Re: [PATCH v17 3/6] KVM: arm64: Save/restore MTE registers

2021-06-22 Thread Fuad Tabba
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

[PATCH v17 3/6] KVM: arm64: Save/restore MTE registers

2021-06-21 Thread Steven Price
Define the new system registers that MTE introduces and context switch
them. The MTE feature is still hidden from the ID register as it isn't
supported in a VM yet.

Reviewed-by: Catalin Marinas 
Signed-off-by: Steven Price 
---
 arch/arm64/include/asm/kvm_arm.h   |  3 +-
 arch/arm64/include/asm/kvm_host.h  |  6 ++
 arch/arm64/include/asm/kvm_mte.h   | 66 ++
 arch/arm64/include/asm/sysreg.h|  3 +-
 arch/arm64/kernel/asm-offsets.c|  2 +
 arch/arm64/kvm/hyp/entry.S |  7 +++
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 21 +++
 arch/arm64/kvm/sys_regs.c  | 22 ++--
 8 files changed, 124 insertions(+), 6 deletions(-)
 create mode 100644 arch/arm64/include/asm/kvm_mte.h

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 692c9049befa..d436831dd706 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -12,7 +12,8 @@
 #include 
 
 /* Hyp Configuration Register (HCR) bits */
-#define HCR_ATA(UL(1) << 56)
+#define HCR_ATA_SHIFT  56
+#define HCR_ATA(UL(1) << HCR_ATA_SHIFT)
 #define HCR_FWB(UL(1) << 46)
 #define HCR_API(UL(1) << 41)
 #define HCR_APK(UL(1) << 40)
diff --git a/arch/arm64/include/asm/kvm_host.h 
b/arch/arm64/include/asm/kvm_host.h
index afaa5333f0e4..309e36cc1b42 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -208,6 +208,12 @@ enum vcpu_sysreg {
CNTP_CVAL_EL0,
CNTP_CTL_EL0,
 
+   /* Memory Tagging Extension registers */
+   RGSR_EL1,   /* Random Allocation Tag Seed Register */
+   GCR_EL1,/* Tag Control Register */
+   TFSR_EL1,   /* Tag Fault Status Register (EL1) */
+   TFSRE0_EL1, /* Tag Fault Status Register (EL0) */
+
/* 32bit specific registers. Keep them at the end of the range */
DACR32_EL2, /* Domain Access Control Register */
IFSR32_EL2, /* Instruction Fault Status Register */
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 */
+
+.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