[PATCH v2 14/28] ARM: KVM: Add guest entry code
From: Marc Zyngier <hidden>
Date: 2016-02-04 11:00:31
Also in:
kvm, kvmarm
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
Add the very minimal piece of code that is now required to jump into the guest (and return from it). This code is only concerned with save/restoring the USR registers (r0-r12+lr for the guest, r4-r12+lr for the host), as everything else is dealt with in C (VFP is another matter though). Signed-off-by: Marc Zyngier <redacted> --- arch/arm/kvm/hyp/Makefile | 1 + arch/arm/kvm/hyp/entry.S | 70 +++++++++++++++++++++++++++++++++++++++++++++++ arch/arm/kvm/hyp/hyp.h | 2 ++ 3 files changed, 73 insertions(+) create mode 100644 arch/arm/kvm/hyp/entry.S
diff --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile
index 173bd1d..c779690 100644
--- a/arch/arm/kvm/hyp/Makefile
+++ b/arch/arm/kvm/hyp/Makefile@@ -8,3 +8,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += timer-sr.o obj-$(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
diff --git a/arch/arm/kvm/hyp/entry.S b/arch/arm/kvm/hyp/entry.S
new file mode 100644
index 0000000..32f79b0
--- /dev/null
+++ b/arch/arm/kvm/hyp/entry.S@@ -0,0 +1,70 @@ +/* + * Copyright (C) 2016 - 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/kvm_arm.h> + + .arch_extension virt + + .text + .pushsection .hyp.text, "ax" + +#define USR_REGS_OFFSET (CPU_CTXT_GP_REGS + GP_REGS_USR) + +/* int __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host) */ +ENTRY(__guest_enter) + @ Save host registers + add r1, r1, #(USR_REGS_OFFSET + S_R4) + stm r1!, {r4-r12} + str lr, [r1, #4] @ Skip SP_usr (already saved) + + @ Restore guest registers + add r0, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R0) + ldr lr, [r0, #S_LR] + ldm r0, {r0-r12} + + clrex + eret +ENDPROC(__guest_enter) + +ENTRY(__guest_exit) + /* + * return convention: + * guest r0, r1, r2 saved on the stack + * r0: vcpu pointer + * r1: exception code + */ + + add r2, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R3) + stm r2!, {r3-r12} + str lr, [r2, #4] + add r2, r0, #(VCPU_GUEST_CTXT + USR_REGS_OFFSET + S_R0) + pop {r3, r4, r5} @ r0, r1, r2 + stm r2, {r3-r5} + + ldr r0, [r0, #VCPU_HOST_CTXT] + add r0, r0, #(USR_REGS_OFFSET + S_R4) + ldm r0!, {r4-r12} + ldr lr, [r0, #4] + + mov r0, r1 + bx lr +ENDPROC(__guest_exit) + + .popsection +
diff --git a/arch/arm/kvm/hyp/hyp.h b/arch/arm/kvm/hyp/hyp.h
index 278eb1f..b3f6ed2 100644
--- a/arch/arm/kvm/hyp/hyp.h
+++ b/arch/arm/kvm/hyp/hyp.h@@ -110,4 +110,6 @@ static inline bool __vfp_enabled(void) void __hyp_text __banked_save_state(struct kvm_cpu_context *ctxt); void __hyp_text __banked_restore_state(struct kvm_cpu_context *ctxt); +int asmlinkage __guest_enter(struct kvm_vcpu *vcpu, + struct kvm_cpu_context *host); #endif /* __ARM_KVM_HYP_H__ */
--
2.1.4