Re: [PATCH Part1 RFC v4 20/36] x86/sev: Use SEV-SNP AP creation to start secondary CPUs

Borislav Petkov
2021-08-17T20:03:50Z

On Wed, Jul 07, 2021 at 01:14:50PM -0500, Brijesh Singh wrote:
> @@ -854,6 +858,207 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages)
> pvalidate_pages(vaddr, npages, 1);
> }
>
> +static int vmsa_rmpadjust(void *va, bool vmsa)

I know, I know it gets a bool vmsa param but you can still call it
simply rmpadjust() because this is what it does - it is a wrapper around
the insn. Just like pvalidate() and so on.

...

> +static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
> +{
> + struct sev_es_save_area *cur_vmsa, *vmsa;
> + struct ghcb_state state;
> + unsigned long flags;
> + struct ghcb *ghcb;
> + int cpu, err, ret;
> + u8 sipi_vector;
> + u64 cr4;
> +
> + if ((sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION) != GHCB_HV_FT_SNP_AP_CREATION)
> + return -EOPNOTSUPP;
> +
> + /*
> + * Verify the desired start IP against the known trampoline start IP
> + * to catch any future new trampolines that may be introduced that
> + * would require a new protected guest entry point.
> + */
> + if (WARN_ONCE(start_ip != real_mode_header->trampoline_start,
> + "unsupported SEV-SNP start_ip: %lx\n", start_ip))

"Unsupported... " - with a capital letter

> + return -EINVAL;
> +
> + /* Override start_ip with known protected guest start IP */
> + start_ip = real_mode_header->sev_es_trampoline_start;
> +

...

--
Regards/Gruss,
Boris.