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Thu, 24 Feb 2022 10:27:52 +0000 (GMT) Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2BAA3124053; Thu, 24 Feb 2022 10:27:49 +0000 (GMT) Received: from [9.160.8.241] (unknown [9.160.8.241]) by b01ledav002.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 24 Feb 2022 10:27:48 +0000 (GMT) Message-ID: <0e1d4cf7-225f-c5ef-bc67-1fe811530ce4@linux.ibm.com> Date: Thu, 24 Feb 2022 12:27:46 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH v2] qapi, target/i386/sev: Add cpu0-id to query-sev-capabilities Content-Language: en-US To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= References: <20220224061405.1959756-1-dovmurik@linux.ibm.com> From: Dov Murik In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 1sNKBUjX3Xhn2FBAy0IYltXvlCrXCuo- X-Proofpoint-ORIG-GUID: yinBGtpprZeD31EhgD9aK7rJxC5O3g91 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-02-24_01,2022-02-24_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 lowpriorityscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 impostorscore=0 spamscore=0 mlxlogscore=999 mlxscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202240060 Received-SPF: pass client-ip=148.163.158.5; envelope-from=dovmurik@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tom Lendacky , Ashish Kalra , Brijesh Singh , Markus Armbruster , James Bottomley , Marcelo Tosatti , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Dov Murik , Tobin Feldman-Fitzthum , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 24/02/2022 10:59, Daniel P. Berrangé wrote: > On Thu, Feb 24, 2022 at 06:14:05AM +0000, Dov Murik wrote: >> Add a new field 'cpu0-id' to the response of query-sev-capabilities QMP >> command. The value of the field is the base64-encoded 64-byte unique ID >> of the CPU0 (socket 0), which can be used to retrieve the signed CEK of >> the CPU from AMD's Key Distribution Service (KDS). >> >> Signed-off-by: Dov Murik >> >> --- >> >> v2: >> - change encoding to Base64 (thanks Daniel) >> - rename constant to SEV_CPU_UNIQUE_ID_LEN >> --- >> qapi/misc-target.json | 4 ++++ >> target/i386/sev.c | 27 +++++++++++++++++++++++++++ >> 2 files changed, 31 insertions(+) >> >> diff --git a/qapi/misc-target.json b/qapi/misc-target.json >> index 4bc45d2474..c6d9ad69e1 100644 >> --- a/qapi/misc-target.json >> +++ b/qapi/misc-target.json >> @@ -177,6 +177,8 @@ >> # >> # @cert-chain: PDH certificate chain (base64 encoded) >> # >> +# @cpu0-id: 64-byte unique ID of CPU0 (base64 encoded) (since 7.0) >> +# >> # @cbitpos: C-bit location in page table entry >> # >> # @reduced-phys-bits: Number of physical Address bit reduction when SEV is >> @@ -187,6 +189,7 @@ >> { 'struct': 'SevCapability', >> 'data': { 'pdh': 'str', >> 'cert-chain': 'str', >> + 'cpu0-id': 'str', >> 'cbitpos': 'int', >> 'reduced-phys-bits': 'int'}, >> 'if': 'TARGET_I386' } >> @@ -205,6 +208,7 @@ >> # >> # -> { "execute": "query-sev-capabilities" } >> # <- { "return": { "pdh": "8CCDD8DDD", "cert-chain": "888CCCDDDEE", >> +# "cpu0-id": "2lvmGwo+...61iEinw==", >> # "cbitpos": 47, "reduced-phys-bits": 5}} >> # >> ## >> diff --git a/target/i386/sev.c b/target/i386/sev.c >> index 025ff7a6f8..d3d2680e16 100644 >> --- a/target/i386/sev.c >> +++ b/target/i386/sev.c >> @@ -82,6 +82,8 @@ struct SevGuestState { >> #define DEFAULT_GUEST_POLICY 0x1 /* disable debug */ >> #define DEFAULT_SEV_DEVICE "/dev/sev" >> >> +#define SEV_CPU_UNIQUE_ID_LEN 64 > > Is this fixed size actually guaranteed by AMD ? In reading the spec > for "GET_ID" it feels like they're intentionally not specifying a > fixed length, pushing towards querying once and then re-trying with > the reported buffer size: > > "If the value of the ID_LEN field is too small, an > INVALID_LENGTH error is returned and the minimum > required length is written to the field" > > I didn't find where it says 64 bytes exactly. > OK. I'll change it to dynamically allocate the ID buffer based on the length returned by the first query, similar to sev_get_pdh_info(). I'll remove the explicit lengths from the qapi description and the commit message. -Dov >> + >> #define SEV_INFO_BLOCK_GUID "00f771de-1a7e-4fcb-890e-68c77e2fb44e" >> typedef struct __attribute__((__packed__)) SevInfoBlock { >> /* SEV-ES Reset Vector Address */ >> @@ -531,11 +533,31 @@ e_free: >> return 1; >> } >> >> +static int >> +sev_get_id(int fd, guchar *id_buf, size_t id_buf_len, Error **errp) >> +{ >> + struct sev_user_data_get_id2 id = { >> + .address = (unsigned long)id_buf, >> + .length = id_buf_len >> + }; >> + int err, r; >> + >> + r = sev_platform_ioctl(fd, SEV_GET_ID2, &id, &err); >> + if (r < 0) { >> + error_setg(errp, "SEV: Failed to get ID ret=%d fw_err=%d (%s)", >> + r, err, fw_error_to_str(err)); >> + return 1; >> + } >> + >> + return 0; >> +} >> + >> static SevCapability *sev_get_capabilities(Error **errp) >> { >> SevCapability *cap = NULL; >> guchar *pdh_data = NULL; >> guchar *cert_chain_data = NULL; >> + guchar cpu0_id[SEV_CPU_UNIQUE_ID_LEN]; >> size_t pdh_len = 0, cert_chain_len = 0; >> uint32_t ebx; >> int fd; >> @@ -561,9 +583,14 @@ static SevCapability *sev_get_capabilities(Error **errp) >> goto out; >> } >> >> + if (sev_get_id(fd, cpu0_id, sizeof(cpu0_id), errp)) { >> + goto out; >> + } >> + >> cap = g_new0(SevCapability, 1); >> cap->pdh = g_base64_encode(pdh_data, pdh_len); >> cap->cert_chain = g_base64_encode(cert_chain_data, cert_chain_len); >> + cap->cpu0_id = g_base64_encode(cpu0_id, sizeof(cpu0_id)); >> >> host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL); >> cap->cbitpos = ebx & 0x3f; >> -- >> 2.25.1 >> > > Regards, > Daniel