bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 113 insertions, 0 deletions

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
new file mode 100644
index 000000000..aa11bcefd
--- /dev/null
+++ b/drivers/hv/Kconfig
@@ -0,0 +1,113 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menu "Microsoft Hyper-V guest support"
+
+config HYPERV
+	bool "Microsoft Hyper-V core hypervisor support"
+	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
+		|| (ARM64 && !CPU_BIG_ENDIAN)
+	select PARAVIRT
+	select X86_HV_CALLBACK_VECTOR if X86
+	select OF_EARLY_FLATTREE if OF
+	select IRQ_MSI_LIB if X86
+	help
+	  Select this option to run Linux as a Hyper-V client operating
+	  system.
+
+config HYPERV_VTL_MODE
+	bool "Enable Linux to boot in VTL context"
+	depends on (X86_64 && HAVE_STATIC_CALL) || ARM64
+	depends on HYPERV
+	depends on SMP
+	default n
+	help
+	  Virtual Secure Mode (VSM) is a set of hypervisor capabilities and
+	  enlightenments offered to host and guest partitions which enables
+	  the creation and management of new security boundaries within
+	  operating system software.
+
+	  VSM achieves and maintains isolation through Virtual Trust Levels
+	  (VTLs). Virtual Trust Levels are hierarchical, with higher levels
+	  being more privileged than lower levels. VTL0 is the least privileged
+	  level, and currently only other level supported is VTL2.
+
+	  Select this option to build a Linux kernel to run at a VTL other than
+	  the normal VTL0, which currently is only VTL2.  This option
+	  initializes the kernel to run in VTL2, and adds the ability to boot
+	  secondary CPUs directly into 64-bit context as required for VTLs other
+	  than 0.  A kernel built with this option must run at VTL2, and will
+	  not run as a normal guest.
+
+	  If unsure, say N
+
+config HYPERV_TIMER
+	def_bool HYPERV && X86
+
+config HYPERV_UTILS
+	tristate "Microsoft Hyper-V Utilities driver"
+	depends on HYPERV_VMBUS && CONNECTOR && NLS
+	depends on PTP_1588_CLOCK_OPTIONAL
+	help
+	  Select this option to enable the Hyper-V Utilities.
+
+config HYPERV_BALLOON
+	tristate "Microsoft Hyper-V Balloon driver"
+	depends on HYPERV_VMBUS
+	select PAGE_REPORTING
+	help
+	  Select this option to enable Hyper-V Balloon driver.
+
+config HYPERV_VMBUS
+	tristate "Microsoft Hyper-V VMBus driver"
+	depends on HYPERV
+	default HYPERV
+	select SYSFB if EFI && !HYPERV_VTL_MODE
+	help
+	  Select this option to enable Hyper-V Vmbus driver.
+
+config MSHV_ROOT
+	tristate "Microsoft Hyper-V root partition support"
+	depends on HYPERV && (X86_64 || ARM64)
+	depends on !HYPERV_VTL_MODE
+	# The hypervisor interface operates on 4k pages. Enforcing it here
+	# simplifies many assumptions in the root partition code.
+	# e.g. When withdrawing memory, the hypervisor gives back 4k pages in
+	# no particular order, making it impossible to reassemble larger pages
+	depends on PAGE_SIZE_4KB
+	depends on HYPERV_VMBUS if HYPERV_VMBUS
+	select EVENTFD
+	select VIRT_XFER_TO_GUEST_WORK
+	select HMM_MIRROR
+	select MMU_NOTIFIER
+	default n
+	help
+	  Select this option to enable support for booting and running as root
+	  partition on Microsoft Hyper-V.
+
+	  If unsure, say N.
+
+config MSHV_VTL
+	tristate "Microsoft Hyper-V VTL driver"
+	depends on X86_64 && HYPERV_VTL_MODE
+	depends on HYPERV_VMBUS
+	# Mapping VTL0 memory to a userspace process in VTL2 is supported in OpenHCL.
+	# VTL2 for OpenHCL makes use of Huge Pages to improve performance on VMs,
+	# specially with large memory requirements.
+	depends on TRANSPARENT_HUGEPAGE
+	# MTRRs are controlled by VTL0, and are not specific to individual VTLs.
+	# Therefore, do not attempt to access or modify MTRRs here.
+	depends on !MTRR
+	select CPUMASK_OFFSTACK
+	select VIRT_XFER_TO_GUEST_WORK
+	default n
+	help
+	  Select this option to enable Hyper-V VTL driver support.
+	  This driver provides interfaces for Virtual Machine Manager (VMM) running in VTL2
+	  userspace to create VTLs and partitions, setup and manage VTL0 memory and
+	  allow userspace to make direct hypercalls. This also allows to map VTL0's address
+	  space to a usermode process in VTL2 and supports getting new VMBus messages and channel
+	  events in VTL2.
+
+	  If unsure, say N.
+
+endmenu