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From: Dave Hansen <[email protected]>
To: Jethro Beekman <[email protected]>,
	Cathy Zhang <[email protected]>,
	[email protected], [email protected]
Cc: [email protected]
Subject: Re: [RFC PATCH v2 09/10] x86/cpu: Call ENCLS[EUPDATESVN] procedure in microcode update
Date: Wed, 16 Mar 2022 08:42:33 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 3/16/22 02:46, Jethro Beekman wrote:
>> +void update_cpusvn_intel(void) +{ +	sgx_lock_epc(); +	if
>> (sgx_zap_pages())
> Doing this automatically and unconditionally during a microcode
> update seems undesirable. This requires the userland tooling that is
> coordinating the microcode update to be aware of any SGX enclaves
> that are running and possibly coordinate sequencing with the
> processes containing those enclaves. This coupling does not exist
> today.

"Today" in what?

If a microcode update changes SGX behavior and bumps CPUSVN, it's
fundamentally incompatible with letting enclaves continue to run.  They
might as well be killed.

But, seriously, if you can't handle enclaves being killed every few
months, don't use SGX.  The architecture doesn't allow data to be
persistent like normal x86.  It's fundamental to the architecture.  You
can also think of this as a shiny new SGX *testing* feature: one that
keeps enclave owners from becoming complacent and forgetting about what
the SGX architecture provides.


  parent reply	other threads:[~2022-03-16 15:43 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-15  1:02 [RFC PATCH v2 00/10] Support microcode updates affecting SGX Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 01/10] x86/sgx: Introduce mechanism to prevent new initializations of EPC pages Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 02/10] x86/sgx: Provide VA page non-NULL owner Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 03/10] x86/sgx: Save enclave pointer for VA page Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 04/10] x86/sgx: Keep record for SGX VA and Guest page type Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 05/10] x86/sgx: Save the size of each EPC section Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 06/10] x86/sgx: Forced EPC page zapping for EUPDATESVN Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 07/10] x86/sgx: Define error codes for ENCLS[EUPDATESVN] Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 08/10] x86/sgx: Implement ENCLS[EUPDATESVN] Cathy Zhang
2022-03-15  1:02 ` [RFC PATCH v2 09/10] x86/cpu: Call ENCLS[EUPDATESVN] procedure in microcode update Cathy Zhang
     [not found]   ` <[email protected]>
2022-03-16 15:42     ` Dave Hansen [this message]
     [not found]     ` <[email protected]>
2022-03-16 15:47       ` Dave Hansen
2022-03-15  1:03 ` [RFC PATCH v2 10/10] x86/sgx: Call ENCLS[EUPDATESVN] during SGX initialization Cathy Zhang

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