linux-kernel - [tip: x86/urgent] x86/sev: Return an error on a returned non-zero SW

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Date:   Fri, 01 Oct 2021 09:52:34 -0000
From:   "tip-bot2 for Tom Lendacky" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Tom Lendacky <thomas.lendacky@....com>,
        Borislav Petkov <bp@...e.de>, <stable@...r.kernel.org>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/sev: Return an error on a returned non-zero
 SW_EXITINFO1[31:0]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     06f2ac3d4219bbbfd93d79e01966a42053084f11
Gitweb:        https://git.kernel.org/tip/06f2ac3d4219bbbfd93d79e01966a42053084f11
Author:        Tom Lendacky <thomas.lendacky@....com>
AuthorDate:    Thu, 30 Sep 2021 23:42:01 -05:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Fri, 01 Oct 2021 11:14:41 +02:00

x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0]

After returning from a VMGEXIT NAE event, SW_EXITINFO1[31:0] is checked
for a value of 1, which indicates an error and that SW_EXITINFO2
contains exception information. However, future versions of the GHCB
specification may define new values for SW_EXITINFO1[31:0], so really
any non-zero value should be treated as an error.

Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler")
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: <stable@...r.kernel.org> # 5.10+
Link: https://lkml.kernel.org/r/efc772af831e9e7f517f0439b13b41f56bad8784.1633063321.git.thomas.lendacky@amd.com
---
 arch/x86/kernel/sev-shared.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 9f90f46..bf1033a 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -130,6 +130,8 @@ static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
 		} else {
 			ret = ES_VMM_ERROR;
 		}
+	} else if (ghcb->save.sw_exit_info_1 & 0xffffffff) {
+		ret = ES_VMM_ERROR;
 	} else {
 		ret = ES_OK;
 	}