From: Peter Gonda <pgonda@google.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-coco@lists.linux.dev,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Erdem Aktas <erdemaktas@google.com>,
peterz@infradead.org, linux-kernel@vger.kernel.org,
x86@kernel.org, dave.hansen@linux.intel.com
Subject: Re: [PATCH v4 6/6] virt: tdx-guest: Add Quote generation support using TSM_REPORTS
Date: Wed, 27 Sep 2023 10:14:39 -0600 [thread overview]
Message-ID: <CAMkAt6r2VPPMZ__SQfJse8qWsUyYW3AgYbOUVM0S_Vtk=KvkxQ@mail.gmail.com> (raw)
In-Reply-To: <169570185411.596431.3153227201984845022.stgit@dwillia2-xfh.jf.intel.com>
On Mon, Sep 25, 2023 at 10:17 PM Dan Williams <dan.j.williams@intel.com> wrote:
>
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>
> In TDX guest, the attestation process is used to verify the TDX guest
> trustworthiness to other entities before provisioning secrets to the
> guest. The first step in the attestation process is TDREPORT
> generation, which involves getting the guest measurement data in the
> format of TDREPORT, which is further used to validate the authenticity
> of the TDX guest. TDREPORT by design is integrity-protected and can
> only be verified on the local machine.
>
> To support remote verification of the TDREPORT in a SGX-based
> attestation, the TDREPORT needs to be sent to the SGX Quoting Enclave
> (QE) to convert it to a remotely verifiable Quote. SGX QE by design can
> only run outside of the TDX guest (i.e. in a host process or in a
> normal VM) and guest can use communication channels like vsock or
> TCP/IP to send the TDREPORT to the QE. But for security concerns, the
> TDX guest may not support these communication channels. To handle such
> cases, TDX defines a GetQuote hypercall which can be used by the guest
> to request the host VMM to communicate with the SGX QE. More details
> about GetQuote hypercall can be found in TDX Guest-Host Communication
> Interface (GHCI) for Intel TDX 1.0, section titled
> "TDG.VP.VMCALL<GetQuote>".
>
> Trusted Security Module (TSM) [1] exposes a common ABI for Confidential
> Computing Guest platforms to get the measurement data via ConfigFS.
> Extend the TSM framework and add support to allow an attestation agent
> to get the TDX Quote data (included usage example below).
>
> report=/sys/kernel/config/tsm/report/report0
> mkdir $report
> dd if=/dev/urandom bs=64 count=1 > $report/inblob
> hexdump -C $report/outblob
> rmdir $report
>
> GetQuote TDVMCALL requires TD guest pass a 4K aligned shared buffer
> with TDREPORT data as input, which is further used by the VMM to copy
> the TD Quote result after successful Quote generation. To create the
> shared buffer, allocate a large enough memory and mark it shared using
> set_memory_decrypted() in tdx_guest_init(). This buffer will be re-used
> for GetQuote requests in the TDX TSM handler.
>
> Although this method reserves a fixed chunk of memory for GetQuote
> requests, such one time allocation can help avoid memory fragmentation
> related allocation failures later in the uptime of the guest.
>
> Since the Quote generation process is not time-critical or frequently
> used, the current version uses a polling model for Quote requests and
> it also does not support parallel GetQuote requests.
>
> Link: https://lore.kernel.org/lkml/169342399185.3934343.3035845348326944519.stgit@dwillia2-xfh.jf.intel.com/ [1]
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Reviewed-by: Erdem Aktas <erdemaktas@google.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Hey Dan,
I tried running your test commands on an SNP enabled guest. To build
the kernel I just checked out linus/master and applied your series. I
haven't done any debugging yet, so I will update with what I find.
root@Ubuntu2004:~# hexdump -C $report/outblob
[ 219.871875] ------------[ cut here ]------------
[ 219.876642] kernel BUG at include/linux/scatterlist.h:187!
[ 219.882280] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 219.887628] CPU: 0 PID: 1317 Comm: hexdump Not tainted 6.6.0-rc3-xfstests-000
44-gf636850ddfc7 #1
[ 219.896530] Hardware name: Google Google Compute Engine/Google Compute Engine
, BIOS Google 09/26/2023
[ 219.905859] RIP: 0010:enc_dec_message+0x4ed/0x570
[ 219.910673] Code: c7 c0 00 00 00 80 48 2b 05 b8 4f 99 00 e9 dc fd ff ff 0f 0b
bb f4 ff ff ff eb b5 0f 0b 0f 0b 0f 0b e8 e7 47 ce ff 89 c3 eb 94 <0f> 0b 0f 0b
0f 0b 0f 0b 48 8d 7c 24 38 e8 11 6b 23 00 8b 5c 24 58
[ 219.929547] RSP: 0018:ffffc90000e27a18 EFLAGS: 00010246
[ 219.934893] RAX: 0000000000000000 RBX: ffffc90000e27bf8 RCX: 0000000000081000
[ 219.942134] RDX: 0000000000000000 RSI: 0000000000080000 RDI: ffffc90080e27bf8
[ 219.949378] RBP: ffff8881018980a0 R08: 0000000000000000 R09: ffffc90000e27a78
[ 219.956621] R10: 0000000000026680 R11: 0000000000000008 R12: ffff888111a3c400
[ 219.963864] R13: ffff8881018980d0 R14: ffff8881003e7000 R15: 0000000000000060
[ 219.971106] FS: 00007fd7e75f5740(0000) GS:ffff888237c00000(0000) knlGS:00000
00000000000
[ 219.979303] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 219.985160] CR2: 00005563500e8808 CR3: 0008000111986001 CR4: 0000000000370ef0
[ 219.992401] Call Trace:
[ 219.994955] <TASK>
[ 219.997160] ? die+0x36/0x80
[ 220.000149] ? do_trap+0xf4/0x100
[ 220.003574] ? enc_dec_message+0x4ed/0x570
[ 220.007777] ? do_error_trap+0x65/0x80
[ 220.011632] ? enc_dec_message+0x4ed/0x570
[ 220.015842] ? exc_invalid_op+0x50/0x70
[ 220.019788] ? enc_dec_message+0x4ed/0x570
[ 220.023994] ? asm_exc_invalid_op+0x1a/0x20
[ 220.028288] ? enc_dec_message+0x4ed/0x570
[ 220.032505] ? enc_dec_message+0x16f/0x570
[ 220.036711] ? srso_alias_return_thunk+0x5/0x7f
[ 220.041352] ? srso_alias_return_thunk+0x5/0x7f
[ 220.045994] handle_guest_request+0xc6/0x330
[ 220.050375] get_ext_report+0x1e0/0x3d0
[ 220.054323] sev_report_new+0x159/0x460
[ 220.058267] tsm_report_read.part.0+0x96/0x120
[ 220.062818] configfs_bin_read_iter+0xe1/0x1e0
[ 220.067377] vfs_read+0x1db/0x310
[ 220.070813] ksys_read+0x6f/0xf0
[ 220.074152] do_syscall_64+0x3f/0x90
[ 220.077843] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[ 220.083007] RIP: 0033:0x7fd7e7705fd2
[ 220.086695] Code: c0 e9 c2 fe ff ff 50 48 8d 3d aa cb 0a 00 e8 d5 1a 02 00 0f
1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0
ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
[ 220.105572] RSP: 002b:00007fff9bc8fc18 EFLAGS: 00000246 ORIG_RAX: 00000000000
00000
[ 220.113252] RAX: ffffffffffffffda RBX: 00007fd7e77e4980 RCX: 00007fd7e7705fd2
[ 220.120496] RDX: 0000000000001000 RSI: 00005563500e7800 RDI: 0000000000000000
[ 220.127742] RBP: 00007fd7e77e14a0 R08: 0000000000000000 R09: 000000000000007c
[ 220.134988] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010
[ 220.142232] R13: 00007fd7e77e08a0 R14: 0000000000000d68 R15: 0000000000000d68
[ 220.149479] </TASK>
[ 220.151865] ---[ end trace 0000000000000000 ]---
[ 220.156629] RIP: 0010:enc_dec_message+0x4ed/0x570
[ 220.161479] Code: c7 c0 00 00 00 80 48 2b 05 b8 4f 99 00 e9 dc fd ff ff 0f 0b
bb f4 ff ff ff eb b5 0f 0b 0f 0b 0f 0b e8 e7 47 ce ff 89 c3 eb 94 <0f> 0b 0f 0b
0f 0b 0f 0b 48 8d 7c 24 38 e8 11 6b 23 00 8b 5c 24 58
[ 220.180379] RSP: 0018:ffffc90000e27a18 EFLAGS: 00010246
[ 220.185743] RAX: 0000000000000000 RBX: ffffc90000e27bf8 RCX: 0000000000081000
[ 220.193012] RDX: 0000000000000000 RSI: 0000000000080000 RDI: ffffc90080e27bf8
[ 220.200280] RBP: ffff8881018980a0 R08: 0000000000000000 R09: ffffc90000e27a78
[ 220.207551] R10: 0000000000026680 R11: 0000000000000008 R12: ffff888111a3c400
[ 220.214822] R13: ffff8881018980d0 R14: ffff8881003e7000 R15: 0000000000000060
[ 220.222094] FS: 00007fd7e75f5740(0000) GS:ffff888237c00000(0000) knlGS:00000
00000000000
[ 220.230329] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 220.236210] CR2: 00005563500e8808 CR3: 0008000111986001 CR4: 0000000000370ef0
next prev parent reply other threads:[~2023-09-27 16:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 4:16 [PATCH v4 0/6] configfs-tsm: Attestation Report ABI Dan Williams
2023-09-26 4:17 ` [PATCH v4 1/6] virt: coco: Add a coco/Makefile and coco/Kconfig Dan Williams
2023-09-26 4:17 ` [PATCH v4 2/6] configfs-tsm: Introduce a shared ABI for attestation reports Dan Williams
2023-09-26 18:49 ` Kuppuswamy Sathyanarayanan
2023-09-26 18:59 ` Dan Williams
2023-09-27 0:43 ` Kuppuswamy Sathyanarayanan
2023-09-27 3:17 ` Dan Williams
2023-09-27 8:04 ` Thomas Fossati
2023-09-27 8:21 ` Dan Williams
2023-09-27 8:25 ` Thomas Fossati
2023-09-27 14:38 ` Peter Gonda
2023-09-27 19:05 ` Thomas Fossati
2023-09-27 8:43 ` Thomas Fossati
2023-09-27 2:10 ` Kuppuswamy Sathyanarayanan
2023-09-26 4:17 ` [PATCH v4 3/6] virt: sevguest: Prep for kernel internal {get, get_ext}_report() Dan Williams
2023-09-26 18:51 ` Kuppuswamy Sathyanarayanan
2023-09-26 4:17 ` [PATCH v4 4/6] mm/slab: Add __free() support for kvfree Dan Williams
2023-09-26 4:17 ` [PATCH v4 5/6] virt: sevguest: Add TSM_REPORTS support for SNP_{GET, GET_EXT}_REPORT Dan Williams
2023-10-04 8:22 ` Dan Carpenter
2023-09-26 4:17 ` [PATCH v4 6/6] virt: tdx-guest: Add Quote generation support using TSM_REPORTS Dan Williams
2023-09-27 16:14 ` Peter Gonda [this message]
2023-09-27 16:53 ` Dan Williams
2023-09-28 22:49 ` Dan Williams
2023-09-29 17:26 ` Peter Gonda
2023-10-03 18:37 ` Peter Gonda
2023-10-03 19:29 ` Kuppuswamy Sathyanarayanan
2023-10-03 20:06 ` Peter Gonda
2023-10-04 0:54 ` Dan Williams
2023-10-10 19:36 ` Dan Williams
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