Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C
From:   Michael Roth <michael.roth@amd.com>
To:     <kvm@vger.kernel.org>
CC:     <linux-coco@lists.linux.dev>, <linux-mm@kvack.org>,
        <linux-crypto@vger.kernel.org>, <x86@kernel.org>,
        <linux-kernel@vger.kernel.org>, <tglx@linutronix.de>,
        <mingo@redhat.com>, <jroedel@suse.de>, <thomas.lendacky@amd.com>,
        <hpa@zytor.com>, <ardb@kernel.org>, <pbonzini@redhat.com>,
        <seanjc@google.com>, <vkuznets@redhat.com>, <jmattson@google.com>,
        <luto@kernel.org>, <dave.hansen@linux.intel.com>, <slp@redhat.com>,
        <pgonda@google.com>, <peterz@infradead.org>,
        <srinivas.pandruvada@linux.intel.com>, <rientjes@google.com>,
        <dovmurik@linux.ibm.com>, <tobin@ibm.com>, <bp@alien8.de>,
        <vbabka@suse.cz>, <kirill@shutemov.name>, <ak@linux.intel.com>,
        <tony.luck@intel.com>, <marcorr@google.com>,
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        <alpergun@google.com>, <dgilbert@redhat.com>, <jarkko@kernel.org>,
        <ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
        Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH RFC v8 28/56] crypto: ccp: Provide APIs to query extended attestation report
Date:   Mon, 20 Feb 2023 12:38:19 -0600
Message-ID: <20230220183847.59159-29-michael.roth@amd.com>
In-Reply-To: <20230220183847.59159-1-michael.roth@amd.com>
References: <20230220183847.59159-1-michael.roth@amd.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2023 18:50:32.4905
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: f23e4168-cfca-4023-1009-08db1373583e
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource: DM6NAM11FT037.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ1PR12MB6362
Precedence: bulk
List-ID: <linux-crypto.vger.kernel.org>
X-Mailing-List: linux-crypto@vger.kernel.org

From: Brijesh Singh <brijesh.singh@amd.com>

Version 2 of the GHCB specification defines VMGEXIT that is used to get
the extended attestation report. The extended attestation report includes
the certificate blobs provided through the SNP_SET_EXT_CONFIG.

The snp_guest_ext_guest_request() will be used by the hypervisor to get
the extended attestation report. See the GHCB specification for more
details.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 drivers/crypto/ccp/sev-dev.c | 47 ++++++++++++++++++++++++++++++++++++
 include/linux/psp-sev.h      | 33 +++++++++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index b56b00ca2cd4..e65563bc8298 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -2017,6 +2017,53 @@ int sev_guest_df_flush(int *error)
 }
 EXPORT_SYMBOL_GPL(sev_guest_df_flush);
 
+int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data,
+				unsigned long vaddr, unsigned long *npages, unsigned long *fw_err)
+{
+	unsigned long expected_npages;
+	struct sev_device *sev;
+	int rc;
+
+	if (!psp_master || !psp_master->sev_data)
+		return -ENODEV;
+
+	sev = psp_master->sev_data;
+
+	if (!sev->snp_initialized)
+		return -EINVAL;
+
+	mutex_lock(&sev->snp_certs_lock);
+	/*
+	 * Check if there is enough space to copy the certificate chain. Otherwise
+	 * return ERROR code defined in the GHCB specification.
+	 */
+	expected_npages = sev->snp_certs_len >> PAGE_SHIFT;
+	if (*npages < expected_npages) {
+		*npages = expected_npages;
+		*fw_err = SNP_GUEST_REQ_INVALID_LEN;
+		mutex_unlock(&sev->snp_certs_lock);
+		return -EINVAL;
+	}
+
+	rc = sev_do_cmd(SEV_CMD_SNP_GUEST_REQUEST, data, (int *)fw_err);
+	if (rc) {
+		mutex_unlock(&sev->snp_certs_lock);
+		return rc;
+	}
+
+	/* Copy the certificate blob */
+	if (sev->snp_certs_data) {
+		*npages = expected_npages;
+		memcpy((void *)vaddr, sev->snp_certs_data, *npages << PAGE_SHIFT);
+	} else {
+		*npages = 0;
+	}
+
+	mutex_unlock(&sev->snp_certs_lock);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(snp_guest_ext_guest_request);
+
 static void sev_exit(struct kref *ref)
 {
 	misc_deregister(&misc_dev->misc);
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index d19744807471..81bafc049eca 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -931,6 +931,32 @@ void snp_free_firmware_page(void *addr);
  */
 void snp_mark_pages_offline(unsigned long pfn, unsigned int npages);
 
+/**
+ * snp_guest_ext_guest_request - perform the SNP extended guest request command
+ *  defined in the GHCB specification.
+ *
+ * @data: the input guest request structure
+ * @vaddr: address where the certificate blob need to be copied.
+ * @npages: number of pages for the certificate blob.
+ *    If the specified page count is less than the certificate blob size, then the
+ *    required page count is returned with error code defined in the GHCB spec.
+ *    If the specified page count is more than the certificate blob size, then
+ *    page count is updated to reflect the amount of valid data copied in the
+ *    vaddr.
+ *
+ * @sev_ret: sev command return code
+ *
+ * Returns:
+ * 0 if the sev successfully processed the command
+ * -%ENODEV    if the sev device is not available
+ * -%ENOTSUPP  if the sev does not support SEV
+ * -%ETIMEDOUT if the sev command timed out
+ * -%EIO       if the sev returned a non-zero return code
+ */
+int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data,
+				unsigned long vaddr, unsigned long *npages,
+				unsigned long *error);
+
 #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
 
 static inline int
@@ -968,6 +994,13 @@ static inline void *snp_alloc_firmware_page(gfp_t mask)
 
 static inline void snp_free_firmware_page(void *addr) { }
 
+static inline int snp_guest_ext_guest_request(struct sev_data_snp_guest_request *data,
+					      unsigned long vaddr, unsigned long *n,
+					      unsigned long *error)
+{
+	return -ENODEV;
+}
+
 #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
 
 #endif	/* __PSP_SEV_H__ */
-- 
2.25.1