From: Dave Hansen <dave.hansen@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: x86@kernel.org, linux-sgx@vger.kernel.org, jarkko@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: Mon, 13 Sep 2021 12:25:33 -0700 [thread overview]
Message-ID: <fa8e8573-d907-11b0-60e1-f31e050beb64@intel.com> (raw)
In-Reply-To: <2b595588-eb98-6d30-dc50-794fc396bf7e@redhat.com>
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.
Windows has these expectations about booting with fully uninitialized
state. There are also a number of environments where QEMU is sandboxed
or drops permissions in a way that prevent free and open access to
/dev/sgx_vepc.
So good so far?
next prev parent reply other threads:[~2021-09-13 19:25 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 [this message]
2021-09-13 21:16 ` Jarkko Sakkinen
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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