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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
	dave.hansen@linux.intel.com, yang.zhong@intel.com
Subject: Re: [PATCH 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page
Date: Tue, 14 Sep 2021 00:16:37 +0300	[thread overview]
Message-ID: <de03361aab108ff481f6472978265e754100c6fb.camel@kernel.org> (raw)
In-Reply-To: <fa8e8573-d907-11b0-60e1-f31e050beb64@intel.com>

On Mon, 2021-09-13 at 12:25 -0700, Dave Hansen wrote:
> On 9/13/21 11:35 AM, Paolo Bonzini wrote:
> > > > Apart from reclaiming, /dev/sgx_vepc might disappear between the first
> > > > open() and subsequent ones.
> > > 
> > > Aside from it being rm'd, I don't think that's possible.
> > > 
> > 
> > Being rm'd would be a possibility in principle, and it would be ugly for
> > it to cause issues on running VMs.  Also I'd like for it to be able to
> > pass /dev/sgx_vepc in via a file descriptor, and run QEMU in a chroot or
> > a mount namespace.  Alternatively, with seccomp it may be possible to
> > sandbox a running QEMU process in such a way that open() is forbidden at
> > runtime (all hotplug is done via file descriptor passing); it is not yet
> > possible, but it is a goal.
> 
> OK, so maybe another way of saying this:
> 
> For bare-metal SGX on real hardware, the hardware provides guarantees
> SGX state at reboot.  For instance, all pages start out uninitialized.
> The vepc driver provides a similar guarantee today for freshly-opened
> vepc instances.
> 
> But, vepc users have a problem: they might want to run an OS that
> expects to be booted with clean, fully uninitialized SGX state, just as
> it would be on bare-metal.  Right now, the only way to get that is to
> create a new vepc instance.  That might not be possible in all
> configurations, like if the permission to open(/dev/sgx_vepc) has been
> lost since the VM was first booted.

So you maintain your systems in a way that this does not happen?

/Jarkko

  reply	other threads:[~2021-09-13 21:16 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-13 13:11 [RFC/RFT PATCH 0/2] x86: sgx_vepc: implement ioctl to EREMOVE all pages Paolo Bonzini
2021-09-13 13:11 ` [PATCH 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page Paolo Bonzini
2021-09-13 14:05   ` Dave Hansen
2021-09-13 14:24     ` Paolo Bonzini
2021-09-13 14:55       ` Dave Hansen
2021-09-13 15:14         ` Paolo Bonzini
2021-09-13 15:29           ` Dave Hansen
2021-09-13 18:35             ` Paolo Bonzini
2021-09-13 19:25               ` Dave Hansen
2021-09-13 21:16                 ` Jarkko Sakkinen [this message]
2021-09-13 21:15               ` Jarkko Sakkinen
2021-09-13 21:13           ` Jarkko Sakkinen
2021-09-14  5:36             ` Paolo Bonzini
2021-09-14 16:05               ` Jarkko Sakkinen
2021-09-13 21:12         ` Jarkko Sakkinen
2021-09-13 21:00       ` Jarkko Sakkinen
2021-09-13 20:33   ` Jarkko Sakkinen
2021-09-13 13:11 ` [PATCH 2/2] x86: sgx_vepc: implement SGX_IOC_VEPC_REMOVE ioctl Paolo Bonzini
2021-09-13 19:33   ` Dave Hansen
2021-09-13 21:11     ` Sean Christopherson
2021-09-13 22:43       ` Dave Hansen
2021-09-14 10:55   ` Kai Huang
2021-09-14  7:10 ` [RFC/RFT PATCH 0/2] x86: sgx_vepc: implement ioctl to EREMOVE all pages Yang Zhong
2021-09-14 10:19   ` Paolo Bonzini
2021-09-14 16:42     ` Jarkko Sakkinen
2021-09-14 17:07       ` Paolo Bonzini
2021-09-14 17:40         ` Jarkko Sakkinen
2021-09-14 17:44           ` Jarkko Sakkinen
2021-09-15  8:28     ` Yang Zhong
2021-09-20 12:53 [PATCH " Paolo Bonzini
2021-09-20 12:54 ` [PATCH 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page Paolo Bonzini
2021-09-21 19:44   ` Jarkko Sakkinen
2021-09-21 19:46     ` Jarkko Sakkinen
2021-09-23 12:08     ` Paolo Bonzini
2021-09-23 20:33       ` Jarkko Sakkinen

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