Re: [PATCH v4 5/6] virt: sevguest: Add TSM_REPORTS support for SNP_{GET, GET_EXT}_REPORT

From: Dan Carpenter
Date: Wed Oct 04 2023 - 04:22:54 EST


Hi Dan,

kernel test robot noticed the following build warnings:

url: https://github.com/intel-lab-lkp/linux/commits/Dan-Williams/virt-coco-Add-a-coco-Makefile-and-coco-Kconfig/20230926-121843
base: 6465e260f48790807eef06b583b38ca9789b6072
patch link: https://lore.kernel.org/r/169570184829.596431.15991881056638719011.stgit%40dwillia2-xfh.jf.intel.com
patch subject: [PATCH v4 5/6] virt: sevguest: Add TSM_REPORTS support for SNP_{GET, GET_EXT}_REPORT
config: x86_64-randconfig-161-20231002 (https://download.01.org/0day-ci/archive/20231003/202310030341.zaOu0ew0-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20231003/202310030341.zaOu0ew0-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202310030341.zaOu0ew0-lkp@xxxxxxxxx/

smatch warnings:
drivers/virt/coco/sev-guest/sev-guest.c:853 sev_report_new() error: uninitialized symbol 'certs_size'.

vim +/certs_size +853 drivers/virt/coco/sev-guest/sev-guest.c

80013405d5b7c6 Dan Williams 2023-09-25 778 static int sev_report_new(struct tsm_report *report, void *data)
80013405d5b7c6 Dan Williams 2023-09-25 779 {
80013405d5b7c6 Dan Williams 2023-09-25 780 static const struct snp_msg_cert_entry zero_ent = { 0 };
80013405d5b7c6 Dan Williams 2023-09-25 781 struct tsm_desc *desc = &report->desc;
80013405d5b7c6 Dan Williams 2023-09-25 782 struct snp_guest_dev *snp_dev = data;
80013405d5b7c6 Dan Williams 2023-09-25 783 struct snp_msg_report_resp_hdr hdr;
80013405d5b7c6 Dan Williams 2023-09-25 784 const int report_size = SZ_4K;
80013405d5b7c6 Dan Williams 2023-09-25 785 const int ext_size = SZ_16K;
80013405d5b7c6 Dan Williams 2023-09-25 786 int ret, size = report_size + ext_size;
80013405d5b7c6 Dan Williams 2023-09-25 787 int certs_size, cert_count, i, offset;
80013405d5b7c6 Dan Williams 2023-09-25 788 u8 *certs_address;
80013405d5b7c6 Dan Williams 2023-09-25 789
80013405d5b7c6 Dan Williams 2023-09-25 790 if (desc->inblob_len != 64)
80013405d5b7c6 Dan Williams 2023-09-25 791 return -EINVAL;
80013405d5b7c6 Dan Williams 2023-09-25 792
80013405d5b7c6 Dan Williams 2023-09-25 793 void *buf __free(kvfree) = kvzalloc(size, GFP_KERNEL);
80013405d5b7c6 Dan Williams 2023-09-25 794 if (!buf)
80013405d5b7c6 Dan Williams 2023-09-25 795 return -ENOMEM;
80013405d5b7c6 Dan Williams 2023-09-25 796
80013405d5b7c6 Dan Williams 2023-09-25 797 guard(mutex)(&snp_cmd_mutex);

Hoho. Need guard stuff and no warnings generated. Perhaps I have added
all the new unlock functions. :)

80013405d5b7c6 Dan Williams 2023-09-25 798 certs_address = buf + report_size;
80013405d5b7c6 Dan Williams 2023-09-25 799 struct snp_ext_report_req ext_req = {
80013405d5b7c6 Dan Williams 2023-09-25 800 .data = { .vmpl = desc->privlevel },
80013405d5b7c6 Dan Williams 2023-09-25 801 .certs_address = (__u64)certs_address,
80013405d5b7c6 Dan Williams 2023-09-25 802 .certs_len = ext_size,
80013405d5b7c6 Dan Williams 2023-09-25 803 };
80013405d5b7c6 Dan Williams 2023-09-25 804 memcpy(&ext_req.data.user_data, desc->inblob, desc->inblob_len);
80013405d5b7c6 Dan Williams 2023-09-25 805
80013405d5b7c6 Dan Williams 2023-09-25 806 struct snp_guest_request_ioctl input = {
80013405d5b7c6 Dan Williams 2023-09-25 807 .msg_version = 1,
80013405d5b7c6 Dan Williams 2023-09-25 808 .req_data = (__u64)&ext_req,
80013405d5b7c6 Dan Williams 2023-09-25 809 .resp_data = (__u64)buf,
80013405d5b7c6 Dan Williams 2023-09-25 810 };
80013405d5b7c6 Dan Williams 2023-09-25 811 struct snp_req_resp io = {
80013405d5b7c6 Dan Williams 2023-09-25 812 .req_data = KERNEL_SOCKPTR(&ext_req),
80013405d5b7c6 Dan Williams 2023-09-25 813 .resp_data = KERNEL_SOCKPTR(buf),
80013405d5b7c6 Dan Williams 2023-09-25 814 };
80013405d5b7c6 Dan Williams 2023-09-25 815
80013405d5b7c6 Dan Williams 2023-09-25 816 ret = get_ext_report(snp_dev, &input, &io);
80013405d5b7c6 Dan Williams 2023-09-25 817
80013405d5b7c6 Dan Williams 2023-09-25 818 if (ret)
80013405d5b7c6 Dan Williams 2023-09-25 819 return ret;
80013405d5b7c6 Dan Williams 2023-09-25 820
80013405d5b7c6 Dan Williams 2023-09-25 821 memcpy(&hdr, buf, sizeof(hdr));
80013405d5b7c6 Dan Williams 2023-09-25 822 if (hdr.status == SNP_REPORT_INVALID_PARAM)
80013405d5b7c6 Dan Williams 2023-09-25 823 return -EINVAL;
80013405d5b7c6 Dan Williams 2023-09-25 824 if (hdr.status == SNP_REPORT_INVALID_KEY_SEL)
80013405d5b7c6 Dan Williams 2023-09-25 825 return -EINVAL;
80013405d5b7c6 Dan Williams 2023-09-25 826 if (hdr.status)
80013405d5b7c6 Dan Williams 2023-09-25 827 return -ENXIO;
80013405d5b7c6 Dan Williams 2023-09-25 828 if ((hdr.report_size + sizeof(hdr)) > report_size)
80013405d5b7c6 Dan Williams 2023-09-25 829 return -ENOMEM;
80013405d5b7c6 Dan Williams 2023-09-25 830
80013405d5b7c6 Dan Williams 2023-09-25 831 void *rbuf __free(kvfree) = kvzalloc(hdr.report_size, GFP_KERNEL);
80013405d5b7c6 Dan Williams 2023-09-25 832 if (!rbuf)
80013405d5b7c6 Dan Williams 2023-09-25 833 return -ENOMEM;
80013405d5b7c6 Dan Williams 2023-09-25 834
80013405d5b7c6 Dan Williams 2023-09-25 835 memcpy(rbuf, buf + sizeof(hdr), hdr.report_size);
80013405d5b7c6 Dan Williams 2023-09-25 836 report->outblob = no_free_ptr(rbuf);
80013405d5b7c6 Dan Williams 2023-09-25 837 report->outblob_len = hdr.report_size;
80013405d5b7c6 Dan Williams 2023-09-25 838
80013405d5b7c6 Dan Williams 2023-09-25 839 for (i = 0; i < ext_size / sizeof(struct snp_msg_cert_entry); i++) {
80013405d5b7c6 Dan Williams 2023-09-25 840 struct snp_msg_cert_entry *certs = buf + report_size;
80013405d5b7c6 Dan Williams 2023-09-25 841
80013405d5b7c6 Dan Williams 2023-09-25 842 if (memcmp(&certs[i], &zero_ent, sizeof(zero_ent)) == 0)
80013405d5b7c6 Dan Williams 2023-09-25 843 break;
80013405d5b7c6 Dan Williams 2023-09-25 844 certs_size += certs[i].length;

certs_size needs to be initialized to zero.

80013405d5b7c6 Dan Williams 2023-09-25 845 }
80013405d5b7c6 Dan Williams 2023-09-25 846 cert_count = i;
80013405d5b7c6 Dan Williams 2023-09-25 847
80013405d5b7c6 Dan Williams 2023-09-25 848 /* No certs to report */
80013405d5b7c6 Dan Williams 2023-09-25 849 if (cert_count == 0)
80013405d5b7c6 Dan Williams 2023-09-25 850 return 0;
80013405d5b7c6 Dan Williams 2023-09-25 851
80013405d5b7c6 Dan Williams 2023-09-25 852 /* sanity check that the entire certs table with metadata fits */
80013405d5b7c6 Dan Williams 2023-09-25 @853 if ((cert_count + 1) * sizeof(zero_ent) + certs_size > ext_size)
80013405d5b7c6 Dan Williams 2023-09-25 854 return -ENXIO;
80013405d5b7c6 Dan Williams 2023-09-25 855
80013405d5b7c6 Dan Williams 2023-09-25 856 void *cbuf __free(kvfree) = kvzalloc(certs_size, GFP_KERNEL);
80013405d5b7c6 Dan Williams 2023-09-25 857 if (!cbuf)
80013405d5b7c6 Dan Williams 2023-09-25 858 return -ENOMEM;
80013405d5b7c6 Dan Williams 2023-09-25 859
80013405d5b7c6 Dan Williams 2023-09-25 860 /* Concatenate returned certs */
80013405d5b7c6 Dan Williams 2023-09-25 861 for (i = 0, offset = 0; i < cert_count; i++) {
80013405d5b7c6 Dan Williams 2023-09-25 862 struct snp_msg_cert_entry *certs = buf + report_size;
80013405d5b7c6 Dan Williams 2023-09-25 863
80013405d5b7c6 Dan Williams 2023-09-25 864 memcpy(cbuf + offset, certs_address + certs[i].offset, certs[i].length);
80013405d5b7c6 Dan Williams 2023-09-25 865 offset += certs[i].length;
80013405d5b7c6 Dan Williams 2023-09-25 866 }
80013405d5b7c6 Dan Williams 2023-09-25 867
80013405d5b7c6 Dan Williams 2023-09-25 868 report->certs = no_free_ptr(cbuf);
80013405d5b7c6 Dan Williams 2023-09-25 869 report->certs_len = certs_size;
80013405d5b7c6 Dan Williams 2023-09-25 870
80013405d5b7c6 Dan Williams 2023-09-25 871 return 0;
80013405d5b7c6 Dan Williams 2023-09-25 872 }

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https://github.com/intel/lkp-tests/wiki