linux-kernel - [PATCH v2 7/7] x86/sev-es: Replace open-coded hlt-loops with sev_es

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Date:   Wed, 10 Mar 2021 09:43:25 +0100
From:   Joerg Roedel <joro@...tes.org>
To:     x86@...nel.org
Cc:     Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
        hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        David Rientjes <rientjes@...gle.com>,
        Cfir Cohen <cfir@...gle.com>,
        Erdem Aktas <erdemaktas@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mike Stunes <mstunes@...are.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Martin Radev <martin.b.radev@...il.com>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH v2 7/7] x86/sev-es: Replace open-coded hlt-loops with sev_es_terminate()

From: Joerg Roedel <jroedel@...e.de>

There are a few places left in the SEV-ES C code where hlt loops and/or
terminate requests are implemented. Replace them all with calls to
sev_es_terminate().

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/boot/compressed/sev-es.c | 12 +++---------
 arch/x86/kernel/sev-es-shared.c   | 10 +++-------
 2 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/arch/x86/boot/compressed/sev-es.c b/arch/x86/boot/compressed/sev-es.c
index 27826c265aab..d904bd56b3e3 100644
--- a/arch/x86/boot/compressed/sev-es.c
+++ b/arch/x86/boot/compressed/sev-es.c
@@ -200,14 +200,8 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	}
 
 finish:
-	if (result == ES_OK) {
+	if (result == ES_OK)
 		vc_finish_insn(&ctxt);
-	} else if (result != ES_RETRY) {
-		/*
-		 * For now, just halt the machine. That makes debugging easier,
-		 * later we just call sev_es_terminate() here.
-		 */
-		while (true)
-			asm volatile("hlt\n");
-	}
+	else if (result != ES_RETRY)
+		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 }
diff --git a/arch/x86/kernel/sev-es-shared.c b/arch/x86/kernel/sev-es-shared.c
index cdc04d091242..7c34be61258e 100644
--- a/arch/x86/kernel/sev-es-shared.c
+++ b/arch/x86/kernel/sev-es-shared.c
@@ -24,7 +24,7 @@ static bool __init sev_es_check_cpu_features(void)
 	return true;
 }
 
-static void sev_es_terminate(unsigned int reason)
+static void __noreturn sev_es_terminate(unsigned int reason)
 {
 	u64 val = GHCB_SEV_TERMINATE;
 
@@ -210,12 +210,8 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 	return;
 
 fail:
-	sev_es_wr_ghcb_msr(GHCB_SEV_TERMINATE);
-	VMGEXIT();
-
-	/* Shouldn't get here - if we do halt the machine */
-	while (true)
-		asm volatile("hlt\n");
+	/* Terminate the guest */
+	sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,
-- 
2.30.1