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Tue, 12 Jul 2022 08:25:18 +0100 Date: Tue, 12 Jul 2022 08:25:09 +0100 Message-ID: <87edyqlrmy.wl-maz@kernel.org> From: Marc Zyngier To: Reiji Watanabe Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Linux ARM , Schspa Shi , kernel-team@android.com, Oliver Upton Subject: Re: [PATCH 05/19] KVM: arm64: Consolidate sysreg userspace accesses In-Reply-To: References: <20220706164304.1582687-1-maz@kernel.org> <20220706164304.1582687-6-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.104.136.29 X-SA-Exim-Rcpt-To: reijiw@google.com, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, schspa@gmail.com, kernel-team@android.com, oliver.upton@linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220712_002524_901623_7D73DA54 X-CRM114-Status: GOOD ( 20.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Reiji, On Sat, 09 Jul 2022 07:55:08 +0100, Reiji Watanabe wrote: > > Hi Marc, [...] > > @@ -2854,17 +2794,28 @@ static int demux_c15_set(u64 id, void __user *uaddr) > > int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, > > const struct sys_reg_desc table[], unsigned int num) > > { > > - void __user *uaddr = (void __user *)(unsigned long)reg->addr; > > + u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr; > > const struct sys_reg_desc *r; > > + u64 val; > > + int ret; > > > > r = id_to_sys_reg_desc(vcpu, reg->id, table, num); > > if (!r) > > return -ENOENT; > > > > - if (r->get_user) > > - return (r->get_user)(vcpu, r, reg, uaddr); > > + if (r->get_user) { > > + ret = (r->get_user)(vcpu, r, &val); > > + } else { > > + val = __vcpu_sys_reg(vcpu, r->reg); > > + ret = 0; > > + } > > + > > + if (!ret) { > > + if (put_user(val, uaddr)) > > + ret = -EFAULT; > > Nit: Since put_user() returns -EFAULT when it fails, > we can simply set 'ret' to the return value from put_user(). Indeed. I've now reworked all the instances of this that survive the incremental rework. Thanks for the suggestion. > (same for get_user()) This one is a harder sell, as get_user() usually occurs at the beginning of the function, without a preexisting error context. > > Reviewed-by: Reiji Watanabe > > I like this fix! Thanks! M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel