From: Dave Hansen <dave.hansen@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: dave.hansen@linux.intel.com, seanjc@google.com, x86@kernel.org,
yang.zhong@intel.com, jarkko@kernel.org
Subject: Re: [PATCH v2 2/2] x86: sgx_vepc: implement SGX_IOC_VEPC_REMOVE ioctl
Date: Thu, 14 Oct 2021 15:14:33 -0700 [thread overview]
Message-ID: <a6f18a62-4e3e-b641-5ef9-4ada9eccd74d@intel.com> (raw)
In-Reply-To: <20211012105708.2070480-3-pbonzini@redhat.com>
On 10/12/21 3:57 AM, Paolo Bonzini wrote:
> 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 guests such as Windows expect all pages to be in
> uninitialized state on startup, including after every guest reboot.
>
> Some userspace implementations of virtual SGX would rather avoid having
> to close and reopen the /dev/sgx_vepc file descriptor and re-mmap the
> virtual EPC. For example, they could sandbox themselves after the guest
> starts and forbid further calls to open(), in order to mitigate exploits
> from untrusted guests.
>
> Therefore, add a ioctl that does this with EREMOVE. Userspace can
> invoke the ioctl to bring its vEPC pages back to uninitialized state.
> There is a possibility that some pages fail to be removed if they are
> SECS pages, and the child and SECS pages could be in separate vEPC
> regions. Therefore, the ioctl returns the number of EREMOVE failures,
> telling userspace to try the ioctl again after it's done with all
> vEPC regions. A more verbose description of the correct usage and
> the possible error conditions is documented in sgx.rst.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The new approach and revised changelogs look fine to me:
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Like Jarkko mentioned, it would be _nice_ to have some self-contained
selftests around this. Would it be a pain to rig something up in
selftests/kvm that at least trivially poked at /dev/sgx_vepc?
next prev parent reply other threads:[~2021-10-14 22:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 10:57 [PATCH v2 0/2] x86: sgx_vepc: implement ioctl to EREMOVE all pages Paolo Bonzini
2021-10-12 10:57 ` [PATCH v2 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page Paolo Bonzini
2021-10-12 16:53 ` Jarkko Sakkinen
2021-10-13 12:56 ` [tip: x86/sgx] x86/sgx/virt: Extract sgx_vepc_remove_page() tip-bot2 for Paolo Bonzini
2021-10-14 22:10 ` [PATCH v2 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page Dave Hansen
2021-10-12 10:57 ` [PATCH v2 2/2] x86: sgx_vepc: implement SGX_IOC_VEPC_REMOVE ioctl Paolo Bonzini
2021-10-12 16:57 ` Jarkko Sakkinen
2021-10-12 17:03 ` Paolo Bonzini
2021-10-12 17:43 ` Jarkko Sakkinen
2021-10-13 12:56 ` [tip: x86/sgx] x86/sgx/virt: Implement " tip-bot2 for Paolo Bonzini
2021-10-14 22:14 ` Dave Hansen [this message]
2021-10-15 22:29 ` [PATCH v2 2/2] x86: sgx_vepc: implement " Sean Christopherson
2021-10-16 7:14 ` Paolo Bonzini
2021-10-13 6:54 ` [PATCH v2 0/2] x86: sgx_vepc: implement ioctl to EREMOVE all pages Borislav Petkov
2021-10-13 7:15 ` Paolo Bonzini
2021-10-13 7:38 ` Borislav Petkov
2021-10-14 12:21 ` Yang Zhong
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