Re: [PATCH v4 14/15] x86/sev: Extend the config-fs attestation support for an SVSM

From: Borislav Petkov
Date: Fri May 31 2024 - 09:17:41 EST


On Wed, Apr 24, 2024 at 10:58:10AM -0500, Tom Lendacky wrote:
> +/*
> + * The SVSM Attestation related structures
> + */
> +struct svsm_location_entry {

"svsm_loc" should be enough.

> + u64 pa;
> + u32 len;
> + u8 rsvd[4];
> +};
> +
> +struct svsm_attestation_call {

Can we shorten all "attestion" to "atst" or "attest"?

> + struct svsm_location_entry report_buffer;
> + struct svsm_location_entry nonce;
> + struct svsm_location_entry manifest_buffer;
> + struct svsm_location_entry certificates_buffer;

report_buf;
nonce;
manifest_buf;
certs_buf;

Please shorten all those.

> + /* For attesting a single service */
> + u8 service_guid[16];
> + u32 service_manifest_version;

manifest_ver;

> + u8 rsvd[4];
> +};
> +
> /*
> * SVSM protocol structure

..

> +static void update_attestation_input(struct svsm_call *call, struct svsm_attestation_call *input)
> +{
> + /* If (new) lengths have been returned, propograte them up */

"propagate"

> + if (call->rcx_out != call->rcx)
> + input->manifest_buffer.len = call->rcx_out;
> +
> + if (call->rdx_out != call->rdx)
> + input->certificates_buffer.len = call->rdx_out;
> +
> + if (call->r8_out != call->r8)
> + input->report_buffer.len = call->r8_out;
> +}
> +
> +int snp_issue_svsm_attestation_request(u64 call_id, struct svsm_attestation_call *input)

This looks like BIOS code. The only thing that's missing is the
CamelCase. :-)

int snp_issue_svsm_attest_req(u64 call_id, struct svsm_attest_call *input_call)

Now that's more like it!

> +{
> + struct svsm_attestation_call *attest_call;

struct svsm_attest_call *atst_call;

> + struct svsm_call call = {};
> + unsigned long flags;
> + u64 attest_call_pa;
> + int ret;
> +
> + if (!vmpl)
> + return -EINVAL;
> +

..

> +static int sev_svsm_report_new(struct tsm_report *report, void *data)
> +{
> + unsigned int report_len, manifest_len, certificates_len;
> + void *report_blob, *manifest_blob, *certificates_blob;

Prose. Shorter pls.

> + struct svsm_attestation_call attest_call = {};
> + struct tsm_desc *desc = &report->desc;
> + unsigned int retry_count;
> + unsigned int size;
> + bool try_again;
> + void *buffer;
> + u64 call_id;
> + int ret;

..

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette