Subject: [RFC 07/55] KVM: arm/arm64: Add virtual EL2 state emulation framework

From: [email-masked] (Christoffer Dall)
Date: Wed, 22 Feb 2017 12:12:11 +0100

On Mon, Jan 09, 2017 at 01:24:03AM -0500, Jintack Lim wrote:
> From: Christoffer Dall <[email-masked]>
> 
> Add a framework to set up the guest's context depending on the guest's
> exception level. A chosen context is written to hardware in the lowvisor.
> We don't set the virtual EL2 context yet.

We need to improve this commit message.

I think this commit is just trying to prepare to be able to switch
between the normal EL1 sysreg state or using the shadow sysreg to
emulate virtual EL2, but without any functional change so far.

Is that correct?

> 
> Signed-off-by: Christoffer Dall <[email-masked]>
> Signed-off-by: Jintack Lim <[email-masked]>
> ---
>  arch/arm/include/asm/kvm_emulate.h   |   4 ++
>  arch/arm/kvm/arm.c                   |   5 ++
>  arch/arm64/include/asm/kvm_emulate.h |   4 ++
>  arch/arm64/kvm/Makefile              |   2 +-
>  arch/arm64/kvm/context.c             |  49 ++++++++++++++++
>  arch/arm64/kvm/hyp/sysreg-sr.c       | 109 +++++++++++++++++++----------------
>  6 files changed, 122 insertions(+), 51 deletions(-)
>  create mode 100644 arch/arm64/kvm/context.c
> 
> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
> index 399cd75e..0a03b7d 100644
> --- a/arch/arm/include/asm/kvm_emulate.h
> +++ b/arch/arm/include/asm/kvm_emulate.h
> @@ -47,6 +47,10 @@ static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, u8 reg_num,
>  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  
> +static inline void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu) { };
> +static inline void kvm_arm_restore_shadow_state(struct kvm_vcpu *vcpu) { };
> +static inline void kvm_arm_init_cpu_context(kvm_cpu_context_t *cpu_ctxt) { };
> +
>  static inline bool kvm_condition_valid(const struct kvm_vcpu *vcpu)
>  {
>  	return kvm_condition_valid32(vcpu);
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index d2dfa32..436bf5a 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -41,6 +41,7 @@
>  #include <asm/virt.h>
>  #include <asm/kvm_arm.h>
>  #include <asm/kvm_asm.h>
> +#include <asm/kvm_hyp.h>
>  #include <asm/kvm_mmu.h>
>  #include <asm/kvm_emulate.h>
>  #include <asm/kvm_coproc.h>
> @@ -646,6 +647,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  		}
>  
>  		kvm_arm_setup_debug(vcpu);
> +		kvm_arm_setup_shadow_state(vcpu);
>  
>  		/**************************************************************
>  		 * Enter the guest
> @@ -662,6 +664,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  		 * Back from guest
>  		 *************************************************************/
>  
> +		kvm_arm_restore_shadow_state(vcpu);
>  		kvm_arm_clear_debug(vcpu);
>  
>  		/*
> @@ -1369,6 +1372,8 @@ static int init_hyp_mode(void)
>  			kvm_err("Cannot map host CPU state: %d\n", err);
>  			goto out_err;
>  		}
> +
> +		kvm_arm_init_cpu_context(cpu_ctxt);
>  	}
>  
>  	kvm_info("Hyp mode initialized successfully\n");
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 830be2e..8892c82 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -42,6 +42,10 @@
>  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  
> +void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu);
> +void kvm_arm_restore_shadow_state(struct kvm_vcpu *vcpu);
> +void kvm_arm_init_cpu_context(kvm_cpu_context_t *cpu_ctxt);
> +
>  static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
>  {
>  	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
> index d50a82a..7811d27 100644
> --- a/arch/arm64/kvm/Makefile
> +++ b/arch/arm64/kvm/Makefile
> @@ -16,7 +16,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/e
>  kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/arm.o $(ARM)/mmu.o $(ARM)/mmio.o
>  kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o
>  
> -kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o
> +kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o context.o
>  kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
>  kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o
>  kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/aarch32.o
> diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c
> new file mode 100644
> index 0000000..320afc6
> --- /dev/null
> +++ b/arch/arm64/kvm/context.c
> @@ -0,0 +1,49 @@
> +/*
> + * Copyright (C) 2016 - Linaro Ltd.
> + * Author: Christoffer Dall <[email-masked]>
> + *
> + * 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/kvm_host.h>
> +#include <asm/kvm_emulate.h>
> +
> +/**
> + * kvm_arm_setup_shadow_state -- prepare shadow state based on emulated mode
> + * @vcpu: The VCPU pointer
> + */
> +void kvm_arm_setup_shadow_state(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
> +
> +	ctxt->hw_pstate = *vcpu_cpsr(vcpu);
> +	ctxt->hw_sys_regs = ctxt->sys_regs;
> +	ctxt->hw_sp_el1 = ctxt->gp_regs.sp_el1;
> +}
> +
> +/**
> + * kvm_arm_restore_shadow_state -- write back shadow state from guest
> + * @vcpu: The VCPU pointer
> + */
> +void kvm_arm_restore_shadow_state(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
> +
> +	*vcpu_cpsr(vcpu) = ctxt->hw_pstate;
> +	ctxt->gp_regs.sp_el1 = ctxt->hw_sp_el1;
> +}
> +
> +void kvm_arm_init_cpu_context(kvm_cpu_context_t *cpu_ctxt)
> +{
> +	cpu_ctxt->hw_sys_regs = &cpu_ctxt->sys_regs[0];
> +}
> diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
> index 9341376..f2a1b32 100644
> --- a/arch/arm64/kvm/hyp/sysreg-sr.c
> +++ b/arch/arm64/kvm/hyp/sysreg-sr.c
> @@ -19,6 +19,7 @@
>  #include <linux/kvm_host.h>
>  
>  #include <asm/kvm_asm.h>
> +#include <asm/kvm_emulate.h>
>  #include <asm/kvm_hyp.h>
>  
>  /* Yes, this does nothing, on purpose */
> @@ -33,37 +34,41 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
>  
>  static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
>  {
> -	ctxt->sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
> -	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
> -	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
> -	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
> -	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
> +	u64 *sys_regs = kern_hyp_va(ctxt->hw_sys_regs);
> +
> +	sys_regs[ACTLR_EL1]	= read_sysreg(actlr_el1);
> +	sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
> +	sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
> +	sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);
> +	sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
>  	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);
>  	ctxt->gp_regs.regs.pc		= read_sysreg_el2(elr);
> -	ctxt->gp_regs.regs.pstate	= read_sysreg_el2(spsr);
> +	ctxt->hw_pstate			= read_sysreg_el2(spsr);
>  }
>  
>  static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
>  {
> -	ctxt->sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
> -	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
> -	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg_el1(sctlr);
> -	ctxt->sys_regs[CPACR_EL1]	= read_sysreg_el1(cpacr);
> -	ctxt->sys_regs[TTBR0_EL1]	= read_sysreg_el1(ttbr0);
> -	ctxt->sys_regs[TTBR1_EL1]	= read_sysreg_el1(ttbr1);
> -	ctxt->sys_regs[TCR_EL1]		= read_sysreg_el1(tcr);
> -	ctxt->sys_regs[ESR_EL1]		= read_sysreg_el1(esr);
> -	ctxt->sys_regs[AFSR0_EL1]	= read_sysreg_el1(afsr0);
> -	ctxt->sys_regs[AFSR1_EL1]	= read_sysreg_el1(afsr1);
> -	ctxt->sys_regs[FAR_EL1]		= read_sysreg_el1(far);
> -	ctxt->sys_regs[MAIR_EL1]	= read_sysreg_el1(mair);
> -	ctxt->sys_regs[VBAR_EL1]	= read_sysreg_el1(vbar);
> -	ctxt->sys_regs[CONTEXTIDR_EL1]	= read_sysreg_el1(contextidr);
> -	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg_el1(amair);
> -	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg_el1(cntkctl);
> -	ctxt->sys_regs[PAR_EL1]		= read_sysreg(par_el1);
> -
> -	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);
> +	u64 *sys_regs = kern_hyp_va(ctxt->hw_sys_regs);
> +
> +	sys_regs[MPIDR_EL1]	= read_sysreg(vmpidr_el2);
> +	sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
> +	sys_regs[SCTLR_EL1]	= read_sysreg_el1(sctlr);
> +	sys_regs[CPACR_EL1]	= read_sysreg_el1(cpacr);
> +	sys_regs[TTBR0_EL1]	= read_sysreg_el1(ttbr0);
> +	sys_regs[TTBR1_EL1]	= read_sysreg_el1(ttbr1);
> +	sys_regs[TCR_EL1]	= read_sysreg_el1(tcr);
> +	sys_regs[ESR_EL1]	= read_sysreg_el1(esr);
> +	sys_regs[AFSR0_EL1]	= read_sysreg_el1(afsr0);
> +	sys_regs[AFSR1_EL1]	= read_sysreg_el1(afsr1);
> +	sys_regs[FAR_EL1]	= read_sysreg_el1(far);
> +	sys_regs[MAIR_EL1]	= read_sysreg_el1(mair);
> +	sys_regs[VBAR_EL1]	= read_sysreg_el1(vbar);
> +	sys_regs[CONTEXTIDR_EL1]	= read_sysreg_el1(contextidr);
> +	sys_regs[AMAIR_EL1]	= read_sysreg_el1(amair);
> +	sys_regs[CNTKCTL_EL1]	= read_sysreg_el1(cntkctl);
> +	sys_regs[PAR_EL1]		= read_sysreg(par_el1);
> +
> +	ctxt->hw_sp_el1			= read_sysreg(sp_el1);
>  	ctxt->gp_regs.elr_el1		= read_sysreg_el1(elr);
>  	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
>  }
> @@ -86,37 +91,41 @@ void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
>  
>  static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
>  {
> -	write_sysreg(ctxt->sys_regs[ACTLR_EL1],	  actlr_el1);
> -	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);
> -	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
> -	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);
> -	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
> +	u64 *sys_regs = kern_hyp_va(ctxt->hw_sys_regs);
> +
> +	write_sysreg(sys_regs[ACTLR_EL1],	  actlr_el1);
> +	write_sysreg(sys_regs[TPIDR_EL0],	  tpidr_el0);
> +	write_sysreg(sys_regs[TPIDRRO_EL0],	tpidrro_el0);
> +	write_sysreg(sys_regs[TPIDR_EL1],	  tpidr_el1);
> +	write_sysreg(sys_regs[MDSCR_EL1],	  mdscr_el1);
>  	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);
>  	write_sysreg_el2(ctxt->gp_regs.regs.pc,	  elr);
> -	write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
> +	write_sysreg_el2(ctxt->hw_pstate,	  spsr);
>  }
>  
>  static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
>  {
> -	write_sysreg(ctxt->sys_regs[MPIDR_EL1],		vmpidr_el2);
> -	write_sysreg(ctxt->sys_regs[CSSELR_EL1],	csselr_el1);
> -	write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1],	sctlr);
> -	write_sysreg_el1(ctxt->sys_regs[CPACR_EL1],	cpacr);
> -	write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1],	ttbr0);
> -	write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1],	ttbr1);
> -	write_sysreg_el1(ctxt->sys_regs[TCR_EL1],	tcr);
> -	write_sysreg_el1(ctxt->sys_regs[ESR_EL1],	esr);
> -	write_sysreg_el1(ctxt->sys_regs[AFSR0_EL1],	afsr0);
> -	write_sysreg_el1(ctxt->sys_regs[AFSR1_EL1],	afsr1);
> -	write_sysreg_el1(ctxt->sys_regs[FAR_EL1],	far);
> -	write_sysreg_el1(ctxt->sys_regs[MAIR_EL1],	mair);
> -	write_sysreg_el1(ctxt->sys_regs[VBAR_EL1],	vbar);
> -	write_sysreg_el1(ctxt->sys_regs[CONTEXTIDR_EL1],contextidr);
> -	write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1],	amair);
> -	write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], 	cntkctl);
> -	write_sysreg(ctxt->sys_regs[PAR_EL1],		par_el1);
> -
> -	write_sysreg(ctxt->gp_regs.sp_el1,		sp_el1);
> +	u64 *sys_regs = kern_hyp_va(ctxt->hw_sys_regs);
> +
> +	write_sysreg(sys_regs[MPIDR_EL1],	vmpidr_el2);
> +	write_sysreg(sys_regs[CSSELR_EL1],	csselr_el1);
> +	write_sysreg_el1(sys_regs[SCTLR_EL1],	sctlr);
> +	write_sysreg_el1(sys_regs[CPACR_EL1],	cpacr);
> +	write_sysreg_el1(sys_regs[TTBR0_EL1],	ttbr0);
> +	write_sysreg_el1(sys_regs[TTBR1_EL1],	ttbr1);
> +	write_sysreg_el1(sys_regs[TCR_EL1],	tcr);
> +	write_sysreg_el1(sys_regs[ESR_EL1],	esr);
> +	write_sysreg_el1(sys_regs[AFSR0_EL1],	afsr0);
> +	write_sysreg_el1(sys_regs[AFSR1_EL1],	afsr1);
> +	write_sysreg_el1(sys_regs[FAR_EL1],	far);
> +	write_sysreg_el1(sys_regs[MAIR_EL1],	mair);
> +	write_sysreg_el1(sys_regs[VBAR_EL1],	vbar);
> +	write_sysreg_el1(sys_regs[CONTEXTIDR_EL1], contextidr);
> +	write_sysreg_el1(sys_regs[AMAIR_EL1],	amair);
> +	write_sysreg_el1(sys_regs[CNTKCTL_EL1], cntkctl);
> +	write_sysreg(sys_regs[PAR_EL1],		par_el1);
> +
> +	write_sysreg(ctxt->hw_sp_el1,			sp_el1);
>  	write_sysreg_el1(ctxt->gp_regs.elr_el1,		elr);
>  	write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
>  }
> -- 
> 1.9.1
> 
>