ARM: KVM: Add HYP mode entry code (bafc6c2a) · Commits · e / devices / android_kernel_fairphone_FP5

arch/arm/kvm/hyp/Makefile

+1 −0

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		@@ -9,4 +9,5 @@ obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o
		obj-$(CONFIG_KVM_ARM_HOST) += vfp.o
		obj-$(CONFIG_KVM_ARM_HOST) += banked-sr.o
		obj-$(CONFIG_KVM_ARM_HOST) += entry.o
		obj-$(CONFIG_KVM_ARM_HOST) += hyp-entry.o
		obj-$(CONFIG_KVM_ARM_HOST) += switch.o

arch/arm/kvm/hyp/hyp-entry.S

0 → 100644

+157 −0

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		/*
		* Copyright (C) 2012 - Virtual Open Systems and Columbia University
		* Author: Christoffer Dall <c.dall@virtualopensystems.com>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License, version 2, as
		* published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
		*/

		#include <linux/linkage.h>
		#include <asm/kvm_arm.h>
		#include <asm/kvm_asm.h>

		.arch_extension virt

		.text
		.pushsection .hyp.text, "ax"

		.macro load_vcpu reg
		mrc p15, 4, \reg, c13, c0, 2 @ HTPIDR
		.endm

		/********************************************************************
		* Hypervisor exception vector and handlers
		*
		*
		* The KVM/ARM Hypervisor ABI is defined as follows:
		*
		* Entry to Hyp mode from the host kernel will happen _only_ when an HVC
		* instruction is issued since all traps are disabled when running the host
		* kernel as per the Hyp-mode initialization at boot time.
		*
		* HVC instructions cause a trap to the vector page + offset 0x14 (see hyp_hvc
		* below) when the HVC instruction is called from SVC mode (i.e. a guest or the
		* host kernel) and they cause a trap to the vector page + offset 0x8 when HVC
		* instructions are called from within Hyp-mode.
		*
		* Hyp-ABI: Calling HYP-mode functions from host (in SVC mode):
		* Switching to Hyp mode is done through a simple HVC #0 instruction. The
		* exception vector code will check that the HVC comes from VMID==0.
		* - r0 contains a pointer to a HYP function
		* - r1, r2, and r3 contain arguments to the above function.
		* - The HYP function will be called with its arguments in r0, r1 and r2.
		* On HYP function return, we return directly to SVC.
		*
		* Note that the above is used to execute code in Hyp-mode from a host-kernel
		* point of view, and is a different concept from performing a world-switch and
		* executing guest code SVC mode (with a VMID != 0).
		*/

		.align 5
		__hyp_vector:
		.global __hyp_vector
		__kvm_hyp_vector:
		.weak __kvm_hyp_vector

		@ Hyp-mode exception vector
		W(b) hyp_reset
		W(b) hyp_undef
		W(b) hyp_svc
		W(b) hyp_pabt
		W(b) hyp_dabt
		W(b) hyp_hvc
		W(b) hyp_irq
		W(b) hyp_fiq

		.macro invalid_vector label, cause
		.align
		\label: b .
		.endm

		invalid_vector hyp_reset
		invalid_vector hyp_undef
		invalid_vector hyp_svc
		invalid_vector hyp_pabt
		invalid_vector hyp_dabt
		invalid_vector hyp_fiq

		hyp_hvc:
		/*
		* Getting here is either because of a trap from a guest,
		* or from executing HVC from the host kernel, which means
		* "do something in Hyp mode".
		*/
		push {r0, r1, r2}

		@ Check syndrome register
		mrc p15, 4, r1, c5, c2, 0 @ HSR
		lsr r0, r1, #HSR_EC_SHIFT
		cmp r0, #HSR_EC_HVC
		bne guest_trap @ Not HVC instr.

		/*
		* Let's check if the HVC came from VMID 0 and allow simple
		* switch to Hyp mode
		*/
		mrrc p15, 6, r0, r2, c2
		lsr r2, r2, #16
		and r2, r2, #0xff
		cmp r2, #0
		bne guest_trap @ Guest called HVC

		/*
		* Getting here means host called HVC, we shift parameters and branch
		* to Hyp function.
		*/
		pop {r0, r1, r2}

		/* Check for __hyp_get_vectors */
		cmp r0, #-1
		mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
		beq 1f

		push {lr}

		mov lr, r0
		mov r0, r1
		mov r1, r2
		mov r2, r3

		THUMB( orr lr, #1)
		blx lr @ Call the HYP function

		pop {lr}
		1: eret

		guest_trap:
		load_vcpu r0 @ Load VCPU pointer to r0

		#ifdef CONFIG_VFPv3
		@ Check for a VFP access
		lsr r1, r1, #HSR_EC_SHIFT
		cmp r1, #HSR_EC_CP_0_13
		beq __vfp_guest_restore
		#endif

		mov r1, #ARM_EXCEPTION_HVC
		b __guest_exit

		hyp_irq:
		push {r0, r1, r2}
		mov r1, #ARM_EXCEPTION_IRQ
		load_vcpu r0 @ Load VCPU pointer to r0
		b __guest_exit

		.ltorg

		.popsection

arch/arm/kvm/hyp/hyp.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -123,4 +123,6 @@ void __hyp_text __banked_restore_state(struct kvm_cpu_context *ctxt);

		int asmlinkage __guest_enter(struct kvm_vcpu *vcpu,
		struct kvm_cpu_context *host);
		int asmlinkage __hyp_do_panic(const char *, int, u32);

		#endif /* __ARM_KVM_HYP_H__ */