linux-kernel - [PATCH v2 5/6] KVM: SEV: use mutex guard in snp_handle_guest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260120201013.3931334-8-clopez@suse.de>
Date: Tue, 20 Jan 2026 21:10:13 +0100
From: Carlos López <clopez@...e.de>
To: kvm@...r.kernel.org,
	seanjc@...gle.com,
	pbonzini@...hat.com
Cc: pankaj.gupta@....com,
	tglx@...utronix.de,
	mingo@...hat.com,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	linux-kernel@...r.kernel.org,
	Carlos López <clopez@...e.de>,
	Borislav Petkov <bp@...en8.de>
Subject: [PATCH v2 5/6] KVM: SEV: use mutex guard in snp_handle_guest_req()

Simplify the error paths in snp_handle_guest_req() by using a mutex
guard, allowing early return instead of using gotos.

Signed-off-by: Carlos López <clopez@...e.de>
---
 arch/x86/kvm/svm/sev.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 37ff48a876a5..d3fa0963465d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4089,12 +4089,10 @@ static int snp_handle_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_
 	if (!sev_snp_guest(kvm))
 		return -EINVAL;
 
-	mutex_lock(&sev->guest_req_mutex);
+	guard(mutex)(&sev->guest_req_mutex);
 
-	if (kvm_read_guest(kvm, req_gpa, sev->guest_req_buf, PAGE_SIZE)) {
-		ret = -EIO;
-		goto out_unlock;
-	}
+	if (kvm_read_guest(kvm, req_gpa, sev->guest_req_buf, PAGE_SIZE))
+		return -EIO;
 
 	data.gctx_paddr = __psp_pa(sev->snp_context);
 	data.req_paddr = __psp_pa(sev->guest_req_buf);
@@ -4107,21 +4105,16 @@ static int snp_handle_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_
 	 */
 	ret = sev_issue_cmd(kvm, SEV_CMD_SNP_GUEST_REQUEST, &data, &fw_err);
 	if (ret && !fw_err)
-		goto out_unlock;
+		return ret;
 
-	if (kvm_write_guest(kvm, resp_gpa, sev->guest_resp_buf, PAGE_SIZE)) {
-		ret = -EIO;
-		goto out_unlock;
-	}
+	if (kvm_write_guest(kvm, resp_gpa, sev->guest_resp_buf, PAGE_SIZE))
+		return -EIO;
 
 	/* No action is requested *from KVM* if there was a firmware error. */
 	svm_vmgexit_no_action(svm, SNP_GUEST_ERR(0, fw_err));
 
-	ret = 1; /* resume guest */
-
-out_unlock:
-	mutex_unlock(&sev->guest_req_mutex);
-	return ret;
+	/* resume guest */
+	return 1;
 }
 
 static int snp_handle_ext_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa)
-- 
2.51.0