linux-kernel - [PATCH 51/62] x86/sev-es: Handle #AC Events

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Message-Id: <20200211135256.24617-52-joro@8bytes.org>
Date:   Tue, 11 Feb 2020 14:52:45 +0100
From:   Joerg Roedel <joro@...tes.org>
To:     x86@...nel.org
Cc:     hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Hellstrom <thellstrom@...are.com>,
        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>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 51/62] x86/sev-es: Handle #AC Events

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

Implement a handler for #VC exceptions caused by #AC exceptions. The #AC
exception is just forwarded to do_alignment_check() and not pushed down
to the hypervisor, as requested by the SEV-ES GHCB Standardization
Specification.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/kernel/sev-es.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 6bd2cae7eb9c..1b873d00e38f 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -375,6 +375,10 @@ static enum es_result handle_vc_exception(struct es_em_ctxt *ctxt,
 	case SVM_EXIT_WRITE_DR7:
 		result = handle_dr7_write(ghcb, ctxt, early);
 		break;
+	case SVM_EXIT_EXCP_BASE + X86_TRAP_AC:
+		do_alignment_check(ctxt->regs, 0);
+		result = ES_RETRY;
+		break;
 	case SVM_EXIT_RDTSC:
 	case SVM_EXIT_RDTSCP:
 		result = handle_rdtsc(ghcb, ctxt, exit_code);
-- 
2.17.1