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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Hillf Danton <hdanton@sina.com>
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Serge Ayoun <serge.ayoun@intel.com>,
	akpm@linux-foundation.org
Subject: Re: [PATCH v41 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE
Date: Tue, 17 Nov 2020 19:35:06 +0200
Message-ID: <20201117173506.GB8524@kernel.org> (raw)
In-Reply-To: <20201115044044.11040-1-hdanton@sina.com>

On Sun, Nov 15, 2020 at 12:40:44PM +0800, Hillf Danton wrote:
> On Fri, 13 Nov 2020 00:01:23 +0200 Jarkko Sakkinen wrote:
> > 
> > +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> > +{
> > +	struct sgx_encl *encl = filep->private_data;
> > +	int ret;
> > +
> > +	if (test_and_set_bit(SGX_ENCL_IOCTL, &encl->flags))
> > +		return -EBUSY;
> 
> Looks like encl->ioctl_mutex is needed to exlusively serialize
> concurrent ioctl threads and make encl->flags free of the duty.
> Plus it can cut the confusing EBUSY in userspace as it is not
> a critical path in any form.

The reason it is there was lock juggling with sgx_encl_grow() [*].

Andd since you never should use these ioctl's in parallel so why not
explicitly signal it to the user space?

[*] https://lore.kernel.org/linux-sgx/20190827001128.25066-4-sean.j.christopherson@intel.com/

/Jarkko

  parent reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12 22:01 [PATCH v41 00/24] Intel SGX foundations Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 01/24] x86/sgx: Add SGX architectural data structures Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 02/24] x86/sgx: Add wrappers for ENCLS functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 03/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 04/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 05/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-11-16 22:25   ` [PATCH] x86/sgx: clarify 'laundry_list' locking Dave Hansen
2020-11-17 19:29     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 06/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 07/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 08/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 09/24] x86/sgx: Add SGX page allocator functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-11-13 10:25   ` Mel Gorman
2020-11-17 18:16     ` Jarkko Sakkinen
2020-11-15 17:08   ` Dr. Greg
2020-11-15 17:32   ` Matthew Wilcox
2020-11-15 18:36     ` Dave Hansen
2020-11-16 10:09       ` Mel Gorman
2020-11-17 19:15         ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 11/24] x86/sgx: Add SGX misc driver interface Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
     [not found]   ` <20201115044044.11040-1-hdanton@sina.com>
2020-11-17 17:35     ` Jarkko Sakkinen [this message]
2020-11-12 22:01 ` [PATCH v41 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 16/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 17/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 18/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 19/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-11-17 13:14   ` Borislav Petkov
2020-11-17 19:41     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 20/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-11-16 18:19   ` Shuah Khan
2020-11-17 13:22     ` Borislav Petkov
2020-11-17 19:42     ` Jarkko Sakkinen
2020-11-17 17:26   ` Borislav Petkov
2020-11-17 21:27     ` Jarkko Sakkinen
2020-11-17 21:38     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 21/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 22/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 23/24] docs: x86/sgx: Document SGX kernel architecture Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-11-16 16:55 ` [PATCH v41 00/24] Intel SGX foundations Borislav Petkov
2020-11-16 17:21   ` Dave Hansen
2020-11-16 17:28     ` Borislav Petkov
2020-11-17 19:20       ` Jarkko Sakkinen
     [not found] ` <20201114084211.5284-1-hdanton@sina.com>
2020-11-16 18:33   ` [PATCH v41 05/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Dave Hansen
     [not found] ` <20201115040127.7804-1-hdanton@sina.com>
2020-11-16 21:11   ` [PATCH v41 11/24] x86/sgx: Add SGX misc driver interface Dave Hansen
     [not found] ` <20201114090708.8684-1-hdanton@sina.com>
2020-11-17 18:12   ` [PATCH v41 06/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
     [not found] ` <20201114093256.7800-1-hdanton@sina.com>
2020-11-17 18:14   ` [PATCH v41 09/24] x86/sgx: Add SGX page allocator functions Jarkko Sakkinen
     [not found] ` <20201115030548.1572-1-hdanton@sina.com>
2020-11-17 18:22   ` [PATCH v41 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-12-15  5:38 ` [PATCH v41 00/24] Intel SGX foundations Hui, Chunyang
2020-12-15  5:43 ` Hui, Chunyang
2020-12-15 15:58   ` Jarkko Sakkinen

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