linux-kernel - [PATCH v6 01/12] KVM: arm64: Don't depend on fallthrough to hide SYSTEM

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Message-Id: <20220504032446.4133305-2-oupton@google.com>
Date:   Wed,  4 May 2022 03:24:35 +0000
From:   Oliver Upton <oupton@...gle.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, maz@...nel.org, james.morse@....com,
        alexandru.elisei@....com, suzuki.poulose@....com,
        reijiw@...gle.com, ricarkol@...gle.com,
        Oliver Upton <oupton@...gle.com>
Subject: [PATCH v6 01/12] KVM: arm64: Don't depend on fallthrough to hide SYSTEM_RESET2

Depending on a fallthrough to the default case for hiding SYSTEM_RESET2
requires that any new case statements clean up the failure path for this
PSCI call.

Unhitch SYSTEM_RESET2 from the default case by setting val to
PSCI_RET_NOT_SUPPORTED outside of the switch statement. Apply the
cleanup to both the PSCI_1_1_FN_SYSTEM_RESET2 and
PSCI_1_0_FN_PSCI_FEATURES handlers.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@...gle.com>
Reviewed-by: Reiji Watanabe <reijiw@...gle.com>
---
 arch/arm64/kvm/psci.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index 708d80e8e60d..67fbd6ef022c 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -305,9 +305,9 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 
 static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 {
+	unsigned long val = PSCI_RET_NOT_SUPPORTED;
 	u32 psci_fn = smccc_get_function(vcpu);
 	u32 arg;
-	unsigned long val;
 	int ret = 1;
 
 	switch(psci_fn) {
@@ -320,6 +320,8 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 		if (val)
 			break;
 
+		val = PSCI_RET_NOT_SUPPORTED;
+
 		switch(arg) {
 		case PSCI_0_2_FN_PSCI_VERSION:
 		case PSCI_0_2_FN_CPU_SUSPEND:
@@ -338,13 +340,8 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 			break;
 		case PSCI_1_1_FN_SYSTEM_RESET2:
 		case PSCI_1_1_FN64_SYSTEM_RESET2:
-			if (minor >= 1) {
+			if (minor >= 1)
 				val = 0;
-				break;
-			}
-			fallthrough;
-		default:
-			val = PSCI_RET_NOT_SUPPORTED;
 			break;
 		}
 		break;
@@ -365,7 +362,7 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 			val = PSCI_RET_INVALID_PARAMS;
 			break;
 		}
-		fallthrough;
+		break;
 	default:
 		return kvm_psci_0_2_call(vcpu);
 	}
-- 
2.36.0.464.gb9c8b46e94-goog