linux/arch/powerpc/kernel/firmware.c
Srikar Dronamraju a21d1becaa powerpc: Reintroduce is_kvm_guest() as a fast-path check
Introduce a static branch that would be set during boot if the OS
happens to be a KVM guest. Subsequent checks to see if we are on KVM
will rely on this static branch. This static branch would be used in
vcpu_is_preempted() in a subsequent patch.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202050456.164005-4-srikar@linux.vnet.ibm.com
2020-12-04 01:01:22 +11:00

41 lines
944 B
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Extracted from cputable.c
*
* Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
*
* Modifications for ppc64:
* Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
* Copyright (C) 2005 Stephen Rothwell, IBM Corporation
*/
#include <linux/export.h>
#include <linux/cache.h>
#include <linux/of.h>
#include <asm/firmware.h>
#include <asm/kvm_guest.h>
#ifdef CONFIG_PPC64
unsigned long powerpc_firmware_features __read_mostly;
EXPORT_SYMBOL_GPL(powerpc_firmware_features);
#endif
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
DEFINE_STATIC_KEY_FALSE(kvm_guest);
bool check_kvm_guest(void)
{
struct device_node *hyper_node;
hyper_node = of_find_node_by_path("/hypervisor");
if (!hyper_node)
return false;
if (!of_device_is_compatible(hyper_node, "linux,kvm"))
return false;
static_branch_enable(&kvm_guest);
return true;
}
#endif