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Thu, 20 May 2021 06:09:42 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3030.oracle.com with ESMTP id 38meegpt7w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 May 2021 06:09:42 +0000 Received: from aserp3030.oracle.com (aserp3030.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 14K699cJ089457; Thu, 20 May 2021 06:09:41 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 38meegpt7g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 May 2021 06:09:41 +0000 Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 14K69b6S010834; Thu, 20 May 2021 06:09:38 GMT Received: from kadam (/41.212.42.34) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 19 May 2021 23:09:37 -0700 Date: Thu, 20 May 2021 09:09:24 +0300 From: Dan Carpenter To: Anup Patel Cc: Palmer Dabbelt , Palmer Dabbelt , Paul Walmsley , Albert Ou , Paolo Bonzini , Jonathan Corbet , Greg Kroah-Hartman , Alexander Graf , Atish Patra , Alistair Francis , Damien Le Moal , Anup Patel , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH v18 14/18] RISC-V: KVM: Implement ONE REG interface for FP registers Message-ID: <20210520060924.GD1955@kadam> References: <20210519033553.1110536-1-anup.patel@wdc.com> <20210519033553.1110536-15-anup.patel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210519033553.1110536-15-anup.patel@wdc.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-ORIG-GUID: 9oEaeiTajIB3mCxzFbzpy6mDX4kz6VAg X-Proofpoint-GUID: 9oEaeiTajIB3mCxzFbzpy6mDX4kz6VAg X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9989 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 priorityscore=1501 impostorscore=0 suspectscore=0 clxscore=1015 adultscore=0 bulkscore=0 phishscore=0 spamscore=0 malwarescore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105200050 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, May 19, 2021 at 09:05:49AM +0530, Anup Patel wrote: > +static int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu, > + const struct kvm_one_reg *reg, > + unsigned long rtype) > +{ > + struct kvm_cpu_context *cntx = &vcpu->arch.guest_context; > + unsigned long isa = vcpu->arch.isa; > + unsigned long __user *uaddr = > + (unsigned long __user *)(unsigned long)reg->addr; > + unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK | > + KVM_REG_SIZE_MASK | > + rtype); > + void *reg_val; > + > + if ((rtype == KVM_REG_RISCV_FP_F) && > + riscv_isa_extension_available(&isa, f)) { > + if (KVM_REG_SIZE(reg->id) != sizeof(u32)) > + return -EINVAL; > + if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr)) > + reg_val = &cntx->fp.f.fcsr; > + else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) && > + reg_num <= KVM_REG_RISCV_FP_F_REG(f[31])) > + reg_val = &cntx->fp.f.f[reg_num]; > + else > + return -EINVAL; > + } else if ((rtype == KVM_REG_RISCV_FP_D) && > + riscv_isa_extension_available(&isa, d)) { > + if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) { > + if (KVM_REG_SIZE(reg->id) != sizeof(u32)) > + return -EINVAL; > + reg_val = &cntx->fp.d.fcsr; > + } else if ((KVM_REG_RISCV_FP_D_REG(f[0]) <= reg_num) && > + reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) { > + if (KVM_REG_SIZE(reg->id) != sizeof(u64)) > + return -EINVAL; > + reg_val = &cntx->fp.d.f[reg_num]; > + } else > + return -EINVAL; > + } else > + return -EINVAL; > + > + if (copy_from_user(reg_val, uaddr, KVM_REG_SIZE(reg->id))) ^^^^^^^ It sort of bothers me that if this copy fails then we have no idea what garbage is in reg_val. It would be nicer to copy it to a temporary buffer and then memcpy it when we know it's going succeed. > + return -EFAULT; > + > + return 0; > +} regards, dan carpenter