Subject: [PATCH 18/26] KVM: arm64: Don't use empty structures as CPU reset state

From: Marc Zyngier <[email-masked]>
Date: Wed, 22 Apr 2020 13:00:42 +0100

Keeping empty structure as the vcpu state initializer is slightly
wasteful: we only want to set pstate, and zero everything else.
Just do that.

Signed-off-by: Marc Zyngier <[email-masked]>
---
 arch/arm64/kvm/reset.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 241db35a7ef4f..895d7d9ad1866 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -37,15 +37,11 @@ static u32 kvm_ipa_limit;
 /*
  * ARMv8 Reset Values
  */
-static const struct kvm_regs default_regs_reset = {
-	.regs.pstate = (PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT |
-			PSR_F_BIT | PSR_D_BIT),
-};
+#define VCPU_RESET_PSTATE_EL1	(PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
+				 PSR_F_BIT | PSR_D_BIT)
 
-static const struct kvm_regs default_regs_reset32 = {
-	.regs.pstate = (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT |
-			PSR_AA32_I_BIT | PSR_AA32_F_BIT),
-};
+#define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
+				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
 
 static bool cpu_has_32bit_el1(void)
 {
@@ -261,6 +257,7 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	const struct kvm_regs *cpu_reset;
 	int ret = -EINVAL;
 	bool loaded;
+	u32 pstate;
 
 	/* Reset PMU outside of the non-preemptible section */
 	kvm_pmu_vcpu_reset(vcpu);
@@ -291,16 +288,17 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
 			if (!cpu_has_32bit_el1())
 				goto out;
-			cpu_reset = &default_regs_reset32;
+			pstate = VCPU_RESET_PSTATE_SVC;
 		} else {
-			cpu_reset = &default_regs_reset;
+			pstate = VCPU_RESET_PSTATE_EL1;
 		}
 
 		break;
 	}
 
 	/* Reset core registers */
-	memcpy(vcpu_gp_regs(vcpu), cpu_reset, sizeof(*cpu_reset));
+	memset(vcpu_gp_regs(vcpu), 0, sizeof(*cpu_reset));
+	vcpu_gp_regs(vcpu)->regs.pstate = pstate;
 
 	/* Reset system registers */
 	kvm_reset_sys_regs(vcpu);
-- 
2.26.1

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