[PATCH v5 31/40] KVM: arm64: Move common VHE/non-VHE trap config in separate functions

[Christoffer Dall]

From: Christoffer Dall <christoffer.dall at linaro.org>

As we are about to be more lazy with some of the trap configuration
register read/writes for VHE systems, move the logic that is currently
shared between VHE and non-VHE into a separate function which can be
called from either the world-switch path or from vcpu_load/vcpu_put.

Reviewed-by: Marc Zyngier <marc.zyngier at arm.com>
Reviewed-by: Andrew Jones <drjones at redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
---

Notes:
    Changes since v4:
     - Added blank newline to separate logic blocks in
       __activate_traps_common.
    
    Changes since v3:
     - Separate fpsimd32 trap configuration into a separate function
       which is still called from __activate_traps, because we no longer
       defer saving/restoring of VFP registers to load/put.

 arch/arm64/kvm/hyp/switch.c | 77 +++++++++++++++++++++++++++------------------
 1 file changed, 46 insertions(+), 31 deletions(-)

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 9b0380d3c9c3..9d90bda3c2cc 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -56,7 +56,46 @@ static void __hyp_text __fpsimd_save_fpexc32(struct kvm_vcpu *vcpu)
 	vcpu->arch.ctxt.sys_regs[FPEXC32_EL2] = read_sysreg(fpexc32_el2);
 }
 
-static void __hyp_text __activate_traps_vhe(void)
+static void __hyp_text __activate_traps_fpsimd32(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * We are about to set CPTR_EL2.TFP to trap all floating point
+	 * register accesses to EL2, however, the ARM ARM clearly states that
+	 * traps are only taken to EL2 if the operation would not otherwise
+	 * trap to EL1.  Therefore, always make sure that for 32-bit guests,
+	 * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
+	 * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
+	 * it will cause an exception.
+	 */
+	if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
+		write_sysreg(1 << 30, fpexc32_el2);
+		isb();
+	}
+}
+
+static void __hyp_text __activate_traps_common(struct kvm_vcpu *vcpu)
+{
+	/* Trap on AArch32 cp15 c15 (impdef sysregs) accesses (EL1 or EL0) */
+	write_sysreg(1 << 15, hstr_el2);
+
+	/*
+	 * Make sure we trap PMU access from EL0 to EL2. Also sanitize
+	 * PMSELR_EL0 to make sure it never contains the cycle
+	 * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
+	 * EL1 instead of being trapped to EL2.
+	 */
+	write_sysreg(0, pmselr_el0);
+	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
+	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
+}
+
+static void __hyp_text __deactivate_traps_common(void)
+{
+	write_sysreg(0, hstr_el2);
+	write_sysreg(0, pmuserenr_el0);
+}
+
+static void __hyp_text __activate_traps_vhe(struct kvm_vcpu *vcpu)
 {
 	u64 val;
 
@@ -68,7 +107,7 @@ static void __hyp_text __activate_traps_vhe(void)
 	write_sysreg(kvm_get_hyp_vector(), vbar_el1);
 }
 
-static void __hyp_text __activate_traps_nvhe(void)
+static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
 {
 	u64 val;
 
@@ -85,37 +124,14 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
 {
 	u64 hcr = vcpu->arch.hcr_el2;
 
-	/*
-	 * We are about to set CPTR_EL2.TFP to trap all floating point
-	 * register accesses to EL2, however, the ARM ARM clearly states that
-	 * traps are only taken to EL2 if the operation would not otherwise
-	 * trap to EL1.  Therefore, always make sure that for 32-bit guests,
-	 * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
-	 * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to
-	 * it will cause an exception.
-	 */
-	if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd()) {
-		write_sysreg(1 << 30, fpexc32_el2);
-		isb();
-	}
+	write_sysreg(hcr, hcr_el2);
 
 	if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE))
 		write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
 
-	write_sysreg(hcr, hcr_el2);
-
-	/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
-	write_sysreg(1 << 15, hstr_el2);
-	/*
-	 * Make sure we trap PMU access from EL0 to EL2. Also sanitize
-	 * PMSELR_EL0 to make sure it never contains the cycle
-	 * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
-	 * EL1 instead of being trapped to EL2.
-	 */
-	write_sysreg(0, pmselr_el0);
-	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
-	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
-	__activate_traps_arch()();
+	__activate_traps_fpsimd32(vcpu);
+	__activate_traps_common(vcpu);
+	__activate_traps_arch()(vcpu);
 }
 
 static void __hyp_text __deactivate_traps_vhe(void)
@@ -160,9 +176,8 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.hcr_el2 & HCR_VSE)
 		vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);
 
+	__deactivate_traps_common();
 	__deactivate_traps_arch()();
-	write_sysreg(0, hstr_el2);
-	write_sysreg(0, pmuserenr_el0);
 }
 
 static void __hyp_text __activate_vm(struct kvm *kvm)
-- 
2.14.2