arch/x86/coco/sev/noinstr.c

Source file repositories/reference/linux-study-clean/arch/x86/coco/sev/noinstr.c

File Facts

System
Linux kernel
Corpus path
arch/x86/coco/sev/noinstr.c
Extension
.c
Size
4718 bytes
Lines
192
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (unlikely(data->backup_ghcb_active)) {
			/*
			 * Backup-GHCB is also already in use. There is no way
			 * to continue here so just kill the machine. To make
			 * panic() work, mark GHCBs inactive so that messages
			 * can be printed out.
			 */
			data->ghcb_active        = false;
			data->backup_ghcb_active = false;

			instrumentation_begin();
			panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use");
			instrumentation_end();
		}

		/* Mark backup_ghcb active before writing to it */
		data->backup_ghcb_active = true;

		state->ghcb = &data->backup_ghcb;

		/* Backup GHCB content */
		*state->ghcb = *ghcb;
	} else {
		state->ghcb = NULL;
		data->ghcb_active = true;
	}

	return ghcb;
}

noinstr void __sev_put_ghcb(struct ghcb_state *state)
{
	struct sev_es_runtime_data *data;
	struct ghcb *ghcb;

	WARN_ON(!irqs_disabled());

	if (!sev_cfg.ghcbs_initialized)
		return;

	data = this_cpu_read(runtime_data);
	ghcb = &data->ghcb_page;

	if (state->ghcb) {
		/* Restore GHCB from Backup */
		*ghcb = *state->ghcb;
		data->backup_ghcb_active = false;
		state->ghcb = NULL;
	} else {
		/*
		 * Invalidate the GHCB so a VMGEXIT instruction issued
		 * from userspace won't appear to be valid.
		 */
		vc_ghcb_invalidate(ghcb);
		data->ghcb_active = false;
	}
}

Annotation

Implementation Notes