On Thu, Feb 04, 2016 at 11:00:31AM +0000, Marc Zyngier wrote: > 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 <marc.zyngier@xxxxxxx> > --- > 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@xxxxxxx> > + * > + * 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) this really relies on offsetof(struct pt_regs, ARM_r0) == 0, which I guess will likely never change, but given there's both a kernel and uapi version of struct pt_regs, are we sure about this? > + 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 > Otherwise: Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
