linux-kernel - Re: [RFC KERNEL PATCH v2 2/3] xen/pvh: Unmask irq for passthrough device in PVH dom0

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:   Tue, 5 Dec 2023 07:03:30 +0000
From:   "Chen, Jiqian" <Jiqian.Chen@....com>
To:     Thomas Gleixner <tglx@...utronix.de>
CC:     Stefano Stabellini <sstabellini@...nel.org>,
        Juergen Gross <jgross@...e.com>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Roger Pau Monné <roger.pau@...rix.com>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "Stabellini, Stefano" <stefano.stabellini@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Hildebrand, Stewart" <Stewart.Hildebrand@....com>,
        "Ragiadakou, Xenia" <Xenia.Ragiadakou@....com>,
        "Huang, Honglei1" <Honglei1.Huang@....com>,
        "Zhang, Julia" <Julia.Zhang@....com>,
        "Huang, Ray" <Ray.Huang@....com>,
        "Chen, Jiqian" <Jiqian.Chen@....com>
Subject: Re: [RFC KERNEL PATCH v2 2/3] xen/pvh: Unmask irq for passthrough
 device in PVH dom0

Hi Thomas Gleixner,

Thank you for review, and you are right, it seems more like a XEN internal issue. We are discussing it and maybe will fix it in Xen code next version.

On 2023/12/4 16:13, Thomas Gleixner wrote:
> On Fri, Nov 24 2023 at 18:31, Jiqian Chen wrote:
>> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
>> index 5a96b6c66c07..b83d02bcc76c 100644
>> --- a/drivers/xen/xen-pciback/pci_stub.c
>> +++ b/drivers/xen/xen-pciback/pci_stub.c
>> @@ -357,6 +357,7 @@ static int pcistub_match(struct pci_dev *dev)
>>  static int pcistub_init_device(struct pci_dev *dev)
>>  {
>>  	struct xen_pcibk_dev_data *dev_data;
>> +	struct irq_desc *desc = NULL;
>>  	int err = 0;
>>  
>>  	dev_dbg(&dev->dev, "initializing...\n");
>> @@ -399,6 +400,12 @@ static int pcistub_init_device(struct pci_dev *dev)
>>  	if (err)
>>  		goto config_release;
>>  
>> +	if (xen_initial_domain() && xen_pvh_domain()) {
>> +		if (dev->irq <= 0 || !(desc = irq_to_desc(dev->irq)))
> 
> Driver code has absolutely no business to access irq_desc.
> 
>> +			goto config_release;
>> +		unmask_irq(desc);
> 
> Or to invoke any internal function.
> 
>> --- a/kernel/irq/chip.c
>> +++ b/kernel/irq/chip.c
>> @@ -439,6 +439,7 @@ void unmask_irq(struct irq_desc *desc)
>>  		irq_state_clr_masked(desc);
>>  	}
>>  }
>> +EXPORT_SYMBOL_GPL(unmask_irq);
> 
> Not going to happen.
> 
>> --- a/kernel/irq/irqdesc.c
>> +++ b/kernel/irq/irqdesc.c
>> @@ -380,7 +380,7 @@ struct irq_desc *irq_to_desc(unsigned int irq)
>>  {
>>  	return mtree_load(&sparse_irqs, irq);
>>  }
>> -#ifdef CONFIG_KVM_BOOK3S_64_HV_MODULE
>> +#if defined CONFIG_KVM_BOOK3S_64_HV_MODULE || defined CONFIG_XEN_PVH
> 
> Neither that.
> 
> This all smells badly like a XEN internal issue and we are not going to
> hack around it by exposing interrupt internals.
> 
> Thanks,
> 
>         tglx

-- 
Best regards,
Jiqian Chen.