On Fri, Feb 23, 2018 at 02:30:54PM +0000, Julien Grall wrote:
> Hi Christoffer,
> 
> On 15/02/18 21:03, Christoffer Dall wrote:
> >@@ -85,37 +123,14 @@ 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);
> 
> OOI, any reason to move the write to HCR_EL2 just before the if?
> 

I suppose not, I think this is just a rebasing artifact.

> >-
> >-    /* 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 +175,8 @@ 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)
> >
> 
Thanks,
-Christoffer
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