linux-kernel - Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries

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Message-ID: <c0f992fd-aaad-9250-2103-fa290db46387@google.com>
Date:   Wed, 8 Jan 2020 12:35:41 -0500
From:   Barret Rhoden <brho@...gle.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Joerg Roedel <joro@...tes.org>,
        Yian Chen <yian.chen@...el.com>,
        Sohil Mehta <sohil.mehta@...el.com>
Cc:     iommu@...ts.linux-foundation.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] iommu/vt-d: skip invalid RMRR entries

On 1/7/20 8:27 PM, Lu Baolu wrote:
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index a8bb458845bc..32c3c6338a3d 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -4315,13 +4315,25 @@ static void __init init_iommu_pm_ops(void)
>>   static inline void init_iommu_pm_ops(void) {}
>>   #endif    /* CONFIG_PM */
>> +static int rmrr_validity_check(struct acpi_dmar_reserved_memory *rmrr)
>> +{
>> +    if ((rmrr->base_address & PAGE_MASK) ||
>> +        (rmrr->end_address <= rmrr->base_address) ||
>> +        ((rmrr->end_address - rmrr->base_address + 1) & PAGE_MASK)) {
>> +        pr_err(FW_BUG "Broken RMRR base: %#018Lx end: %#018Lx\n",
>> +               rmrr->base_address, rmrr->end_address);
> 
> Since you will WARN_TAINT below, do you still want an error message
> here?

I'm fine either way.

I put it in since arch_rmrr_sanity_check() also has a pr_err():

	pr_err(FW_BUG "No firmware reserved region can cover this RMRR
                [%#018Lx-%#018Lx], contact BIOS vendor for fixes\n",
                start, end - 1);

Thanks,

Barret