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From: "Haitao Huang" <haitao.huang@linux.intel.com>
To: "Christopherson,, Sean" <seanjc@google.com>,
	"Huang, Kai" <kai.huang@intel.com>
Cc: "Zhang, Bo" <zhanb@microsoft.com>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
	"yangjie@microsoft.com" <yangjie@microsoft.com>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"Li, Zhiquan1" <zhiquan1.li@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"tj@kernel.org" <tj@kernel.org>,
	"anakrish@microsoft.com" <anakrish@microsoft.com>,
	"jarkko@kernel.org" <jarkko@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"mikko.ylinen@linux.intel.com" <mikko.ylinen@linux.intel.com>,
	"Mehta, Sohil" <sohil.mehta@intel.com>,
	"bp@alien8.de" <bp@alien8.de>, "x86@kernel.org" <x86@kernel.org>,
	"kristen@linux.intel.com" <kristen@linux.intel.com>
Subject: Re: [PATCH v5 12/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC
Date: Tue, 17 Oct 2023 07:58:02 -0500	[thread overview]
Message-ID: <op.2cyma0e9wjvjmi@hhuan26-mobl.amr.corp.intel.com> (raw)
In-Reply-To: <915907d56861ef4aa7f9f68e0eb8d136a60bee39.camel@intel.com>

On Mon, 16 Oct 2023 20:34:57 -0500, Huang, Kai <kai.huang@intel.com> wrote:

> On Mon, 2023-10-16 at 19:10 -0500, Haitao Huang wrote:
>> On Mon, 16 Oct 2023 16:09:52 -0500, Huang, Kai <kai.huang@intel.com>  
>> wrote:
>> [...]
>>
>> > still need to fix the bug mentioned above here.
>> >
>> > I really think you should just go this simple way:
>> >
>> > When you want to take EPC back from VM, kill the VM.
>> >
>>
>> My only concern is that this is a compromise due to current limitation  
>> (no
>> other sane way to take EPC from VMs). If we define this behavior and it
>> becomes a contract to user space, then we can't change in future.
>
> Why do we need to "define such behaviour"?
>
> This isn't some kinda of kernel/userspace ABI IMHO, but only kernel  
> internal
> implementation.  Here VM is similar to normal host enclaves.  You limit  
> the
> resource, some host enclaves could be killed.  Similarly, VM could also  
> be
> killed too.
>
> And supporting VMM EPC oversubscription doesn't mean VM won't be  
> killed.  The VM
> can still be a target to kill after VM's all EPC pages have been swapped  
> out.
>
>>
>> On the other hand, my understanding the reason you want this behavior is
>> to enforce EPC limit at runtime.
>
> No I just thought this is a bug/issue needs to be fixed.  If anyone  
> believes
> this is not a bug/issue then it's a separate discussion.
>

AFAIK, before we introducing max_write() callback in this series, no misc  
controller would possibly enforce the limit when misc.max is reduced. e.g.  
I don't think CVMs be killed when ASID limit is reduced and the cgroup was  
full before limit is reduced.

I think EPC pages to VMs could have the same behavior, once they are given  
to a guest, never taken back by the host. For enclaves on host side, pages  
are reclaimable, that allows us to enforce in a similar way to memcg.

Thanks
Haitao

  reply	other threads:[~2023-10-17 12:58 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-23  3:06 [PATCH v5 00/18] Add Cgroup support for SGX EPC memory Haitao Huang
2023-09-23  3:06 ` [PATCH v5 01/18] cgroup/misc: Add per resource callbacks for CSS events Haitao Huang
2023-09-25 17:09   ` Jarkko Sakkinen
2023-09-26  3:04     ` Haitao Huang
2023-09-26 13:10       ` Jarkko Sakkinen
2023-09-26 13:13         ` Jarkko Sakkinen
2023-09-27  1:56           ` Haitao Huang
2023-10-02 22:47             ` Jarkko Sakkinen
2023-10-02 22:55               ` Jarkko Sakkinen
2023-10-04 15:45                 ` Haitao Huang
2023-10-04 17:18                   ` Tejun Heo
2023-09-27  9:20   ` Huang, Kai
2023-10-03 14:29     ` Haitao Huang
2023-10-17 18:55   ` Michal Koutný
2023-09-23  3:06 ` [PATCH v5 02/18] cgroup/misc: Add SGX EPC resource type and export APIs for SGX driver Haitao Huang
2023-09-25 18:50   ` Tejun Heo
2023-09-28  3:59   ` Huang, Kai
2023-10-03  7:00     ` Haitao Huang
2023-10-03 19:33       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 03/18] x86/sgx: Add sgx_epc_lru_lists to encapsulate LRU lists Haitao Huang
2023-09-23  3:06 ` [PATCH v5 04/18] x86/sgx: Use sgx_epc_lru_lists for existing active page list Haitao Huang
2023-09-23  3:06 ` [PATCH v5 05/18] x86/sgx: Store reclaimable EPC pages in sgx_epc_lru_lists Haitao Huang
2023-09-27 10:14   ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 06/18] x86/sgx: Introduce EPC page states Haitao Huang
2023-09-25 17:11   ` Jarkko Sakkinen
2023-09-27 10:28   ` Huang, Kai
2023-10-03  4:49     ` Haitao Huang
2023-10-03 20:03       ` Huang, Kai
2023-10-04 15:24         ` Haitao Huang
2023-10-04 21:05           ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 07/18] x86/sgx: Introduce RECLAIM_IN_PROGRESS state Haitao Huang
2023-09-25 17:13   ` Jarkko Sakkinen
2023-09-27 10:42   ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 08/18] x86/sgx: Use a list to track to-be-reclaimed pages Haitao Huang
2023-09-28  9:28   ` Huang, Kai
2023-10-03  5:09     ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 09/18] x86/sgx: Store struct sgx_encl when allocating new VA pages Haitao Huang
2023-09-27 11:14   ` Huang, Kai
2023-09-27 15:35     ` Haitao Huang
2023-09-27 21:21       ` Huang, Kai
2023-09-29 15:06         ` Haitao Huang
2023-10-02 11:05           ` Huang, Kai
2023-09-27 11:35   ` Huang, Kai
2023-10-03  6:45     ` Haitao Huang
2023-10-03 20:07       ` Huang, Kai
2023-10-04 15:03         ` Haitao Huang
2023-10-04 21:13           ` Huang, Kai
2023-10-05  4:22             ` Haitao Huang
2023-10-05  6:49               ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 10/18] x86/sgx: Add EPC page flags to identify owner types Haitao Huang
2023-09-23  3:06 ` [PATCH v5 11/18] x86/sgx: store unreclaimable pages in LRU lists Haitao Huang
2023-09-27 11:57   ` Huang, Kai
2023-10-03  5:42     ` Haitao Huang
2023-09-28  9:41   ` Huang, Kai
2023-10-03  5:15     ` Haitao Huang
2023-10-03 20:12       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 12/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Haitao Huang
2023-10-09 23:45   ` Huang, Kai
2023-10-10  0:23     ` Sean Christopherson
2023-10-10  0:50       ` Huang, Kai
2023-10-10  1:34         ` Huang, Kai
2023-10-10 16:49           ` Haitao Huang
2023-10-11  0:51             ` Huang, Kai
2023-10-12 13:27               ` Haitao Huang
2023-10-16 10:57                 ` Huang, Kai
2023-10-16 19:52                   ` Haitao Huang
2023-10-16 21:09                     ` Huang, Kai
2023-10-17  0:10                       ` Haitao Huang
2023-10-17  1:34                         ` Huang, Kai
2023-10-17 12:58                           ` Haitao Huang [this message]
2023-10-17 18:54                             ` Michal Koutný
2023-10-17 19:13                               ` Michal Koutný
2023-10-18  4:39                                 ` Haitao Huang
2023-10-18  4:37                               ` Haitao Huang
2023-10-18 13:55                                 ` Dave Hansen
2023-10-18 15:26                                   ` Haitao Huang
2023-10-18 15:37                                     ` Dave Hansen
2023-10-18 15:52                                       ` Michal Koutný
2023-10-18 16:25                                         ` Haitao Huang
2023-10-16 21:32                     ` Sean Christopherson
2023-10-17  0:09                       ` Haitao Huang
2023-10-17 15:43                         ` Sean Christopherson
2023-10-17 11:49                       ` Mikko Ylinen
2023-10-11  1:14             ` Huang, Kai
2023-10-16 11:02               ` Huang, Kai
2023-10-10  1:42       ` Haitao Huang
2023-10-10  2:23         ` Huang, Kai
2023-10-10 13:26           ` Haitao Huang
2023-10-11  0:01             ` Sean Christopherson
2023-10-11 15:02               ` Haitao Huang
2023-10-10  1:04     ` Haitao Huang
2023-10-10  1:18       ` Huang, Kai
2023-10-10  1:38         ` Haitao Huang
2023-10-10  2:12           ` Huang, Kai
2023-10-10 17:05             ` Haitao Huang
2023-10-11  0:31               ` Huang, Kai
2023-10-11 16:04                 ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 13/18] x86/sgx: Expose sgx_reclaim_pages() for use by EPC cgroup Haitao Huang
2023-10-05 12:24   ` Huang, Kai
2023-10-05 19:23     ` Haitao Huang
2023-10-05 20:25       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 14/18] x86/sgx: Add helper to grab pages from an arbitrary EPC LRU Haitao Huang
2023-09-23  3:06 ` [PATCH v5 15/18] x86/sgx: Prepare for multiple LRUs Haitao Huang
2023-10-05 12:30   ` Huang, Kai
2023-10-05 19:33     ` Haitao Huang
2023-10-05 20:38       ` Huang, Kai
2023-09-23  3:06 ` [PATCH v5 16/18] x86/sgx: Limit process EPC usage with misc cgroup controller Haitao Huang
2023-09-25 17:15   ` Jarkko Sakkinen
2023-10-05 21:01   ` Huang, Kai
2023-10-10  0:12   ` Huang, Kai
2023-10-10  0:16   ` Huang, Kai
2023-10-10  0:26   ` Huang, Kai
2023-10-22 18:26     ` Haitao Huang
2023-10-10  9:19   ` Huang, Kai
2023-10-10  9:32   ` Huang, Kai
2023-10-17 18:54   ` Michal Koutný
2023-10-19 16:05     ` Haitao Huang
2023-09-23  3:06 ` [PATCH v5 17/18] Docs/x86/sgx: Add description for cgroup support Haitao Huang
2023-09-23  3:06 ` [PATCH v5 18/18] selftests/sgx: Add scripts for EPC cgroup testing Haitao Huang

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