On 09/02/16 18:44, Christoffer Dall wrote: > 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? If they did diverge, a lot of things would just break. arm64 does have different types between user and kernel, but the userspace version is guaranteed to be a strict prefix of the kernel one. I believe arm would have to enforce the same thing if it changed. > >> + 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> > Thanks, M. -- Jazz is not dead. It just smells funny... -- 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
