linux-kernel - [PATCH Part1 RFC v2 07/20] x86/sev: Define error codes for reason set 1.

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Message-Id: <20210430121616.2295-8-brijesh.singh@amd.com>
Date:   Fri, 30 Apr 2021 07:16:03 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     tglx@...utronix.de, bp@...en8.de, jroedel@...e.de,
        thomas.lendacky@....com, pbonzini@...hat.com, mingo@...hat.com,
        dave.hansen@...el.com, rientjes@...gle.com, seanjc@...gle.com,
        peterz@...radead.org, hpa@...or.com, tony.luck@...el.com,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH Part1 RFC v2 07/20] x86/sev: Define error codes for reason set 1.

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 set 1 to 255 is reserved for the vendor-specific codes.
Use the reason set 1 for the Linux guest. Define an error codes for
reason set 1.

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

Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
 arch/x86/boot/compressed/sev.c    | 6 +++---
 arch/x86/include/asm/sev-common.h | 5 +++++
 arch/x86/kernel/sev-shared.c      | 6 +++---
 arch/x86/kernel/sev.c             | 4 ++--
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 670e998fe930..6d9055427f37 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -122,7 +122,7 @@ 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_REASON_PROTOCOL_UNSUPPORTED);
+		sev_es_terminate(0, GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED);
 
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
@@ -175,7 +175,7 @@ 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_REASON_GENERAL_REQUEST);
+		sev_es_terminate(0, GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 
 	vc_ghcb_invalidate(boot_ghcb);
 	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,5 +202,5 @@ 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_REASON_GENERAL_REQUEST);
+		sev_es_terminate(0, GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 }
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 07b8612bf182..733fca403ae5 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -128,4 +128,9 @@ struct __packed snp_page_state_change {
 
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 
+/* Linux specific reason codes (used with reason set 1) */
+#define GHCB_TERM_REGISTER		0	/* GHCB GPA registration failure */
+#define GHCB_TERM_PSC			1	/* Page State Change faiilure */
+#define GHCB_TERM_PVALIDATE		2	/* Pvalidate failure */
+
 #endif
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 874f911837db..3f9b06a04395 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -32,7 +32,7 @@ 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;
 
@@ -40,7 +40,7 @@ static void __noreturn sev_es_terminate(unsigned int reason)
 	 * Tell the hypervisor what went wrong - only reason-set 0 is
 	 * currently supported.
 	 */
-	val |= GHCB_SEV_TERM_REASON(0, reason);
+	val |= GHCB_SEV_TERM_REASON(set, reason);
 
 	/* Request Guest Termination from Hypvervisor */
 	sev_es_wr_ghcb_msr(val);
@@ -240,7 +240,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 
 fail:
 	/* Terminate the guest */
-	sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+	sev_es_terminate(0, GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 9578c82832aa..97be0fe666ab 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1383,7 +1383,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
 		show_regs(regs);
 
 		/* Ask hypervisor to sev_es_terminate */
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(0, GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 
 		/* If that fails and we get here - just panic */
 		panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1416,7 +1416,7 @@ 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_REASON_GENERAL_REQUEST);
+		sev_es_terminate(0, GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 
 	vc_ghcb_invalidate(boot_ghcb);
 
-- 
2.17.1