Hi Dave, On 19/03/2019 17:52, Dave Martin wrote: > In order to avoid the pointless complexity of maintaining two ioctl > register access views of the same data, this patch blocks ioctl > access to the FPSIMD V-registers on vcpus that support SVE. > > This will make it more straightforward to add SVE register access > support. > > Since SVE is an opt-in feature for userspace, this will not affect > existing users. > > Signed-off-by: Dave Martin <[email protected]> >
Reviewed-by: Julien Thierry <[email protected]> Cheer, Julien > --- > > (Julien Thierry's Reviewed-by dropped due to non-trivial refactoring) > > Changes since v5: > > * Refactored to cope with the removal of core_reg_size_from_offset() > (which was added by another series which will now be handled > independently). > > This leaves some duplication in that we still filter the V-regs out > in two places, but this no worse than other existing code in guest.c. > I plan to tidy this up independently later on. > --- > arch/arm64/kvm/guest.c | 48 ++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 36 insertions(+), 12 deletions(-) > > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c > index a391a61..756d0d6 100644 > --- a/arch/arm64/kvm/guest.c > +++ b/arch/arm64/kvm/guest.c > @@ -54,12 +54,19 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) > return 0; > } > > +static bool core_reg_offset_is_vreg(u64 off) > +{ > + return off >= KVM_REG_ARM_CORE_REG(fp_regs.vregs) && > + off < KVM_REG_ARM_CORE_REG(fp_regs.fpsr); > +} > + > static u64 core_reg_offset_from_id(u64 id) > { > return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE); > } > > -static int validate_core_offset(const struct kvm_one_reg *reg) > +static int validate_core_offset(const struct kvm_vcpu *vcpu, > + const struct kvm_one_reg *reg) > { > u64 off = core_reg_offset_from_id(reg->id); > int size; > @@ -91,11 +98,19 @@ static int validate_core_offset(const struct kvm_one_reg > *reg) > return -EINVAL; > } > > - if (KVM_REG_SIZE(reg->id) == size && > - IS_ALIGNED(off, size / sizeof(__u32))) > - return 0; > + if (KVM_REG_SIZE(reg->id) != size || > + !IS_ALIGNED(off, size / sizeof(__u32))) > + return -EINVAL; > > - return -EINVAL; > + /* > + * The KVM_REG_ARM64_SVE regs must be used instead of > + * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on > + * SVE-enabled vcpus: > + */ > + if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(off)) > + return -EINVAL; > + > + return 0; > } > > static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) > @@ -117,7 +132,7 @@ static int get_core_reg(struct kvm_vcpu *vcpu, const > struct kvm_one_reg *reg) > (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) > return -ENOENT; > > - if (validate_core_offset(reg)) > + if (validate_core_offset(vcpu, reg)) > return -EINVAL; > > if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id))) > @@ -142,7 +157,7 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const > struct kvm_one_reg *reg) > (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs) > return -ENOENT; > > - if (validate_core_offset(reg)) > + if (validate_core_offset(vcpu, reg)) > return -EINVAL; > > if (KVM_REG_SIZE(reg->id) > sizeof(tmp)) > @@ -195,13 +210,22 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, > struct kvm_regs *regs) > return -EINVAL; > } > > -static int kvm_arm_copy_core_reg_indices(u64 __user *uindices) > +static int copy_core_reg_indices(const struct kvm_vcpu *vcpu, > + u64 __user *uindices) > { > unsigned int i; > int n = 0; > const u64 core_reg = KVM_REG_ARM64 | KVM_REG_SIZE_U64 | > KVM_REG_ARM_CORE; > > for (i = 0; i < sizeof(struct kvm_regs) / sizeof(__u32); i++) { > + /* > + * The KVM_REG_ARM64_SVE regs must be used instead of > + * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on > + * SVE-enabled vcpus: > + */ > + if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(i)) > + continue; > + > if (uindices) { > if (put_user(core_reg | i, uindices)) > return -EFAULT; > @@ -214,9 +238,9 @@ static int kvm_arm_copy_core_reg_indices(u64 __user > *uindices) > return n; > } > > -static unsigned long num_core_regs(void) > +static unsigned long num_core_regs(const struct kvm_vcpu *vcpu) > { > - return kvm_arm_copy_core_reg_indices(NULL); > + return copy_core_reg_indices(vcpu, NULL); > } > > /** > @@ -281,7 +305,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu) > { > unsigned long res = 0; > > - res += num_core_regs(); > + res += num_core_regs(vcpu); > res += kvm_arm_num_sys_reg_descs(vcpu); > res += kvm_arm_get_fw_num_regs(vcpu); > res += NUM_TIMER_REGS; > @@ -298,7 +322,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 > __user *uindices) > { > int ret; > > - ret = kvm_arm_copy_core_reg_indices(uindices); > + ret = copy_core_reg_indices(vcpu, uindices); > if (ret) > return ret; > uindices += ret; > -- Julien Thierry _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
