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From: Borislav Petkov <bp@alien8.de>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Joerg Roedel <jroedel@suse.de>,
	Brijesh Singh <brijesh.singh@amd.com>,
	stable@vger.kernel.org
Subject: [PATCH] x86/sev: Carve out HV call's return value verification
Date: Mon, 11 Oct 2021 19:13:40 +0200	[thread overview]
Message-ID: <YWRwxImd9Qcls/Yy@zn.tnic> (raw)
In-Reply-To: <YVcTDM9hshdlUqbN@zn.tnic>

Now as a proper patch with typo fixed and tested:

---
From: Borislav Petkov <bp@suse.de>

Carve out the verification of the HV call return value into a separate
helper and make it more readable.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/sev-shared.c | 53 ++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index bf1033a62e48..4579c38a11c4 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -94,25 +94,15 @@ static void vc_finish_insn(struct es_em_ctxt *ctxt)
 	ctxt->regs->ip += ctxt->insn.length;
 }
 
-static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
-					  struct es_em_ctxt *ctxt,
-					  u64 exit_code, u64 exit_info_1,
-					  u64 exit_info_2)
+static enum es_result verify_exception_info(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
 {
-	enum es_result ret;
+	u32 ret;
 
-	/* Fill in protocol and format specifiers */
-	ghcb->protocol_version = GHCB_PROTOCOL_MAX;
-	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
+	ret = ghcb->save.sw_exit_info_1 & GENMASK_ULL(31, 0);
+	if (!ret)
+		return ES_OK;
 
-	ghcb_set_sw_exit_code(ghcb, exit_code);
-	ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
-	ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
-
-	sev_es_wr_ghcb_msr(__pa(ghcb));
-	VMGEXIT();
-
-	if ((ghcb->save.sw_exit_info_1 & 0xffffffff) == 1) {
+	if (ret == 1) {
 		u64 info = ghcb->save.sw_exit_info_2;
 		unsigned long v;
 
@@ -124,19 +114,34 @@ static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
 		    ((v == X86_TRAP_GP) || (v == X86_TRAP_UD)) &&
 		    ((info & SVM_EVTINJ_TYPE_MASK) == SVM_EVTINJ_TYPE_EXEPT)) {
 			ctxt->fi.vector = v;
+
 			if (info & SVM_EVTINJ_VALID_ERR)
 				ctxt->fi.error_code = info >> 32;
-			ret = ES_EXCEPTION;
-		} else {
-			ret = ES_VMM_ERROR;
+
+			return ES_EXCEPTION;
 		}
-	} else if (ghcb->save.sw_exit_info_1 & 0xffffffff) {
-		ret = ES_VMM_ERROR;
-	} else {
-		ret = ES_OK;
 	}
 
-	return ret;
+	return ES_VMM_ERROR;
+}
+
+static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
+					  struct es_em_ctxt *ctxt,
+					  u64 exit_code, u64 exit_info_1,
+					  u64 exit_info_2)
+{
+	/* Fill in protocol and format specifiers */
+	ghcb->protocol_version = GHCB_PROTOCOL_MAX;
+	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
+
+	ghcb_set_sw_exit_code(ghcb, exit_code);
+	ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
+	ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
+
+	sev_es_wr_ghcb_msr(__pa(ghcb));
+	VMGEXIT();
+
+	return verify_exception_info(ghcb, ctxt);
 }
 
 /*
-- 
2.29.2


-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

      reply	other threads:[~2021-10-11 17:13 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01  4:42 [PATCH] x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0] Tom Lendacky
2021-10-01  9:43 ` Borislav Petkov
2021-10-01 13:45   ` Tom Lendacky
2021-10-01 13:54     ` Borislav Petkov
2021-10-11 17:13       ` Borislav Petkov [this message]

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