From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [PATCH v4 16/25] KVM: arm64: Reject ioctl access to FPSIMD V-regs on SVE vcpus Date: Thu, 17 Jan 2019 20:33:30 +0000 Message-ID: <1547757219-19439-17-git-send-email-Dave.Martin@arm.com> References: <1547757219-19439-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 75C104A382 for ; Thu, 17 Jan 2019 15:35:05 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cUC3KlOcQBJC for ; Thu, 17 Jan 2019 15:35:04 -0500 (EST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 655A94A3C8 for ; Thu, 17 Jan 2019 15:35:03 -0500 (EST) In-Reply-To: <1547757219-19439-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: kvmarm@lists.cs.columbia.edu Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu 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 --- arch/arm64/kvm/guest.c | 38 +++++++++++++++++++++++++++----------- 1 file changed, 27 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 65f4338..ffa38d4 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -94,7 +94,14 @@ static int core_reg_size_from_offset(u64 off) return -EINVAL; } -static int validate_core_offset(const struct kvm_one_reg *reg) +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_offset(const struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) { u64 off = core_reg_offset_from_id(reg->id); int size = core_reg_size_from_offset(off); @@ -102,10 +109,18 @@ static int validate_core_offset(const struct kvm_one_reg *reg) if (size < 0) return -EINVAL; - if (KVM_REG_SIZE(reg->id) == size) - return 0; + if (KVM_REG_SIZE(reg->id) != size) + 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) @@ -127,7 +142,7 @@ 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))) @@ -152,7 +167,7 @@ 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)) @@ -205,7 +220,8 @@ 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 n = 0; @@ -247,9 +263,9 @@ static int copy_core_reg_indices(u64 __user **uind) return n; } -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); } /** @@ -314,7 +330,7 @@ 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; @@ -331,7 +347,7 @@ 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