linux-kernel - RE: [PATCH v2 15/15] Drivers: hv: Add modules to expose /dev/mshv to VMMs running on Hyper-V

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 21 Aug 2023 18:18:00 +0000
From:   Saurabh Singh Sengar <ssengar@...rosoft.com>
To:     Nuno Das Neves <nunodasneves@...ux.microsoft.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
CC:     "patches@...ts.linux.dev" <patches@...ts.linux.dev>,
        "Michael Kelley (LINUX)" <mikelley@...rosoft.com>,
        KY Srinivasan <kys@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Dexuan Cui <decui@...rosoft.com>,
        "apais@...ux.microsoft.com" <apais@...ux.microsoft.com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        "ssengar@...ux.microsoft.com" <ssengar@...ux.microsoft.com>,
        MUKESH RATHOR <mukeshrathor@...rosoft.com>,
        "stanislav.kinsburskiy@...il.com" <stanislav.kinsburskiy@...il.com>,
        "jinankjain@...ux.microsoft.com" <jinankjain@...ux.microsoft.com>,
        vkuznets <vkuznets@...hat.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "hpa@...or.com" <hpa@...or.com>,
        "will@...nel.org" <will@...nel.org>,
        "catalin.marinas@....com" <catalin.marinas@....com>
Subject: RE: [PATCH v2 15/15] Drivers: hv: Add modules to expose /dev/mshv to
 VMMs running on Hyper-V



> -----Original Message-----
> From: Nuno Das Neves <nunodasneves@...ux.microsoft.com>
> Sent: Friday, August 18, 2023 3:32 AM
> To: linux-hyperv@...r.kernel.org; linux-kernel@...r.kernel.org;
> x86@...nel.org; linux-arm-kernel@...ts.infradead.org; linux-
> arch@...r.kernel.org
> Cc: patches@...ts.linux.dev; Michael Kelley (LINUX)
> <mikelley@...rosoft.com>; KY Srinivasan <kys@...rosoft.com>;
> wei.liu@...nel.org; Haiyang Zhang <haiyangz@...rosoft.com>; Dexuan Cui
> <decui@...rosoft.com>; apais@...ux.microsoft.com; Tianyu Lan
> <Tianyu.Lan@...rosoft.com>; ssengar@...ux.microsoft.com; MUKESH
> RATHOR <mukeshrathor@...rosoft.com>; stanislav.kinsburskiy@...il.com;
> jinankjain@...ux.microsoft.com; vkuznets <vkuznets@...hat.com>;
> tglx@...utronix.de; mingo@...hat.com; bp@...en8.de;
> dave.hansen@...ux.intel.com; hpa@...or.com; will@...nel.org;
> catalin.marinas@....com
> Subject: [PATCH v2 15/15] Drivers: hv: Add modules to expose /dev/mshv to
> VMMs running on Hyper-V
> 
> Add mshv, mshv_root, and mshv_vtl modules:
> 

<snip>

> +	ret = mshv_set_vp_registers(vp->index, vp->partition->id,
> +				    1, &dispatch_suspend);
> +	if (ret)
> +		pr_err("%s: failed to suspend partition %llu vp %u\n",
> +			__func__, vp->partition->id, vp->index);
> +
> +	return ret;
> +}
> +
> +static int
> +get_vp_signaled_count(struct mshv_vp *vp, u64 *count)
> +{
> +	int ret;
> +	struct hv_register_assoc root_signal_count = {
> +		.name = HV_REGISTER_VP_ROOT_SIGNAL_COUNT,
> +	};
> +
> +	ret = mshv_get_vp_registers(vp->index, vp->partition->id,
> +				    1, &root_signal_count);
> +
> +	if (ret) {
> +		pr_err("%s: failed to get root signal count for partition %llu vp
> %u",
> +			__func__, vp->partition->id, vp->index);
> +		*count = 0;

Have we missed a return here ?
Moreover, the return type of this function is never checked consider
checking it or change it to void.

<snip>

> +
> +/* Retrieve and stash the supported scheduler type */
> +static int __init mshv_retrieve_scheduler_type(void)
> +{
> +	struct hv_input_get_system_property *input;
> +	struct hv_output_get_system_property *output;
> +	unsigned long flags;
> +	u64 status;
> +
> +	local_irq_save(flags);
> +	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> +	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
> +
> +	memset(input, 0, sizeof(*input));
> +	memset(output, 0, sizeof(*output));
> +	input->property_id = HV_SYSTEM_PROPERTY_SCHEDULER_TYPE;
> +
> +	status = hv_do_hypercall(HVCALL_GET_SYSTEM_PROPERTY, input,
> output);
> +	if (!hv_result_success(status)) {
> +		local_irq_restore(flags);
> +		pr_err("%s: %s\n", __func__, hv_status_to_string(status));
> +		return hv_status_to_errno(status);
> +	}
> +
> +	hv_scheduler_type = output->scheduler_type;
> +	local_irq_restore(flags);
> +
> +	pr_info("mshv: hypervisor using %s\n",
> scheduler_type_to_string(hv_scheduler_type));

Nit: In this file we are using two styles of prints, few are appended with
"mshv:" and few with "__func__".  It's better to have a single style
for one module.