From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 111BE81F06 for ; Wed, 30 Nov 2016 02:08:12 -0800 (PST) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CC2CE804F2; Wed, 30 Nov 2016 08:47:43 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-51.phx2.redhat.com [10.3.116.51]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAU8lfMk016996; Wed, 30 Nov 2016 03:47:42 -0500 To: "Fan, Jeff" , "edk2-devel@ml01.01.org" References: <20161129075130.15192-1-jeff.fan@intel.com> <542CF652F8836A4AB8DBFAAD40ED192A4A2EB3A8@shsmsx102.ccr.corp.intel.com> Cc: "Kinney, Michael D" , "Tian, Feng" , "Yao, Jiewen" From: Laszlo Ersek Message-ID: Date: Wed, 30 Nov 2016 09:47:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.0 MIME-Version: 1.0 In-Reply-To: <542CF652F8836A4AB8DBFAAD40ED192A4A2EB3A8@shsmsx102.ccr.corp.intel.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 30 Nov 2016 08:47:43 +0000 (UTC) Subject: Re: [PATCH] UefiCpuPkg/PiSmmCpuDxeSmm: Clear some semaphores on S3 boot path X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Nov 2016 10:08:16 -0000 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit On 11/30/16 01:43, Fan, Jeff wrote: > Laszlo, > > Thanks your comments. I added my comments as below in [Jeff] Thanks for your answers. Acked-by: Laszlo Ersek Tested-by: Laszlo Ersek Cheers Laszlo > -----Original Message----- > From: Laszlo Ersek [mailto:lersek@redhat.com] > Sent: Wednesday, November 30, 2016 4:49 AM > To: Fan, Jeff; edk2-devel@ml01.01.org > Cc: Kinney, Michael D; Yao, Jiewen; Tian, Feng > Subject: Re: [edk2] [PATCH] UefiCpuPkg/PiSmmCpuDxeSmm: Clear some semaphores on S3 boot path > > On 11/29/16 08:51, Jeff Fan wrote: >> Some semaphores are not cleared on S3 boot path. For example, >> mSmmMpSyncData->CpuData[CpuIndex].Present. It may still keeps the >> mSmmMpSyncData->value set at >> SMM runtime during S3 resume. It may causes BSP have the wrong >> judgement on SMM AP's present state. >> >> We have one related fix at e78a2a49ee6b0c0d7c6997c87ace31d7761cf636. >> But that is not completed. >> >> This fix is to clear Busy/Run/Present semaphores in InitializeMpSyncData(). >> >> Cc: Laszlo Ersek >> Cc: Feng Tian >> Cc: Jiewen Yao >> Cc: Michael D Kinney >> Contributed-under: TianoCore Contribution Agreement 1.0 >> Signed-off-by: Jeff Fan >> --- >> UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c >> b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c >> index cfbf59e..a873b68 100644 >> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c >> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c >> @@ -1357,6 +1357,9 @@ InitializeMpSyncData ( >> (UINT32 *)((UINTN)mSmmCpuSemaphores.SemaphoreCpu.Run + mSemaphoreSize * CpuIndex); >> mSmmMpSyncData->CpuData[CpuIndex].Present = >> (BOOLEAN *)((UINTN)mSmmCpuSemaphores.SemaphoreCpu.Present + >> mSemaphoreSize * CpuIndex); >> + *(mSmmMpSyncData->CpuData[CpuIndex].Busy) = 0; >> + *(mSmmMpSyncData->CpuData[CpuIndex].Run) = 0; >> + *(mSmmMpSyncData->CpuData[CpuIndex].Present) = FALSE; >> } >> } >> } >> > > Even after this patch, the values pointed-to by the following fields of SemaphoreGlobal are not cleared: PFLock, CodeAccessCheckLock, MemoryMappedLock. Is that okay? > > The values pointed-to by the following fields of SemaphoreMsr are not cleared either: Msr, AvailableCounter. Is that okay? > > [Jeff] We need to clear the data in SMM_CPU_DATA_BLOCK/SMM_DISPATCHER_MP_SYNC_DATA and semaphores pointed by the field in those 2 structures. However, the other spinlock located in SemaphoreBlock needn't to be cleared. > > Can we imitate e78a2a49ee6b0c0d7c6997c87ace31d7761cf636 here; namely, can we save "SemaphoreBlock" and "TotalSize" from > InitializeSmmCpuSemaphores() in global variables (in SMRAM), and then just do another ZeroMem() here? That would cover the currently listed objects (*Counter, *InsideSmm, *AllCpusInSync), and everything else too, in a future-proof way. > > [Jeff] This issue is that ZeroMem only clear all the fields in structure and needn't o clear the buffer pointed by these fields. > > In fact, I wonder if the ZeroMem() could be moved into > InitializeMpSyncData() from InitializeSmmCpuSemaphores(). > > [Jeff] If we cleared all semaphores(including Spinlock), we need to re-initialize them again. I do not think there is some reasonable usage case to let spinlock keep the garbage value. > > Of course, if some pointed-to objects must not be cleared, then the > ZeroMem() is not appropriate. > > [Jeff] Agree. > > Thanks! > Laszlo > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel >