Hi,
> diff --git a/arch/arm64/include/asm/kvm_mte.h
> b/arch/arm64/include/asm/kvm_mte.h
> new file mode 100644
> index ..88dd1199670b
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_mte.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2021 ARM Ltd.
> + */
> +#ifndef __ASM_KVM_MTE_H
> +#define __ASM_KVM_MTE_H
> +
> +#ifdef __ASSEMBLY__
> +
> +#include
> +
> +#ifdef CONFIG_ARM64_MTE
> +
> +.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
> +alternative_if_not ARM64_MTE
> + b .L__skip_switch\@
> +alternative_else_nop_endif
> + mrs \reg1, hcr_el2
> + tbz \reg1, #(HCR_ATA_SHIFT), .L__skip_switch\@
> +
> + mrs_s \reg1, SYS_RGSR_EL1
> + str \reg1, [\h_ctxt, #CPU_RGSR_EL1]
> + mrs_s \reg1, SYS_GCR_EL1
> + str \reg1, [\h_ctxt, #CPU_GCR_EL1]
> +
> + ldr \reg1, [\g_ctxt, #CPU_RGSR_EL1]
> + msr_s SYS_RGSR_EL1, \reg1
> + ldr \reg1, [\g_ctxt, #CPU_GCR_EL1]
> + msr_s SYS_GCR_EL1, \reg1
> +
> +.L__skip_switch\@:
> +.endm
> +
> +.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
> +alternative_if_not ARM64_MTE
> + b .L__skip_switch\@
> +alternative_else_nop_endif
> + mrs \reg1, hcr_el2
> + tbz \reg1, #(HCR_ATA_SHIFT), .L__skip_switch\@
> +
> + mrs_s \reg1, SYS_RGSR_EL1
> + str \reg1, [\g_ctxt, #CPU_RGSR_EL1]
> + mrs_s \reg1, SYS_GCR_EL1
> + str \reg1, [\g_ctxt, #CPU_GCR_EL1]
> +
> + ldr \reg1, [\h_ctxt, #CPU_RGSR_EL1]
> + msr_s SYS_RGSR_EL1, \reg1
> + ldr \reg1, [\h_ctxt, #CPU_GCR_EL1]
> + msr_s SYS_GCR_EL1, \reg1
> +
> + isb
> +
> +.L__skip_switch\@:
> +.endm
> +
> +#else /* CONFIG_ARM64_MTE */
nit: !CONFIG_ARM64_MTE (clearer and matches the style in kvm_ptrauth.h)
Cheers,
/fuad
> +
> +.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
> +.endm
> +
> +.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
> +.endm
> +
> +#endif /* CONFIG_ARM64_MTE */
> +#endif /* __ASSEMBLY__ */
> +#endif /* __ASM_KVM_MTE_H */
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 65d15700a168..347ccac2341e 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -651,7 +651,8 @@
>
> #define INIT_SCTLR_EL2_MMU_ON \
> (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_SA | SCTLR_ELx_I | \
> -SCTLR_ELx_IESB | SCTLR_ELx_WXN | ENDIAN_SET_EL2 | SCTLR_EL2_RES1)
> +SCTLR_ELx_IESB | SCTLR_ELx_WXN | ENDIAN_SET_EL2 | \
> +SCTLR_ELx_ITFSB | SCTLR_EL2_RES1)
>
> #define INIT_SCTLR_EL2_MMU_OFF \
> (SCTLR_EL2_RES1 | ENDIAN_SET_EL2)
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index 0cb34ccb6e73..6f0044cb233e 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -111,6 +111,8 @@ int main(void)
>DEFINE(VCPU_WORKAROUND_FLAGS,offsetof(struct kvm_vcpu,
> arch.workaround_flags));
>DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
>DEFINE(CPU_USER_PT_REGS, offsetof(struct kvm_cpu_context, regs));
> + DEFINE(CPU_RGSR_EL1, offsetof(struct kvm_cpu_context,
> sys_regs[RGSR_EL1]));
> + DEFINE(CPU_GCR_EL1, offsetof(struct kvm_cpu_context,
> sys_regs[GCR_EL1]));
>DEFINE(CPU_APIAKEYLO_EL1,offsetof(struct kvm_cpu_context,
> sys_regs[APIAKEYLO_EL1]));
>DEFINE(CPU_APIBKEYLO_EL1,offsetof(struct kvm_cpu_context,
> sys_regs[APIBKEYLO_EL1]));
>DEFINE(CPU_APDAKEYLO_EL1,offsetof(struct kvm_cpu_context,
> sys_regs[APDAKEYLO_EL1]));
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> index e831d3dfd50d..435346ea1504 100644
> --- a/arch/arm64/kvm/hyp/entry.S
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -13,6 +13,7 @@
> #include
> #include
> #include
> +#include
> #include
>
> .text
> @@ -51,6 +52,9 @@ alternative_else_nop_endif
>
> add x29, x0, #VCPU_CONTEXT
>
> + // mte_switch_to_guest(g_ctxt, h_ctxt, tmp1)
> + mte_switch_to_guest x29, x1, x2
> +
> // Macro ptrauth_switch_to_guest format:
> // ptrauth_switch_to_guest(guest cxt, tmp1, tmp2, tmp3)
> // The below macro to restore guest keys is not implemented in C code
> @@ -142,6 +146,9 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
> // when this feature is enabled for kernel code.
> ptrauth_switch_to_hyp x1, x2, x3, x4, x5
>
> + // mte_switch_to_hyp(g_ctxt, h_ctxt, reg1)
> + mte_switch_to_hyp x1, x2, x3
> +
> // Restore hyp's sp_el0
> restore_sp_el0 x2, x3
>
> diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
> b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
> index cce43bfe158f..de7e14c862e6 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
> @@ -14,6 +14,7