linux-kernel - Re: [RESEND PATCH v2] iommu/amd: Fix extended features logging

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Date:   Wed, 12 May 2021 21:55:14 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Alexander Monakov <amonakov@...ras.ru>
Cc:     Joerg Roedel <jroedel@...e.de>,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH v2] iommu/amd: Fix extended features logging



Am 04.05.21 um 12:22 schrieb Alexander Monakov:
> print_iommu_info prints the EFR register and then the decoded list of
> features on a separate line:
> 
> pci 0000:00:00.2: AMD-Vi: Extended features (0x206d73ef22254ade):
>   PPR X2APIC NX GT IA GA PC GA_vAPIC
> 
> The second line is emitted via 'pr_cont', which causes it to have a
> different ('warn') loglevel compared to the previous line ('info').
> 
> Commit 9a295ff0ffc9 attempted to rectify this by removing the newline
> from the pci_info format string, but this doesn't work, as pci_info
> calls implicitly append a newline anyway.
> 
> Printing the decoded features on the same line would make it quite long.
> Instead, change pci_info() to pr_info() to omit PCI bus location info,
> which is also shown in the preceding message. This results in:
> 
> pci 0000:00:00.2: AMD-Vi: Found IOMMU cap 0x40
> AMD-Vi: Extended features (0x206d73ef22254ade): PPR X2APIC NX GT IA GA PC GA_vAPIC
> AMD-Vi: Interrupt remapping enabled
> 
> Fixes: 9a295ff0ffc9 ("iommu/amd: Print extended features in one line to fix divergent log levels")
> Link: https://lore.kernel.org/lkml/alpine.LNX.2.20.13.2104112326460.11104@monopod.intra.ispras.ru
> Signed-off-by: Alexander Monakov <amonakov@...ras.ru>
> Cc: Paul Menzel <pmenzel@...gen.mpg.de>
> Cc: Joerg Roedel <jroedel@...e.de>
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> Cc: iommu@...ts.linux-foundation.org
> ---
>   drivers/iommu/amd/init.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> index 429a4baa3aee..8f0eb865119a 100644
> --- a/drivers/iommu/amd/init.c
> +++ b/drivers/iommu/amd/init.c
> @@ -1954,8 +1954,8 @@ static void print_iommu_info(void)
>   		pci_info(pdev, "Found IOMMU cap 0x%x\n", iommu->cap_ptr);
>   
>   		if (iommu->cap & (1 << IOMMU_CAP_EFR)) {
> -			pci_info(pdev, "Extended features (%#llx):",
> -				 iommu->features);
> +			pr_info("Extended features (%#llx):", iommu->features);
> +
>   			for (i = 0; i < ARRAY_SIZE(feat_str); ++i) {
>   				if (iommu_feature(iommu, (1ULL << i)))
>   					pr_cont(" %s", feat_str[i]);
> 
> base-commit: 9f4ad9e425a1d3b6a34617b8ea226d56a119a717

Reviewed-by: Paul Menzel <pmenzel@...gen.mpg.de>


Kind regards,

Paul