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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Thu, 24 Mar 2022 09:31:13 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Borislav Petkov <bp@alien8.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Wed, Mar 23, 2022 at 4:21 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > So this should make at least the most obvious and common ones not go
> > unnoticed.
> 
> Ack. I'm actually surprised people use "defconfig". It's kind of
> pointless and unreal on x86 where there is no realistic "default". I'm
> sorry it exists at all.
>
> But since people clearly use it - presumably for testing - I very much 
> think it should have WERROR on.

Hm, I never saw the warning you got - I test 8 main configs on x86:

 - {x86_64|i386} X {allnoconfig,defconfig,allmodconfig,allyesconfig}

Plus an unlimited number of randconfigs. Normally no warnings are permitted 
in any of the 8 base configs - regardless of whether WERROR is enabled or 
not.

I'm using x86 defconfig as:

 - A quick to build, bootable config (on KVM) with settings that are 
   supposed to be pretty close to how the bigger x86 distros set up their 
   kernels. Defconfig builds ~5x faster than allmodconfig.

 - Reference config for kernel bloat measurements. Empirically the text 
   section of its vmlinux shrinks roughly as well as a full distro kernel 
   build - with a fraction of a build time.

 - Developer reference point & minimal test requirements. If an incoming 
   patch doesn't even build on defconfig that's a serious red flag.

 - I also use defconfig when applying individual patches or series when I 
   cannot do a full allmodconfig build for the entire series.

 - I also have kconfig scripts that enable all of the (practical...) debug 
   options in a kernel. So I often boot x86-64 defconfig, then 
   defconfig+fulldebug. Again this is much faster & practical to do than 
   allmod or allyes configs.

But beyond the WERROR oversight, bitrot has gotten to defconfig a bit - see 
attached patch. My test scripts usually enable these - but it's better to 
formalize it.

Anyway, I've put Boris's patch into x86/urgent with your Acked-by, then my 
bigger defconfig cleanup patch. We'll send a pull request for these ASAP, 
plus the local_lock cleanup once there's consensus.

Thanks,

	Ingo

================>

From: Ingo Molnar <mingo@kernel.org>
Date: Thu, 24 Mar 2022 09:18:36 +0100
Subject: [PATCH] x86/config: Make the x86 defconfigs a bit more usable

 - Use 'make savedefconfig' to refresh & regenerate the files
 - Add in KVM boot enablers
 - Enable the cgroup features most distros rely on

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/configs/i386_defconfig   | 50 ++++++++++++++++++++++++++-------------
 arch/x86/configs/x86_64_defconfig | 38 +++++++++++++++++++++--------
 2 files changed, 62 insertions(+), 26 deletions(-)

diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 4b2085243aa3..fde771df72cc 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -1,5 +1,7 @@
+CONFIG_WERROR=y
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
+CONFIG_USELIB=y
 CONFIG_AUDIT=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
@@ -11,23 +13,30 @@ CONFIG_TASK_XACCT=y
 CONFIG_TASK_IO_ACCOUNTING=y
 CONFIG_LOG_BUF_SHIFT=18
 CONFIG_CGROUPS=y
+CONFIG_BLK_CGROUP=y
 CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_PIDS=y
+CONFIG_CGROUP_RDMA=y
 CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_HUGETLB=y
 CONFIG_CPUSETS=y
+CONFIG_CGROUP_DEVICE=y
 CONFIG_CGROUP_CPUACCT=y
+CONFIG_CGROUP_PERF=y
+CONFIG_CGROUP_MISC=y
+CONFIG_CGROUP_DEBUG=y
 CONFIG_BLK_DEV_INITRD=y
+CONFIG_KALLSYMS_ALL=y
 # CONFIG_COMPAT_BRK is not set
 CONFIG_PROFILING=y
-# CONFIG_64BIT is not set
 CONFIG_SMP=y
-CONFIG_X86_GENERIC=y
-CONFIG_HPET_TIMER=y
+CONFIG_HYPERVISOR_GUEST=y
+CONFIG_PARAVIRT=y
+CONFIG_NR_CPUS=8
 CONFIG_X86_REROUTE_FOR_BROKEN_BOOT_IRQS=y
-CONFIG_X86_REBOOTFIXUPS=y
 CONFIG_MICROCODE_AMD=y
 CONFIG_X86_MSR=y
 CONFIG_X86_CPUID=y
-CONFIG_HIGHPTE=y
 CONFIG_X86_CHECK_BIOS_CORRUPTION=y
 # CONFIG_MTRR_SANITIZER is not set
 CONFIG_EFI=y
@@ -43,12 +52,15 @@ CONFIG_ACPI_BGRT=y
 CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
 CONFIG_CPU_FREQ_GOV_ONDEMAND=y
 CONFIG_X86_ACPI_CPUFREQ=y
-CONFIG_EFI_VARS=y
 CONFIG_KPROBES=y
 CONFIG_JUMP_LABEL=y
+CONFIG_COMPAT_32BIT_TIME=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
+CONFIG_BLK_CGROUP_IOLATENCY=y
+CONFIG_BLK_CGROUP_IOCOST=y
+CONFIG_BLK_CGROUP_IOPRIO=y
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y
@@ -103,12 +115,16 @@ CONFIG_IP6_NF_FILTER=y
 CONFIG_IP6_NF_TARGET_REJECT=y
 CONFIG_IP6_NF_MANGLE=y
 CONFIG_NET_SCHED=y
+CONFIG_NET_CLS_CGROUP=y
 CONFIG_NET_EMATCH=y
 CONFIG_NET_CLS_ACT=y
+CONFIG_CGROUP_NET_PRIO=y
 CONFIG_CFG80211=y
 CONFIG_MAC80211=y
 CONFIG_MAC80211_LEDS=y
 CONFIG_RFKILL=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
 CONFIG_PCI=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_PCI_MSI=y
@@ -119,13 +135,16 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_DEBUG_DEVRES=y
 CONFIG_CONNECTOR=y
+CONFIG_EFI_VARS=y
+CONFIG_EFI_CAPSULE_LOADER=y
 CONFIG_BLK_DEV_LOOP=y
+CONFIG_VIRTIO_BLK=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_BLK_DEV_SR=y
 CONFIG_CHR_DEV_SG=y
 CONFIG_SCSI_CONSTANTS=y
 CONFIG_SCSI_SPI_ATTRS=y
-# CONFIG_SCSI_LOWLEVEL is not set
+CONFIG_SCSI_VIRTIO=y
 CONFIG_ATA=y
 CONFIG_SATA_AHCI=y
 CONFIG_ATA_PIIX=y
@@ -143,6 +162,7 @@ CONFIG_MACINTOSH_DRIVERS=y
 CONFIG_MAC_EMUMOUSEBTN=y
 CONFIG_NETDEVICES=y
 CONFIG_NETCONSOLE=y
+CONFIG_VIRTIO_NET=y
 CONFIG_BNX2=y
 CONFIG_TIGON3=y
 CONFIG_NET_TULIP=y
@@ -170,6 +190,7 @@ CONFIG_SERIAL_8250_SHARE_IRQ=y
 CONFIG_SERIAL_8250_DETECT_IRQ=y
 CONFIG_SERIAL_8250_RSA=y
 CONFIG_SERIAL_NONSTANDARD=y
+CONFIG_VIRTIO_CONSOLE=y
 CONFIG_HW_RANDOM=y
 CONFIG_NVRAM=y
 CONFIG_HPET=y
@@ -181,12 +202,7 @@ CONFIG_AGP_AMD64=y
 CONFIG_AGP_INTEL=y
 CONFIG_DRM=y
 CONFIG_DRM_I915=y
-CONFIG_FB_MODE_HELPERS=y
-CONFIG_FB_TILEBLITTING=y
-CONFIG_FB_EFI=y
-CONFIG_LOGO=y
-# CONFIG_LOGO_LINUX_MONO is not set
-# CONFIG_LOGO_LINUX_VGA16 is not set
+CONFIG_DRM_VIRTIO_GPU=y
 CONFIG_SOUND=y
 CONFIG_SND=y
 CONFIG_SND_HRTIMER=y
@@ -219,6 +235,8 @@ CONFIG_USB_STORAGE=y
 CONFIG_RTC_CLASS=y
 # CONFIG_RTC_HCTOSYS is not set
 CONFIG_DMADEVICES=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_INPUT=y
 CONFIG_EEEPC_LAPTOP=y
 CONFIG_EXT4_FS=y
 CONFIG_EXT4_FS_POSIX_ACL=y
@@ -240,6 +258,7 @@ CONFIG_NFS_FS=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
+CONFIG_9P_FS=y
 CONFIG_NLS_DEFAULT="utf8"
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
@@ -251,15 +270,14 @@ CONFIG_SECURITY_SELINUX=y
 CONFIG_SECURITY_SELINUX_BOOTPARAM=y
 CONFIG_SECURITY_SELINUX_DISABLE=y
 CONFIG_PRINTK_TIME=y
+CONFIG_FRAME_WARN=1024
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_STACK_USAGE=y
-CONFIG_DEBUG_STACKOVERFLOW=y
 # CONFIG_SCHED_DEBUG is not set
 CONFIG_SCHEDSTATS=y
 CONFIG_BLK_DEV_IO_TRACE=y
 CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
 CONFIG_EARLY_PRINTK_DBGP=y
 CONFIG_DEBUG_BOOT_PARAMS=y
-CONFIG_KALLSYMS_ALL=y
-CONFIG_WERROR=y
+CONFIG_UNWINDER_FRAME_POINTER=y
diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
index 38c52e4eb30b..69784505a7a8 100644
--- a/arch/x86/configs/x86_64_defconfig
+++ b/arch/x86/configs/x86_64_defconfig
@@ -1,3 +1,4 @@
+CONFIG_WERROR=y
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_AUDIT=y
@@ -11,14 +12,25 @@ CONFIG_TASK_XACCT=y
 CONFIG_TASK_IO_ACCOUNTING=y
 CONFIG_LOG_BUF_SHIFT=18
 CONFIG_CGROUPS=y
+CONFIG_BLK_CGROUP=y
 CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_PIDS=y
+CONFIG_CGROUP_RDMA=y
 CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_HUGETLB=y
 CONFIG_CPUSETS=y
+CONFIG_CGROUP_DEVICE=y
 CONFIG_CGROUP_CPUACCT=y
+CONFIG_CGROUP_PERF=y
+CONFIG_CGROUP_MISC=y
+CONFIG_CGROUP_DEBUG=y
 CONFIG_BLK_DEV_INITRD=y
+CONFIG_KALLSYMS_ALL=y
 # CONFIG_COMPAT_BRK is not set
 CONFIG_PROFILING=y
 CONFIG_SMP=y
+CONFIG_HYPERVISOR_GUEST=y
+CONFIG_PARAVIRT=y
 CONFIG_X86_REROUTE_FOR_BROKEN_BOOT_IRQS=y
 CONFIG_MICROCODE_AMD=y
 CONFIG_X86_MSR=y
@@ -41,12 +53,14 @@ CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
 CONFIG_CPU_FREQ_GOV_ONDEMAND=y
 CONFIG_X86_ACPI_CPUFREQ=y
 CONFIG_IA32_EMULATION=y
-CONFIG_EFI_VARS=y
 CONFIG_KPROBES=y
 CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
+CONFIG_BLK_CGROUP_IOLATENCY=y
+CONFIG_BLK_CGROUP_IOCOST=y
+CONFIG_BLK_CGROUP_IOPRIO=y
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y
@@ -101,12 +115,16 @@ CONFIG_IP6_NF_FILTER=y
 CONFIG_IP6_NF_TARGET_REJECT=y
 CONFIG_IP6_NF_MANGLE=y
 CONFIG_NET_SCHED=y
+CONFIG_NET_CLS_CGROUP=y
 CONFIG_NET_EMATCH=y
 CONFIG_NET_CLS_ACT=y
+CONFIG_CGROUP_NET_PRIO=y
 CONFIG_CFG80211=y
 CONFIG_MAC80211=y
 CONFIG_MAC80211_LEDS=y
 CONFIG_RFKILL=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
 CONFIG_PCI=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_HOTPLUG_PCI=y
@@ -116,13 +134,15 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_DEBUG_DEVRES=y
 CONFIG_CONNECTOR=y
+CONFIG_EFI_VARS=y
 CONFIG_BLK_DEV_LOOP=y
+CONFIG_VIRTIO_BLK=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_BLK_DEV_SR=y
 CONFIG_CHR_DEV_SG=y
 CONFIG_SCSI_CONSTANTS=y
 CONFIG_SCSI_SPI_ATTRS=y
-# CONFIG_SCSI_LOWLEVEL is not set
+CONFIG_SCSI_VIRTIO=y
 CONFIG_ATA=y
 CONFIG_SATA_AHCI=y
 CONFIG_ATA_PIIX=y
@@ -138,6 +158,7 @@ CONFIG_MACINTOSH_DRIVERS=y
 CONFIG_MAC_EMUMOUSEBTN=y
 CONFIG_NETDEVICES=y
 CONFIG_NETCONSOLE=y
+CONFIG_VIRTIO_NET=y
 CONFIG_TIGON3=y
 CONFIG_NET_TULIP=y
 CONFIG_E100=y
@@ -162,6 +183,7 @@ CONFIG_SERIAL_8250_SHARE_IRQ=y
 CONFIG_SERIAL_8250_DETECT_IRQ=y
 CONFIG_SERIAL_8250_RSA=y
 CONFIG_SERIAL_NONSTANDARD=y
+CONFIG_VIRTIO_CONSOLE=y
 CONFIG_HW_RANDOM=y
 # CONFIG_HW_RANDOM_INTEL is not set
 # CONFIG_HW_RANDOM_AMD is not set
@@ -175,12 +197,7 @@ CONFIG_AGP_AMD64=y
 CONFIG_AGP_INTEL=y
 CONFIG_DRM=y
 CONFIG_DRM_I915=y
-CONFIG_FB_MODE_HELPERS=y
-CONFIG_FB_TILEBLITTING=y
-CONFIG_FB_EFI=y
-CONFIG_LOGO=y
-# CONFIG_LOGO_LINUX_MONO is not set
-# CONFIG_LOGO_LINUX_VGA16 is not set
+CONFIG_DRM_VIRTIO_GPU=y
 CONFIG_SOUND=y
 CONFIG_SND=y
 CONFIG_SND_HRTIMER=y
@@ -213,6 +230,8 @@ CONFIG_USB_STORAGE=y
 CONFIG_RTC_CLASS=y
 # CONFIG_RTC_HCTOSYS is not set
 CONFIG_DMADEVICES=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_INPUT=y
 CONFIG_EEEPC_LAPTOP=y
 CONFIG_AMD_IOMMU=y
 CONFIG_INTEL_IOMMU=y
@@ -237,6 +256,7 @@ CONFIG_NFS_FS=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
+CONFIG_9P_FS=y
 CONFIG_NLS_DEFAULT="utf8"
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
@@ -257,5 +277,3 @@ CONFIG_BLK_DEV_IO_TRACE=y
 CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
 CONFIG_EARLY_PRINTK_DBGP=y
 CONFIG_DEBUG_BOOT_PARAMS=y
-CONFIG_KALLSYMS_ALL=y
-CONFIG_WERROR=y