Commit 6c0f74d6 authored by Brijesh Singh's avatar Brijesh Singh Committed by Borislav Petkov
Browse files

x86/sev: Define the Linux-specific guest termination reasons 



The GHCB specification defines the reason code for reason set 0. The
reason codes defined in the set 0 do not cover all possible causes for a
guest to request termination.

The reason sets 1 to 255 are reserved for the vendor-specific codes.
Reserve the reason set 1 for the Linux guest. Define the error codes for
reason set 1 so that one can have meaningful termination reasons and thus
better guest failure diagnosis.

While at it, change sev_es_terminate() to accept a reason set parameter.

  [ bp: Massage commit message. ]

Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarVenu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-11-brijesh.singh@amd.com
parent f742b90e

arch/x86/boot/compressed/sev.c

+3 −3
Original line number Diff line number Diff line
@@ -119,7 +119,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, 
static bool early_setup_sev_es(void)

{

	if (!sev_es_negotiate_protocol())

		sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);

		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);



	if (set_page_decrypted((unsigned long)&boot_ghcb_page))

		return false;
@@ -172,7 +172,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code) 
	enum es_result result;



	if (!boot_ghcb && !early_setup_sev_es())

		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);

		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);



	vc_ghcb_invalidate(boot_ghcb);

	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -199,7 +199,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code) 
	if (result == ES_OK)

		vc_finish_insn(&ctxt);

	else if (result != ES_RETRY)

		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);

		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);

}



void sev_enable(struct boot_params *bp)

arch/x86/include/asm/sev-common.h

+8 −0
Original line number Diff line number Diff line
@@ -73,9 +73,17 @@ 
	 /* GHCBData[23:16] */				\

	((((u64)reason_val) & 0xff) << 16))



/* Error codes from reason set 0 */

#define SEV_TERM_SET_GEN		0

#define GHCB_SEV_ES_GEN_REQ		0

#define GHCB_SEV_ES_PROT_UNSUPPORTED	1



/* Linux-specific reason codes (used with reason set 1) */

#define SEV_TERM_SET_LINUX		1

#define GHCB_TERM_REGISTER		0	/* GHCB GPA registration failure */

#define GHCB_TERM_PSC			1	/* Page State Change failure */

#define GHCB_TERM_PVALIDATE		2	/* Pvalidate failure */



#define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)



/*

arch/x86/kernel/sev-shared.c

+4 −7
Original line number Diff line number Diff line
@@ -24,15 +24,12 @@ static bool __init sev_es_check_cpu_features(void) 
	return true;

}



static void __noreturn sev_es_terminate(unsigned int reason)

static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason)

{

	u64 val = GHCB_MSR_TERM_REQ;



	/*

	 * Tell the hypervisor what went wrong - only reason-set 0 is

	 * currently supported.

	 */

	val |= GHCB_SEV_TERM_REASON(0, reason);

	/* Tell the hypervisor what went wrong. */

	val |= GHCB_SEV_TERM_REASON(set, reason);



	/* Request Guest Termination from Hypvervisor */

	sev_es_wr_ghcb_msr(val);
@@ -221,7 +218,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code) 


fail:

	/* Terminate the guest */

	sev_es_terminate(GHCB_SEV_ES_GEN_REQ);

	sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);

}



static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,

arch/x86/kernel/sev.c

+2 −2
Original line number Diff line number Diff line
@@ -1337,7 +1337,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication) 
		show_regs(regs);



		/* Ask hypervisor to sev_es_terminate */

		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);

		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);



		/* If that fails and we get here - just panic */

		panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1385,7 +1385,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs) 


	/* Do initial setup or terminate the guest */

	if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))

		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);

		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);



	vc_ghcb_invalidate(boot_ghcb);