On Fri, Jun 21, 2019 at 10:37:52AM +0100, Marc Zyngier wrote: > The VMPIDR_EL2 and VPIDR_EL2 are architecturally UNKNOWN at reset, but > let's be nice to a guest hypervisor behaving foolishly and reset these > to something reasonable anyway.
Why be nice? Generally we do try to initialise UNKNOWN regs to garbage, to help trip up badly-written guests. Cheers ---Dave > > Signed-off-by: Christoffer Dall <[email protected]> > Signed-off-by: Marc Zyngier <[email protected]> > --- > arch/arm64/kvm/sys_regs.c | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index e81be6debe07..693dd063c9c2 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -624,7 +624,7 @@ static void reset_amair_el1(struct kvm_vcpu *vcpu, const > struct sys_reg_desc *r) > vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1); > } > > -static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > +static u64 compute_reset_mpidr(struct kvm_vcpu *vcpu) > { > u64 mpidr; > > @@ -638,7 +638,24 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const > struct sys_reg_desc *r) > mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0); > mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1); > mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2); > - vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1); > + mpidr |= (1ULL << 31); > + > + return mpidr; > +} > + > +static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > +{ > + vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), MPIDR_EL1); > +} > + > +static void reset_vmpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > +{ > + vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), VMPIDR_EL2); > +} > + > +static void reset_vpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > +{ > + vcpu_write_sys_reg(vcpu, read_cpuid_id(), VPIDR_EL2); > } > > static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) > @@ -1668,8 +1685,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { > */ > { SYS_DESC(SYS_PMCCFILTR_EL0), access_pmu_evtyper, reset_val, > PMCCFILTR_EL0, 0 }, > > - { SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_val, VPIDR_EL2, 0 }, > - { SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_val, VMPIDR_EL2, 0 }, > + { SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_vpidr, VPIDR_EL2 }, > + { SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_vmpidr, VMPIDR_EL2 }, > > { SYS_DESC(SYS_SCTLR_EL2), access_rw, reset_val, SCTLR_EL2, 0 }, > { SYS_DESC(SYS_ACTLR_EL2), access_rw, reset_val, ACTLR_EL2, 0 }, > -- > 2.20.1 > > > _______________________________________________ > linux-arm-kernel mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
