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

Marc Zyngier
2020-04-22T12:21:23Z

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 <maz@kernel.org>
---
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