From 8e3c54c8b6a9286b1571c4a4ba1d4afbd217f297 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Fri, 28 Sep 2018 14:39:20 +0100 Subject: [PATCH] KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST 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 in order to access the V-register content. For the variably-sized SVE registers, the appropriate set of slice IDs are enumerated, depending on the maximum vector length for the vcpu. As it currently stands, the SVE architecture never requires more than one slice to exist per register, so this patch adds no explicit support for enumerating multiple slices. The code can be extended straightforwardly to support this in the future, if needed. Signed-off-by: Dave Martin Reviewed-by: Julien Thierry Tested-by: zhang.lei Signed-off-by: Marc Zyngier --- arch/arm64/kvm/guest.c | 63 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 736d8cb8dad7..2aa80a59e2a2 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -222,6 +222,13 @@ out: #define KVM_SVE_ZREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_ZREG(0, 0)) #define KVM_SVE_PREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_PREG(0, 0)) +/* + * number of register slices required to cover each whole SVE register on vcpu + * NOTE: If you are tempted to modify this, you must also to rework + * sve_reg_to_region() to match: + */ +#define vcpu_sve_slices(vcpu) 1 + /* Bounds of a single SVE register slice within vcpu->arch.sve_state */ struct sve_state_reg_region { unsigned int koffset; /* offset into sve_state in kernel memory */ @@ -411,6 +418,56 @@ 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 = vcpu_sve_slices(vcpu); + + 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 *uindices) +{ + /* Only the first slice ever exists, for now */ + const unsigned int slices = vcpu_sve_slices(vcpu); + u64 reg; + unsigned int i, n; + int num_regs = 0; + + if (!vcpu_has_sve(vcpu)) + return 0; + + for (i = 0; i < slices; i++) { + for (n = 0; n < SVE_NUM_ZREGS; n++) { + reg = KVM_REG_ARM64_SVE_ZREG(n, i); + if (put_user(reg, uindices++)) + return -EFAULT; + + num_regs++; + } + + for (n = 0; n < SVE_NUM_PREGS; n++) { + reg = KVM_REG_ARM64_SVE_PREG(n, i); + if (put_user(reg, uindices++)) + return -EFAULT; + + num_regs++; + } + + reg = KVM_REG_ARM64_SVE_FFR(i); + if (put_user(reg, uindices++)) + return -EFAULT; + + num_regs++; + } + + return num_regs; +} + /** * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG * @@ -421,6 +478,7 @@ 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; @@ -442,6 +500,11 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices) return ret; uindices += ret; + ret = copy_sve_reg_indices(vcpu, uindices); + if (ret) + return ret; + uindices += ret; + ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices); if (ret) return ret; -- 2.30.2