From 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 2 Sep 2026 15:31:14 -0700 Subject: treewide: refresh kmalloc_obj() conversions This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook --- Documentation/virt/paravirt_ops.rst | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/virt/paravirt_ops.rst (limited to 'Documentation/virt/paravirt_ops.rst') diff --git a/Documentation/virt/paravirt_ops.rst b/Documentation/virt/paravirt_ops.rst new file mode 100644 index 000000000..62d867e0d --- /dev/null +++ b/Documentation/virt/paravirt_ops.rst @@ -0,0 +1,35 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +Paravirt_ops +============ + +Linux provides support for different hypervisor virtualization technologies. +Historically, different binary kernels would be required in order to support +different hypervisors; this restriction was removed with pv_ops. +Linux pv_ops is a virtualization API which enables support for different +hypervisors. It allows each hypervisor to override critical operations and +allows a single kernel binary to run on all supported execution environments +including native machine -- without any hypervisors. + +pv_ops provides a set of function pointers which represent operations +corresponding to low-level critical instructions and high-level +functionalities in various areas. pv_ops allows for optimizations at run +time by enabling binary patching of the low-level critical operations +at boot time. + +pv_ops operations are classified into three categories: + +- simple indirect call + These operations correspond to high-level functionality where it is + known that the overhead of indirect call isn't very important. + +- indirect call which allows optimization with binary patch + Usually these operations correspond to low-level critical instructions. They + are called frequently and are performance critical. The overhead is + very important. + +- a set of macros for hand written assembly code + Hand written assembly codes (.S files) also need paravirtualization + because they include sensitive instructions or some code paths in + them are very performance critical. -- cgit v1.3.1