Re: [PATCH v6 18/60] i386/tdvf: Introduce function to parse TDVF metadata

Daniel P. Berrangé
2024-11-05T10:43:06Z

On Tue, Nov 05, 2024 at 01:23:26AM -0500, Xiaoyao Li wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
>
> TDX VM needs to boot with its specialized firmware, Trusted Domain
> Virtual Firmware (TDVF). QEMU needs to parse TDVF and map it in TD
> guest memory prior to running the TDX VM.
>
> A TDVF Metadata in TDVF image describes the structure of firmware.
> QEMU refers to it to setup memory for TDVF. Introduce function
> tdvf_parse_metadata() to parse the metadata from TDVF image and store
> the info of each TDVF section.
>
> TDX metadata is located by a TDX metadata offset block, which is a
> GUID-ed structure. The data portion of the GUID structure contains
> only an 4-byte field that is the offset of TDX metadata to the end
> of firmware file.
>
> Select X86_FW_OVMF when TDX is enable to leverage existing functions
> to parse and search OVMF's GUID-ed structures.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
> Changes in v6:
> - Drop the the data endianness change for metadata->Length;
>
> Changes in v1:
> - rename tdvf_parse_section_entry() to
> tdvf_parse_and_check_section_entry()
>
> Changes in RFC v4:
> - rename TDX_METADATA_GUID to TDX_METADATA_OFFSET_GUID
> ---
> hw/i386/Kconfig | 1 +
> hw/i386/meson.build | 1 +
> hw/i386/tdvf.c | 200 +++++++++++++++++++++++++++++++++++++++++
> include/hw/i386/tdvf.h | 51 +++++++++++
> 4 files changed, 253 insertions(+)
> create mode 100644 hw/i386/tdvf.c
> create mode 100644 include/hw/i386/tdvf.h
>
> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
> index 86bc10377c4f..555a000037bc 100644
> --- a/hw/i386/Kconfig
> +++ b/hw/i386/Kconfig
> @@ -12,6 +12,7 @@ config SGX
>
> config TDX
> bool
> + select X86_FW_OVMF
> depends on KVM
>
> config PC
> diff --git a/hw/i386/meson.build b/hw/i386/meson.build
> index 10bdfde27c69..3bc1da2b6eb4 100644
> --- a/hw/i386/meson.build
> +++ b/hw/i386/meson.build
> @@ -32,6 +32,7 @@ i386_ss.add(when: 'CONFIG_PC', if_true: files(
> 'port92.c'))
> i386_ss.add(when: 'CONFIG_X86_FW_OVMF', if_true: files('pc_sysfw_ovmf.c'),
> if_false: files('pc_sysfw_ovmf-stubs.c'))
> +i386_ss.add(when: 'CONFIG_TDX', if_true: files('tdvf.c'))
>
> subdir('kvm')
> subdir('xen')
> diff --git a/hw/i386/tdvf.c b/hw/i386/tdvf.c
> new file mode 100644
> index 000000000000..4afa636bfa0e
> --- /dev/null
> +++ b/hw/i386/tdvf.c
> @@ -0,0 +1,200 @@
> +/*
> + * SPDX-License-Identifier: GPL-2.0-or-later

Since you have this SPDX tag....

> +
> + * Copyright (c) 2020 Intel Corporation
> + * Author: Isaku Yamahata <isaku.yamahata at gmail.com>
> + * <isaku.yamahata at intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> +
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> +
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.

...you should omit the GPL boilerplate text here, as the new
QEMU standard is to use only SPDX for new files.

> +
> +int tdvf_parse_metadata(TdxFirmware *fw, void *flash_ptr, int size)
> +{
> + TdvfSectionEntry *sections;

g_autofree TdvfSectionEntry *sections = NULL;

will avoid the duplicated 'g_free' calls later

> + TdvfMetadata *metadata;
> + ssize_t entries_size;
> + int i;
> +
> + metadata = tdvf_get_metadata(flash_ptr, size);
> + if (!metadata) {
> + return -EINVAL;
> + }
> +
> + /* load and parse metadata entries */
> + fw->nr_entries = le32_to_cpu(metadata->NumberOfSectionEntries);
> + if (fw->nr_entries < 2) {
> + error_report("Invalid number of fw entries (%u) in TDVF Metadata",
> + fw->nr_entries);
> + return -EINVAL;
> + }
> +
> + entries_size = fw->nr_entries * sizeof(TdvfSectionEntry);
> + if (metadata->Length != sizeof(*metadata) + entries_size) {
> + error_report("TDVF metadata len (0x%x) mismatch, expected (0x%x)",
> + metadata->Length,
> + (uint32_t)(sizeof(*metadata) + entries_size));
> + return -EINVAL;
> + }
> +
> + fw->entries = g_new(TdxFirmwareEntry, fw->nr_entries);
> + sections = g_new(TdvfSectionEntry, fw->nr_entries);
> +
> + if (!memcpy(sections, (void *)metadata + sizeof(*metadata), entries_size)) {
> + error_report("Failed to read TDVF section entries");
> + goto err;
> + }
> +
> + for (i = 0; i < fw->nr_entries; i++) {
> + if (tdvf_parse_and_check_section_entry(&sections[i], &fw->entries[i])) {
> + goto err;
> + }
> + }
> + g_free(sections);
> +
> + return 0;
> +
> +err:
> + g_free(sections);
> + fw->entries = 0;
> + g_free(fw->entries);
> + return -EINVAL;
> +}
> diff --git a/include/hw/i386/tdvf.h b/include/hw/i386/tdvf.h
> new file mode 100644
> index 000000000000..593341eb2e93
> --- /dev/null
> +++ b/include/hw/i386/tdvf.h
> @@ -0,0 +1,51 @@
> +/*
> + * SPDX-License-Identifier: GPL-2.0-or-later
> +
> + * Copyright (c) 2020 Intel Corporation
> + * Author: Isaku Yamahata <isaku.yamahata at gmail.com>
> + * <isaku.yamahata at intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> +
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> +
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */

Same note about only using SPDX.

With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|