KVM: arm64: Configure c15, PMU, and debug register traps on cpu load/put for VHE

We do not have to change the c15 trap setting on each switch to/from the
guest on VHE systems, because this setting only affects guest EL1/EL0
(and therefore not the VHE host).

The PMU and debug trap configuration can also be done on vcpu load/put
instead, because they don't affect how the VHE host kernel can access the
debug registers while executing KVM kernel code.

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

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 2b1fda9..949f2e7 100644 (file)
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -147,6 +147,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
 void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
 bool __fpsimd_enabled(void);
 
+void activate_traps_vhe_load(struct kvm_vcpu *vcpu);
+void deactivate_traps_vhe_put(void);
+
 u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
 void __noreturn __hyp_do_panic(unsigned long, ...);
 

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 5fbb77b..eab433f 100644 (file)
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -102,6 +102,8 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
 {
        u64 val;
 
+       __activate_traps_common(vcpu);
+
        val = CPTR_EL2_DEFAULT;
        val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ;
        write_sysreg(val, cptr_el2);
@@ -121,20 +123,12 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
                write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2);
 
        __activate_traps_fpsimd32(vcpu);
-       __activate_traps_common(vcpu);
        __activate_traps_arch()(vcpu);
 }
 
 static void __hyp_text __deactivate_traps_vhe(void)
 {
        extern char vectors[];  /* kernel exception vectors */
-       u64 mdcr_el2 = read_sysreg(mdcr_el2);
-
-       mdcr_el2 &= MDCR_EL2_HPMN_MASK |
-                   MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
-                   MDCR_EL2_TPMS;
-
-       write_sysreg(mdcr_el2, mdcr_el2);
        write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
        write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
        write_sysreg(vectors, vbar_el1);
@@ -144,6 +138,8 @@ static void __hyp_text __deactivate_traps_nvhe(void)
 {
        u64 mdcr_el2 = read_sysreg(mdcr_el2);
 
+       __deactivate_traps_common();
+
        mdcr_el2 &= MDCR_EL2_HPMN_MASK;
        mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
 
@@ -167,10 +163,27 @@ 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()();
 }
 
+void activate_traps_vhe_load(struct kvm_vcpu *vcpu)
+{
+       __activate_traps_common(vcpu);
+}
+
+void deactivate_traps_vhe_put(void)
+{
+       u64 mdcr_el2 = read_sysreg(mdcr_el2);
+
+       mdcr_el2 &= MDCR_EL2_HPMN_MASK |
+                   MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT |
+                   MDCR_EL2_TPMS;
+
+       write_sysreg(mdcr_el2, mdcr_el2);
+
+       __deactivate_traps_common();
+}
+
 static void __hyp_text __activate_vm(struct kvm *kvm)
 {
        write_sysreg(kvm->arch.vttbr, vttbr_el2);

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index aacba46..b3894df 100644 (file)
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -254,6 +254,8 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
        __sysreg_restore_el1_state(guest_ctxt);
 
        vcpu->arch.sysregs_loaded_on_cpu = true;
+
+       activate_traps_vhe_load(vcpu);
 }
 
 /**
@@ -275,6 +277,8 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
        if (!has_vhe())
                return;
 
+       deactivate_traps_vhe_put();
+
        __sysreg_save_el1_state(guest_ctxt);
        __sysreg_save_user_state(guest_ctxt);
        __sysreg32_save_state(vcpu);