Re: [PATCH v5 19/26] KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST
From: Julien Thierry <hidden>
Date: 2019-02-21 16:28:31
Also in:
kvmarm
On 18/02/2019 19:52, Dave Martin wrote:
This patch includes the SVE register IDs in the list returned by KVM_GET_REG_LIST, as appropriate. On a non-SVE-enabled vcpu, no new IDs are added. On an SVE-enabled vcpu, IDs for the FPSIMD V-registers are removed from the list, since userspace is required to access the Z- registers instead to access their context. For the variably-sized SVE registers, the appropriate set of slice IDs are enumerated, depending on the maximum vector length for the vcpu. Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Julien Thierry <redacted>
quoted hunk ↗ jump to hunk
--- Changes since v4: * Drop KVM_SVE_SLICES(), which is no longer used due to the dropping of register multi-slice support from the series. * Drop register multi-slice support. --- arch/arm64/kvm/guest.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+)diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 8cfa889..4a2ad60 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c@@ -366,6 +366,14 @@ static int copy_core_reg_indices(const struct kvm_vcpu *vcpu, continue; } + /* + * 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 (uind) { if (put_user(reg, *uind)) return -EFAULT;@@ -436,6 +444,44 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0; } +static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu) +{ + /* Only the first slice ever exists, for now */ + const unsigned int slices = 1; + + if (!vcpu_has_sve(vcpu)) + return 0; + + return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */); +} + +static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu, u64 __user **uind) +{ + /* Only the first slice ever exists, for now */ + const unsigned int slices = 1; + unsigned int i, n; + + if (!vcpu_has_sve(vcpu)) + return 0; + + for (i = 0; i < slices; i++) { + for (n = 0; n < SVE_NUM_ZREGS; n++) { + if (put_user(KVM_REG_ARM64_SVE_ZREG(n, i), (*uind)++)) + return -EFAULT; + } + + for (n = 0; n < SVE_NUM_PREGS; n++) { + if (put_user(KVM_REG_ARM64_SVE_PREG(n, i), (*uind)++)) + return -EFAULT; + } + + if (put_user(KVM_REG_ARM64_SVE_FFR(i), (*uind)++)) + return -EFAULT; + } + + return 0; +} + /** * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG *@@ -446,6 +492,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu) unsigned long res = 0; res += num_core_regs(vcpu); + res += num_sve_regs(vcpu); res += kvm_arm_num_sys_reg_descs(vcpu); res += kvm_arm_get_fw_num_regs(vcpu); res += NUM_TIMER_REGS;@@ -466,6 +513,10 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) if (ret < 0) return ret; + ret = copy_sve_reg_indices(vcpu, &uindices); + if (ret) + return ret; + ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices); if (ret) return ret;
-- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel