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Commit b97b66c1 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

arm64: KVM: Implement guest entry 



Contrary to the previous patch, the guest entry is fairly different
from its assembly counterpart, mostly because it is only concerned
with saving/restoring the GP registers, and nothing else.

Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 8eb99267

arch/arm64/kvm/hyp/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -7,3 +7,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o 
obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o

obj-$(CONFIG_KVM_ARM_HOST) += entry.o

arch/arm64/kvm/hyp/entry.S

0 → 100644
+130 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2015 - ARM Ltd

 * Author: Marc Zyngier <marc.zyngier@arm.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, see <http://www.gnu.org/licenses/>.

 */



#include <linux/linkage.h>



#include <asm/asm-offsets.h>

#include <asm/assembler.h>

#include <asm/fpsimdmacros.h>

#include <asm/kvm.h>

#include <asm/kvm_arm.h>

#include <asm/kvm_asm.h>

#include <asm/kvm_mmu.h>



#define CPU_GP_REG_OFFSET(x)	(CPU_GP_REGS + x)

#define CPU_XREG_OFFSET(x)	CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)



	.text

	.pushsection	.hyp.text, "ax"



.macro save_callee_saved_regs ctxt

	stp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]

	stp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]

	stp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]

	stp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]

	stp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]

	stp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]

.endm



.macro restore_callee_saved_regs ctxt

	ldp	x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)]

	ldp	x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)]

	ldp	x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)]

	ldp	x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)]

	ldp	x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)]

	ldp	x29, lr,  [\ctxt, #CPU_XREG_OFFSET(29)]

.endm



/*

 * u64 __guest_enter(struct kvm_vcpu *vcpu,

 *		     struct kvm_cpu_context *host_ctxt);

 */

ENTRY(__guest_enter)

	// x0: vcpu

	// x1: host/guest context

	// x2-x18: clobbered by macros



	// Store the host regs

	save_callee_saved_regs x1



	// Preserve vcpu & host_ctxt for use at exit time

	stp	x0, x1, [sp, #-16]!



	add	x1, x0, #VCPU_CONTEXT



	// Prepare x0-x1 for later restore by pushing them onto the stack

	ldp	x2, x3, [x1, #CPU_XREG_OFFSET(0)]

	stp	x2, x3, [sp, #-16]!



	// x2-x18

	ldp	x2, x3,   [x1, #CPU_XREG_OFFSET(2)]

	ldp	x4, x5,   [x1, #CPU_XREG_OFFSET(4)]

	ldp	x6, x7,   [x1, #CPU_XREG_OFFSET(6)]

	ldp	x8, x9,   [x1, #CPU_XREG_OFFSET(8)]

	ldp	x10, x11, [x1, #CPU_XREG_OFFSET(10)]

	ldp	x12, x13, [x1, #CPU_XREG_OFFSET(12)]

	ldp	x14, x15, [x1, #CPU_XREG_OFFSET(14)]

	ldp	x16, x17, [x1, #CPU_XREG_OFFSET(16)]

	ldr	x18,      [x1, #CPU_XREG_OFFSET(18)]



	// x19-x29, lr

	restore_callee_saved_regs x1



	// Last bits of the 64bit state

	ldp	x0, x1, [sp], #16



	// Do not touch any register after this!

	eret

ENDPROC(__guest_enter)



ENTRY(__guest_exit)

	// x0: vcpu

	// x1: return code

	// x2-x3: free

	// x4-x29,lr: vcpu regs

	// vcpu x0-x3 on the stack



	add	x2, x0, #VCPU_CONTEXT



	stp	x4, x5,   [x2, #CPU_XREG_OFFSET(4)]

	stp	x6, x7,   [x2, #CPU_XREG_OFFSET(6)]

	stp	x8, x9,   [x2, #CPU_XREG_OFFSET(8)]

	stp	x10, x11, [x2, #CPU_XREG_OFFSET(10)]

	stp	x12, x13, [x2, #CPU_XREG_OFFSET(12)]

	stp	x14, x15, [x2, #CPU_XREG_OFFSET(14)]

	stp	x16, x17, [x2, #CPU_XREG_OFFSET(16)]

	str	x18,      [x2, #CPU_XREG_OFFSET(18)]



	ldp	x6, x7, [sp], #16	// x2, x3

	ldp	x4, x5, [sp], #16	// x0, x1



	stp	x4, x5, [x2, #CPU_XREG_OFFSET(0)]

	stp	x6, x7, [x2, #CPU_XREG_OFFSET(2)]



	save_callee_saved_regs x2



	// Restore vcpu & host_ctxt from the stack

	// (preserving return code in x1)

	ldp	x0, x2, [sp], #16

	// Now restore the host regs

	restore_callee_saved_regs x2



	mov	x0, x1

	ret

ENDPROC(__guest_exit)



	/* Insert fault handling here */

arch/arm64/kvm/hyp/hyp.h

+2 −0
Original line number Diff line number Diff line
@@ -52,5 +52,7 @@ void __debug_restore_state(struct kvm_vcpu *vcpu, 
void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);

void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);



u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);



#endif /* __ARM64_KVM_HYP_H__ */