070406 >>> (XEN) *** Control State *** >>> (XEN) PinBased=0000003f CPUBased=b6a075fa SecondaryExec=000000eb >>> (XEN) EntryControls=000051ff ExitControls=000fefff >>> (XEN) ExceptionBitmap=00060042 PFECmask=00000000 PFECmatch=00000000 >>> (XEN) VMEntry: intr_info=800000d1 errcode=00000000 ilen=00000000 >>> (XEN) VMExit: intr_info=00000000 errcode=00000000 ilen=00000003 >>> (XEN) reason=80000021 qualification=0000000000000000 >>> (XEN) IDTVectoring: info=800000d1 errcode=00000000 >>> (XEN) TSC Offset = 0x0000004ed9c86354 >>> (XEN) TPR Threshold = 0x00 PostedIntrVec = 0x00 >>> (XEN) EPT pointer = 0x000000041124e01e EPTP index = 0x0000 >>> (XEN) Virtual processor ID = 0x0011 VMfunc controls = 0000000000000000 >>> (XEN) ************************************** >>> (XEN) domain_crash called from vmx.c:2761 >>> >>> Any tips on how to further debug this issue? >> Do you have a log of the instructions emulated? > Here's a quick log of the emulated instructions on my setup: > http://pastebin.com/raw/XXQ0Lnzh Hmm - according to that, the final instruction emulated was d1v0 32bit @ 0008:828925db -> fa which is the 'cli' instruction. I would start there - I doubt it is an instruction which is emulated often. ~Andrew