Re: [PATCH v10 06/17] Xen: ARM: Add support for mapping platform device mmio

From: Shannon Zhao <zhaoshenglong@huawei.com>
To: Julien Grall <julien.grall@arm.com>,
	Shannon Zhao <shannon.zhao@linaro.org>,
	<linux-arm-kernel@lists.infradead.org>, <sstabellini@kernel.org>
Cc: <david.vrabel@citrix.com>, <devicetree@vger.kernel.org>,
	<linux-efi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<catalin.marinas@arm.com>, <will.deacon@arm.com>,
	<peter.huangpeng@huawei.com>, <xen-devel@lists.xen.org>
Subject: Re: [PATCH v10 06/17] Xen: ARM: Add support for mapping platform device mmio
Date: Thu, 7 Apr 2016 09:37:01 +0800	[thread overview]
Message-ID: <5705B9BD.1020403@huawei.com> (raw)
In-Reply-To: <5704FE2C.5000902@arm.com>


On 2016/4/6 20:16, Julien Grall wrote:
>> +            gpfns[j] = XEN_PFN_DOWN(r->start) + j;
>> +            idxs[j] = XEN_PFN_DOWN(r->start) + j;
>> +        }
>> +
>> +        xatp.domid = DOMID_SELF;
>> +        xatp.size = nr;
>> +        xatp.space = XENMAPSPACE_dev_mmio;
>> +
>> +        set_xen_guest_handle(xatp.gpfns, gpfns);
>> +        set_xen_guest_handle(xatp.idxs, idxs);
>> +        set_xen_guest_handle(xatp.errs, errs);
>> +
>> +        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
>> +        kfree(gpfns);
>> +        kfree(idxs);
>> +        kfree(errs);
>> +        if (rc)
>> +            return rc;
> 
> Shouldn't we redo the mapping if the hypercall fails?
Hmm, why? If it fails again when we redo the mapping, what should we do
then? Redo again?
I think if it fails at the first time it will always fail no matter how
many times we do.

Thanks,
-- 
Shannon