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]> --- Changes since RFC v2: * New patch The initial code was split from "KVM: arm64/sve: Add SVE support to register access ioctl interface". However, some additional refactoring makes this change quite noisy: for ease of review, I decided it was best to keep the two parts of the change separate. * Move core_reg_offset_is_vreg() before validate_core_reg_id() (which now makes use of it). * Move rejection of KVM_REG_ARM_CORE view of the FPSIMD V-regs on SVE-enabled vcpus into validate_core_reg_id(), so that it can be applied everywhere appropriate instead of being open-coded. This requires vcpu to be pushed down into a few code paths (This is the noise alluded to above). --- arch/arm64/kvm/guest.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 0bf0ed3..e1ea73e 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -83,7 +83,13 @@ static int core_reg_size_from_offset(u64 off) return -EINVAL; } -static int validate_core_reg_id(u64 id) +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 int validate_core_reg_id(const struct kvm_vcpu *vcpu, u64 id) { u64 off = core_reg_offset_from_id(id); int size = core_reg_size_from_offset(off); @@ -91,10 +97,18 @@ static int validate_core_reg_id(u64 id) if (size < 0) return size; - if (KVM_REG_SIZE(id) == size && IS_ALIGNED(off, size / sizeof(__u32))) - return 0; + if (KVM_REG_SIZE(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) @@ -116,7 +130,7 @@ 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_reg_id(reg->id)) + if (validate_core_reg_id(vcpu, reg->id)) return -EINVAL; if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id))) @@ -141,7 +155,7 @@ 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_reg_id(reg->id)) + if (validate_core_reg_id(vcpu, reg->id)) return -EINVAL; if (KVM_REG_SIZE(reg->id) > sizeof(tmp)) @@ -194,7 +208,8 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs) return -EINVAL; } -static int copy_core_reg_indices(u64 __user **uind) +static int copy_core_reg_indices(const struct kvm_vcpu *vcpu, + u64 __user **uind) { unsigned int i; int total = 0; @@ -228,7 +243,7 @@ static int copy_core_reg_indices(u64 __user **uind) break; } - if (validate_core_reg_id(id)) + if (validate_core_reg_id(vcpu, id)) continue; if (uind) { @@ -243,9 +258,9 @@ static int copy_core_reg_indices(u64 __user **uind) return total; } -static unsigned long num_core_regs(void) +static unsigned long num_core_regs(const struct kvm_vcpu *vcpu) { - return copy_core_reg_indices(NULL); + return copy_core_reg_indices(vcpu, NULL); } /** @@ -310,7 +325,7 @@ 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; @@ -327,7 +342,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) { int ret; - ret = copy_core_reg_indices(&uindices); + ret = copy_core_reg_indices(vcpu, &uindices); if (ret < 0) return ret; -- 2.1.4 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
