subject:"\[PATCH v2 12\/21\] arm64\: KVM\: Implement fpsimd save\/restore"

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

2015-12-02 Thread Marc Zyngier

On 02/12/15 11:53, Christoffer Dall wrote:
> On Fri, Nov 27, 2015 at 06:50:06PM +, Marc Zyngier wrote:
>> Implement the fpsimd save restore, keeping the lazy part in
>> assembler (as returning to C would be overkill).
>>
>> Signed-off-by: Marc Zyngier 
>> ---
>>  arch/arm64/kvm/hyp/Makefile|  1 +
>>  arch/arm64/kvm/hyp/entry.S | 32 +++-
>>  arch/arm64/kvm/hyp/fpsimd.S| 33 +
>>  arch/arm64/kvm/hyp/hyp.h   |  7 +++
>>  arch/arm64/kvm/hyp/switch.c|  8 
>>  arch/arm64/kvm/hyp/sysreg-sr.c |  2 +-
>>  6 files changed, 81 insertions(+), 2 deletions(-)
>>  create mode 100644 arch/arm64/kvm/hyp/fpsimd.S
>>
>> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
>> index 9c11b0f..56238d0 100644
>> --- a/arch/arm64/kvm/hyp/Makefile
>> +++ b/arch/arm64/kvm/hyp/Makefile
>> @@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
>>  obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
>>  obj-$(CONFIG_KVM_ARM_HOST) += entry.o
>>  obj-$(CONFIG_KVM_ARM_HOST) += switch.o
>> +obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
>> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
>> index 2c4449a..7552922 100644
>> --- a/arch/arm64/kvm/hyp/entry.S
>> +++ b/arch/arm64/kvm/hyp/entry.S
>> @@ -27,6 +27,7 @@
>>  
>>  #define CPU_GP_REG_OFFSET(x)(CPU_GP_REGS + x)
>>  #define CPU_XREG_OFFSET(x)  CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
>> +#define CPU_SYSREG_OFFSET(x)(CPU_SYSREGS + 8*x)
>>  
>>  .text
>>  .pushsection.hyp.text, "ax"
>> @@ -152,4 +153,33 @@ ENTRY(__guest_exit)
>>  ret
>>  ENDPROC(__guest_exit)
>>  
>> -/* Insert fault handling here */
>> +ENTRY(__fpsimd_guest_restore)
>> +pushx4, lr
>> +
>> +mrs x2, cptr_el2
>> +bic x2, x2, #CPTR_EL2_TFP
>> +msr cptr_el2, x2
>> +isb
>> +
>> +mrs x3, tpidr_el2
>> +
>> +ldr x0, [x3, #VCPU_HOST_CONTEXT]
>> +kern_hyp_va x0
>> +add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
>> +bl  __fpsimd_save_state
>> +
>> +add x2, x3, #VCPU_CONTEXT
>> +add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
>> +bl  __fpsimd_restore_state
>> +
>> +mrs x1, hcr_el2
>> +tbnzx1, #HCR_RW_SHIFT, 1f
> 
> nit: Add a comment along the lines of:
> // Skip restoring fpexc32 for AArch64 guests
> 
>> +ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]
>> +msr fpexc32_el2, x4
>> +1:
>> +pop x4, lr
>> +pop x2, x3
>> +pop x0, x1
>> +
>> +eret
>> +ENDPROC(__fpsimd_guest_restore)
>> diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
>> new file mode 100644
>> index 000..da3f22c
>> --- /dev/null
>> +++ b/arch/arm64/kvm/hyp/fpsimd.S
>> @@ -0,0 +1,33 @@
>> +/*
>> + * Copyright (C) 2015 - ARM Ltd
>> + * Author: Marc Zyngier 
>> + *
>> + * 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 .
>> + */
>> +
>> +#include 
>> +
>> +#include 
>> +
>> +.text
>> +.pushsection.hyp.text, "ax"
>> +
>> +ENTRY(__fpsimd_save_state)
>> +fpsimd_save x0, 1
>> +ret
>> +ENDPROC(__fpsimd_save_state)
>> +
>> +ENTRY(__fpsimd_restore_state)
>> +fpsimd_restore  x0, 1
>> +ret
>> +ENDPROC(__fpsimd_restore_state)
>> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
>> index f0427ee..18365dd 100644
>> --- a/arch/arm64/kvm/hyp/hyp.h
>> +++ b/arch/arm64/kvm/hyp/hyp.h
>> @@ -66,6 +66,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu,
>>  void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);
>>  void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
>>  
>> +void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
>> +void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
>> +static inline bool __fpsimd_enabled(void)
>> +{
>> +return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
>> +}
>> +
>>  u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
>>  
>>  #endif /* __ARM64_KVM_HYP_H__ */
>> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
>> index d67ed9e..8affc19 100644
>> --- a/arch/arm64/kvm/hyp/switch.c
>> +++ b/arch/arm64/kvm/hyp/switch.c
>> @@ -88,6 +88,7 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
>>  {
>>  struct kvm_cpu_context *host_ctxt;
>>  struct kvm_cpu_context *guest_ctxt;
>> +bool fp_enabled;
>>

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

2015-12-02 Thread Christoffer Dall

On Wed, Dec 02, 2015 at 03:29:50PM +, Marc Zyngier wrote:
> On 02/12/15 11:53, Christoffer Dall wrote:
> > On Fri, Nov 27, 2015 at 06:50:06PM +, Marc Zyngier wrote:
> >> Implement the fpsimd save restore, keeping the lazy part in
> >> assembler (as returning to C would be overkill).
> >>
> >> Signed-off-by: Marc Zyngier 
> >> ---
> >>  arch/arm64/kvm/hyp/Makefile|  1 +
> >>  arch/arm64/kvm/hyp/entry.S | 32 +++-
> >>  arch/arm64/kvm/hyp/fpsimd.S| 33 +
> >>  arch/arm64/kvm/hyp/hyp.h   |  7 +++
> >>  arch/arm64/kvm/hyp/switch.c|  8 
> >>  arch/arm64/kvm/hyp/sysreg-sr.c |  2 +-
> >>  6 files changed, 81 insertions(+), 2 deletions(-)
> >>  create mode 100644 arch/arm64/kvm/hyp/fpsimd.S
> >>
> >> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> >> index 9c11b0f..56238d0 100644
> >> --- a/arch/arm64/kvm/hyp/Makefile
> >> +++ b/arch/arm64/kvm/hyp/Makefile
> >> @@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
> >>  obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
> >>  obj-$(CONFIG_KVM_ARM_HOST) += entry.o
> >>  obj-$(CONFIG_KVM_ARM_HOST) += switch.o
> >> +obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
> >> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> >> index 2c4449a..7552922 100644
> >> --- a/arch/arm64/kvm/hyp/entry.S
> >> +++ b/arch/arm64/kvm/hyp/entry.S
> >> @@ -27,6 +27,7 @@
> >>  
> >>  #define CPU_GP_REG_OFFSET(x)  (CPU_GP_REGS + x)
> >>  #define CPU_XREG_OFFSET(x)CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 
> >> 8*x)
> >> +#define CPU_SYSREG_OFFSET(x)  (CPU_SYSREGS + 8*x)
> >>  
> >>.text
> >>.pushsection.hyp.text, "ax"
> >> @@ -152,4 +153,33 @@ ENTRY(__guest_exit)
> >>ret
> >>  ENDPROC(__guest_exit)
> >>  
> >> -  /* Insert fault handling here */
> >> +ENTRY(__fpsimd_guest_restore)
> >> +  pushx4, lr
> >> +
> >> +  mrs x2, cptr_el2
> >> +  bic x2, x2, #CPTR_EL2_TFP
> >> +  msr cptr_el2, x2
> >> +  isb
> >> +
> >> +  mrs x3, tpidr_el2
> >> +
> >> +  ldr x0, [x3, #VCPU_HOST_CONTEXT]
> >> +  kern_hyp_va x0
> >> +  add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> +  bl  __fpsimd_save_state
> >> +
> >> +  add x2, x3, #VCPU_CONTEXT
> >> +  add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> +  bl  __fpsimd_restore_state
> >> +
> >> +  mrs x1, hcr_el2
> >> +  tbnzx1, #HCR_RW_SHIFT, 1f
> > 
> > nit: Add a comment along the lines of:
> > // Skip restoring fpexc32 for AArch64 guests
> > 
> >> +  ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]
> >> +  msr fpexc32_el2, x4
> >> +1:
> >> +  pop x4, lr
> >> +  pop x2, x3
> >> +  pop x0, x1
> >> +
> >> +  eret
> >> +ENDPROC(__fpsimd_guest_restore)
> >> diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
> >> new file mode 100644
> >> index 000..da3f22c
> >> --- /dev/null
> >> +++ b/arch/arm64/kvm/hyp/fpsimd.S
> >> @@ -0,0 +1,33 @@
> >> +/*
> >> + * Copyright (C) 2015 - ARM Ltd
> >> + * Author: Marc Zyngier 
> >> + *
> >> + * 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 .
> >> + */
> >> +
> >> +#include 
> >> +
> >> +#include 
> >> +
> >> +  .text
> >> +  .pushsection.hyp.text, "ax"
> >> +
> >> +ENTRY(__fpsimd_save_state)
> >> +  fpsimd_save x0, 1
> >> +  ret
> >> +ENDPROC(__fpsimd_save_state)
> >> +
> >> +ENTRY(__fpsimd_restore_state)
> >> +  fpsimd_restore  x0, 1
> >> +  ret
> >> +ENDPROC(__fpsimd_restore_state)
> >> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
> >> index f0427ee..18365dd 100644
> >> --- a/arch/arm64/kvm/hyp/hyp.h
> >> +++ b/arch/arm64/kvm/hyp/hyp.h
> >> @@ -66,6 +66,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu,
> >>  void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);
> >>  void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
> >>  
> >> +void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
> >> +void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
> >> +static inline bool __fpsimd_enabled(void)
> >> +{
> >> +  return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
> >> +}
> >> +
> >>  u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context 
> >> *host_ctxt);
> >>  
> >>  #endif /* __ARM64_KVM_HYP_H__ */
> >> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> >> index

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

2015-12-02 Thread Christoffer Dall

On Fri, Nov 27, 2015 at 06:50:06PM +, Marc Zyngier wrote:
> Implement the fpsimd save restore, keeping the lazy part in
> assembler (as returning to C would be overkill).
> 
> Signed-off-by: Marc Zyngier 
> ---
>  arch/arm64/kvm/hyp/Makefile|  1 +
>  arch/arm64/kvm/hyp/entry.S | 32 +++-
>  arch/arm64/kvm/hyp/fpsimd.S| 33 +
>  arch/arm64/kvm/hyp/hyp.h   |  7 +++
>  arch/arm64/kvm/hyp/switch.c|  8 
>  arch/arm64/kvm/hyp/sysreg-sr.c |  2 +-
>  6 files changed, 81 insertions(+), 2 deletions(-)
>  create mode 100644 arch/arm64/kvm/hyp/fpsimd.S
> 
> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> index 9c11b0f..56238d0 100644
> --- a/arch/arm64/kvm/hyp/Makefile
> +++ b/arch/arm64/kvm/hyp/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += entry.o
>  obj-$(CONFIG_KVM_ARM_HOST) += switch.o
> +obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
> diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
> index 2c4449a..7552922 100644
> --- a/arch/arm64/kvm/hyp/entry.S
> +++ b/arch/arm64/kvm/hyp/entry.S
> @@ -27,6 +27,7 @@
>  
>  #define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x)
>  #define CPU_XREG_OFFSET(x)   CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
> +#define CPU_SYSREG_OFFSET(x) (CPU_SYSREGS + 8*x)
>  
>   .text
>   .pushsection.hyp.text, "ax"
> @@ -152,4 +153,33 @@ ENTRY(__guest_exit)
>   ret
>  ENDPROC(__guest_exit)
>  
> - /* Insert fault handling here */
> +ENTRY(__fpsimd_guest_restore)
> + pushx4, lr
> +
> + mrs x2, cptr_el2
> + bic x2, x2, #CPTR_EL2_TFP
> + msr cptr_el2, x2
> + isb
> +
> + mrs x3, tpidr_el2
> +
> + ldr x0, [x3, #VCPU_HOST_CONTEXT]
> + kern_hyp_va x0
> + add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> + bl  __fpsimd_save_state
> +
> + add x2, x3, #VCPU_CONTEXT
> + add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> + bl  __fpsimd_restore_state
> +
> + mrs x1, hcr_el2
> + tbnzx1, #HCR_RW_SHIFT, 1f

nit: Add a comment along the lines of:
// Skip restoring fpexc32 for AArch64 guests

> + ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]
> + msr fpexc32_el2, x4
> +1:
> + pop x4, lr
> + pop x2, x3
> + pop x0, x1
> +
> + eret
> +ENDPROC(__fpsimd_guest_restore)
> diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
> new file mode 100644
> index 000..da3f22c
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/fpsimd.S
> @@ -0,0 +1,33 @@
> +/*
> + * Copyright (C) 2015 - ARM Ltd
> + * Author: Marc Zyngier 
> + *
> + * 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 .
> + */
> +
> +#include 
> +
> +#include 
> +
> + .text
> + .pushsection.hyp.text, "ax"
> +
> +ENTRY(__fpsimd_save_state)
> + fpsimd_save x0, 1
> + ret
> +ENDPROC(__fpsimd_save_state)
> +
> +ENTRY(__fpsimd_restore_state)
> + fpsimd_restore  x0, 1
> + ret
> +ENDPROC(__fpsimd_restore_state)
> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
> index f0427ee..18365dd 100644
> --- a/arch/arm64/kvm/hyp/hyp.h
> +++ b/arch/arm64/kvm/hyp/hyp.h
> @@ -66,6 +66,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu,
>  void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);
>  void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
>  
> +void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
> +void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
> +static inline bool __fpsimd_enabled(void)
> +{
> + return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
> +}
> +
>  u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
>  
>  #endif /* __ARM64_KVM_HYP_H__ */
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index d67ed9e..8affc19 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -88,6 +88,7 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
>  {
>   struct kvm_cpu_context *host_ctxt;
>   struct kvm_cpu_context *guest_ctxt;
> + bool fp_enabled;
>   u64 exit_code;
>  
>   vcpu = kern_hyp_va(vcpu);
> @@ -117,6 +118,8 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
>   exit_code = __guest_enter(vcpu,

[PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

2015-11-27 Thread Marc Zyngier

Implement the fpsimd save restore, keeping the lazy part in
assembler (as returning to C would be overkill).

Signed-off-by: Marc Zyngier 
---
 arch/arm64/kvm/hyp/Makefile|  1 +
 arch/arm64/kvm/hyp/entry.S | 32 +++-
 arch/arm64/kvm/hyp/fpsimd.S| 33 +
 arch/arm64/kvm/hyp/hyp.h   |  7 +++
 arch/arm64/kvm/hyp/switch.c|  8 
 arch/arm64/kvm/hyp/sysreg-sr.c |  2 +-
 6 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm64/kvm/hyp/fpsimd.S

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 9c11b0f..56238d0 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
 obj-$(CONFIG_KVM_ARM_HOST) += entry.o
 obj-$(CONFIG_KVM_ARM_HOST) += switch.o
+obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 2c4449a..7552922 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -27,6 +27,7 @@
 
 #define CPU_GP_REG_OFFSET(x)   (CPU_GP_REGS + x)
 #define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
+#define CPU_SYSREG_OFFSET(x)   (CPU_SYSREGS + 8*x)
 
.text
.pushsection.hyp.text, "ax"
@@ -152,4 +153,33 @@ ENTRY(__guest_exit)
ret
 ENDPROC(__guest_exit)
 
-   /* Insert fault handling here */
+ENTRY(__fpsimd_guest_restore)
+   pushx4, lr
+
+   mrs x2, cptr_el2
+   bic x2, x2, #CPTR_EL2_TFP
+   msr cptr_el2, x2
+   isb
+
+   mrs x3, tpidr_el2
+
+   ldr x0, [x3, #VCPU_HOST_CONTEXT]
+   kern_hyp_va x0
+   add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
+   bl  __fpsimd_save_state
+
+   add x2, x3, #VCPU_CONTEXT
+   add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
+   bl  __fpsimd_restore_state
+
+   mrs x1, hcr_el2
+   tbnzx1, #HCR_RW_SHIFT, 1f
+   ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]
+   msr fpexc32_el2, x4
+1:
+   pop x4, lr
+   pop x2, x3
+   pop x0, x1
+
+   eret
+ENDPROC(__fpsimd_guest_restore)
diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S
new file mode 100644
index 000..da3f22c
--- /dev/null
+++ b/arch/arm64/kvm/hyp/fpsimd.S
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier 
+ *
+ * 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 .
+ */
+
+#include 
+
+#include 
+
+   .text
+   .pushsection.hyp.text, "ax"
+
+ENTRY(__fpsimd_save_state)
+   fpsimd_save x0, 1
+   ret
+ENDPROC(__fpsimd_save_state)
+
+ENTRY(__fpsimd_restore_state)
+   fpsimd_restore  x0, 1
+   ret
+ENDPROC(__fpsimd_restore_state)
diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
index f0427ee..18365dd 100644
--- a/arch/arm64/kvm/hyp/hyp.h
+++ b/arch/arm64/kvm/hyp/hyp.h
@@ -66,6 +66,13 @@ void __debug_restore_state(struct kvm_vcpu *vcpu,
 void __debug_cond_save_host_state(struct kvm_vcpu *vcpu);
 void __debug_cond_restore_host_state(struct kvm_vcpu *vcpu);
 
+void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);
+void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);
+static inline bool __fpsimd_enabled(void)
+{
+   return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
+}
+
 u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
 
 #endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index d67ed9e..8affc19 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -88,6 +88,7 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 {
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
+   bool fp_enabled;
u64 exit_code;
 
vcpu = kern_hyp_va(vcpu);
@@ -117,6 +118,8 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
exit_code = __guest_enter(vcpu, host_ctxt);
/* And we're baaack! */
 
+   fp_enabled = __fpsimd_enabled();
+
__sysreg_save_state(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_save_state(vcpu);
@@ -127,6 +130,11 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
 
__sysreg_restore_state(host_ctxt);
 
+   if (fp_enabled) {
+

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

Re: [PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

[PATCH v2 12/21] arm64: KVM: Implement fpsimd save/restore

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