From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Thierry Subject: Re: [PATCH v5 17/26] KVM: arm64: Reject ioctl access to FPSIMD V-regs on SVE vcpus Date: Thu, 21 Feb 2019 12:06:23 +0000 Message-ID: <696ae744-c016-9cc2-d393-fd321d341df4@arm.com> References: <1550519559-15915-1-git-send-email-Dave.Martin@arm.com> <1550519559-15915-18-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 D7B6E4A331 for ; Thu, 21 Feb 2019 07:06:32 -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 SFFbTCd0ZWYe for ; Thu, 21 Feb 2019 07:06:31 -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 2F6894A2BE for ; Thu, 21 Feb 2019 07:06:31 -0500 (EST) In-Reply-To: <1550519559-15915-18-git-send-email-Dave.Martin@arm.com> Content-Language: en-US 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: Dave Martin , kvmarm@lists.cs.columbia.edu Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On 18/02/2019 19:52, 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 Reviewed-by: Julien Thierry > --- > 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 f83fe22..f491456 100644 > --- a/arch/arm64/kvm/guest.c > +++ b/arch/arm64/kvm/guest.c > @@ -95,7 +95,14 @@ 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); > @@ -103,10 +110,18 @@ 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) > @@ -128,7 +143,7 @@ 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))) > @@ -153,7 +168,7 @@ 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)) > @@ -206,7 +221,8 @@ 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; > @@ -248,9 +264,9 @@ 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); > } > > /** > @@ -315,7 +331,7 @@ 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; > @@ -332,7 +348,7 @@ 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; > > -- Julien Thierry From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5EC0C43381 for ; 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Thu, 21 Feb 2019 04:06:26 -0800 (PST) Subject: Re: [PATCH v5 17/26] KVM: arm64: Reject ioctl access to FPSIMD V-regs on SVE vcpus To: Dave Martin , kvmarm@lists.cs.columbia.edu References: <1550519559-15915-1-git-send-email-Dave.Martin@arm.com> <1550519559-15915-18-git-send-email-Dave.Martin@arm.com> From: Julien Thierry Message-ID: <696ae744-c016-9cc2-d393-fd321d341df4@arm.com> Date: Thu, 21 Feb 2019 12:06:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1550519559-15915-18-git-send-email-Dave.Martin@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190221_040633_001394_AF85FEF7 X-CRM114-Status: GOOD ( 22.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 18/02/2019 19:52, 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 Reviewed-by: Julien Thierry > --- > 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 f83fe22..f491456 100644 > --- a/arch/arm64/kvm/guest.c > +++ b/arch/arm64/kvm/guest.c > @@ -95,7 +95,14 @@ 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); > @@ -103,10 +110,18 @@ 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) > @@ -128,7 +143,7 @@ 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))) > @@ -153,7 +168,7 @@ 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)) > @@ -206,7 +221,8 @@ 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; > @@ -248,9 +264,9 @@ 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); > } > > /** > @@ -315,7 +331,7 @@ 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; > @@ -332,7 +348,7 @@ 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; > > -- Julien Thierry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel