[PATCH] iommu/amd: Print extended features in one line to fix divergent log levels

[PATCH] iommu/amd: Print extended features in one line to fix divergent log levels

[Paul Menzel]

Currently, Linux logs the two messages below.

    [    0.979142] pci 0000:00:00.2: AMD-Vi: Extended features (0xf77ef22294ada):
    [    0.979546]  PPR NX GT IA GA PC GA_vAPIC

The log level of these lines differs though. The first one has level
*info*, while the second has level *warn*, which is confusing.

    $ dmesg -T --level=info | grep "Extended features"
    [Tue Jun 16 21:46:58 2020] pci 0000:00:00.2: AMD-Vi: Extended features (0xf77ef22294ada):
    $ dmesg -T --level=warn | grep "PPR"
    [Tue Jun 16 21:46:58 2020]  PPR NX GT IA GA PC GA_vAPIC

The problem is, that commit 3928aa3f57 ("iommu/amd: Detect and enable
guest vAPIC support") introduced a newline, causing `pr_cont()`, used to
print the features, to default back to the default log level.

    /**
     * pr_cont - Continues a previous log message in the same line.
     * @fmt: format string
     * @...: arguments for the format string
     *
     * This macro expands to a printk with KERN_CONT loglevel. It should only be
     * used when continuing a log message with no newline ('\n') enclosed. Otherwise
     * it defaults back to KERN_DEFAULT loglevel.
     */
    #define pr_cont(fmt, ...) \
            printk(KERN_CONT fmt, ##__VA_ARGS__)

So, remove the line break, so only one line is logged.

Fixes: 3928aa3f57 ("iommu/amd: Detect and enable guest vAPIC support")
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
---
 drivers/iommu/amd_iommu_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 5b81fd16f5faf8..8d9b2c94178c43 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1844,7 +1844,7 @@ static void print_iommu_info(void)
 		pci_info(pdev, "Found IOMMU cap 0x%hx\n", iommu->cap_ptr);
 
 		if (iommu->cap & (1 << IOMMU_CAP_EFR)) {
-			pci_info(pdev, "Extended features (%#llx):\n",
+			pci_info(pdev, "Extended features (%#llx):",
 				 iommu->features);
 			for (i = 0; i < ARRAY_SIZE(feat_str); ++i) {
 				if (iommu_feature(iommu, (1ULL << i)))
-- 
2.26.2

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Re: [PATCH] iommu/amd: Print extended features in one line to fix divergent log levels

[Suravee Suthikulpanit]

On 6/17/20 5:04 AM, Paul Menzel wrote:
> Currently, Linux logs the two messages below.
> 
>      [    0.979142] pci 0000:00:00.2: AMD-Vi: Extended features (0xf77ef22294ada):
>      [    0.979546]  PPR NX GT IA GA PC GA_vAPIC
> 
> The log level of these lines differs though. The first one has level
> *info*, while the second has level *warn*, which is confusing.
> 
>      $ dmesg -T --level=info | grep "Extended features"
>      [Tue Jun 16 21:46:58 2020] pci 0000:00:00.2: AMD-Vi: Extended features (0xf77ef22294ada):
>      $ dmesg -T --level=warn | grep "PPR"
>      [Tue Jun 16 21:46:58 2020]  PPR NX GT IA GA PC GA_vAPIC
> 
> The problem is, that commit 3928aa3f57 ("iommu/amd: Detect and enable
> guest vAPIC support") introduced a newline, causing `pr_cont()`, used to
> print the features, to default back to the default log level.
> 
>      /**
>       * pr_cont - Continues a previous log message in the same line.
>       * @fmt: format string
>       * @...: arguments for the format string
>       *
>       * This macro expands to a printk with KERN_CONT loglevel. It should only be
>       * used when continuing a log message with no newline ('\n') enclosed. Otherwise
>       * it defaults back to KERN_DEFAULT loglevel.
>       */
>      #define pr_cont(fmt, ...) \
>              printk(KERN_CONT fmt, ##__VA_ARGS__)
> 
> So, remove the line break, so only one line is logged.
> 
> Fixes: 3928aa3f57 ("iommu/amd: Detect and enable guest vAPIC support")
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> Cc: iommu@lists.linux-foundation.org
> Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
> ---
>   drivers/iommu/amd_iommu_init.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index 5b81fd16f5faf8..8d9b2c94178c43 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -1844,7 +1844,7 @@ static void print_iommu_info(void)
>   		pci_info(pdev, "Found IOMMU cap 0x%hx\n", iommu->cap_ptr);
>   
>   		if (iommu->cap & (1 << IOMMU_CAP_EFR)) {
> -			pci_info(pdev, "Extended features (%#llx):\n",
> +			pci_info(pdev, "Extended features (%#llx):",
>   				 iommu->features);
>   			for (i = 0; i < ARRAY_SIZE(feat_str); ++i) {
>   				if (iommu_feature(iommu, (1ULL << i)))
> 

Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>

Thanks,
Suravee
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Re: [PATCH] iommu/amd: Print extended features in one line to fix divergent log levels

[Jörg Rödel]

On Wed, Jun 17, 2020 at 12:04:20AM +0200, Paul Menzel wrote:
>  drivers/iommu/amd_iommu_init.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.
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